U.S. patent application number 17/091978 was filed with the patent office on 2022-05-12 for efficient worker utilization.
This patent application is currently assigned to Oracle International Corporation. The applicant listed for this patent is Oracle International Corporation. Invention is credited to Nathaniel Martin Glass, Tanvir Singh Mundra, Christopher Richard Newcombe.
Application Number | 20220147388 17/091978 |
Document ID | / |
Family ID | |
Filed Date | 2022-05-12 |
United States Patent
Application |
20220147388 |
Kind Code |
A1 |
Mundra; Tanvir Singh ; et
al. |
May 12, 2022 |
EFFICIENT WORKER UTILIZATION
Abstract
Techniques are disclosed for efficient utilization worker
threads in a workflow-as-a-service (WFaaS) environment. A client
device may request a workflow for execution by the client device.
The client device may receive the requested workflow and initialize
a set of worker threads to execute the workflow and a set of
heartbeater threads to monitor the set of worker threads. Upon
receiving an indication of a processing delay, the client device
may capture the state of the workflow, suspend execution of the
workflow, and store the workflow in a temporary queue. While the
processing delay persists, the client device may use the set of
worker threads to execute other tasks. When the processing delay
terminates, the client device may resume execution of the
workflow.
Inventors: |
Mundra; Tanvir Singh;
(Seattle, WA) ; Newcombe; Christopher Richard;
(Kirkland, WA) ; Glass; Nathaniel Martin;
(Bellevue, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Oracle International Corporation |
Redwood Shores |
CA |
US |
|
|
Assignee: |
Oracle International
Corporation
Redwood Shores
CA
|
Appl. No.: |
17/091978 |
Filed: |
November 6, 2020 |
International
Class: |
G06F 9/48 20060101
G06F009/48; G06F 9/50 20060101 G06F009/50; G06F 21/44 20060101
G06F021/44; G06F 11/30 20060101 G06F011/30 |
Claims
1. A method comprising: transmitting, from a poller thread
executing on a client device to a server, a request for workflow
tasks; receiving, in response to the request for workflow tasks, a
set of workflow tasks, each workflow task of the set of workflow
tasks including a token, wherein the token includes a time-to-live
(TTL) value; initializing a set of worker threads, each worker
thread of the set of worker threads being configured to execute a
workflow task of the set of workflow tasks; initializing, using the
token of each workflow task, a set of heartbeater threads, each
heartbeater thread of the set of heartbeater threads being
configured to monitor an execution status of one or more worker
threads; executing, by the worker threads, the set of workflow
tasks; receiving an indication of a processing delay that prevents
the set of worker threads from completing execution of the set of
workflow tasks; suspending execution of the set of workflow tasks
by the set of worker threads; adding the set of workflow tasks to a
temporary workflow task queue; executing, by subset of worker
threads, a different task during the processing delay; determining
that the processing delay has terminated; and resuming, in response
to determining that the processing delay has terminated, execution
of the set of workflow tasks by the set of worker threads.
2. The method of claim 1, further comprising: initializing a set of
heartbeater threads, each heartbeater thread of the set of
heartbeater threads being configured to monitor an execution status
of one or more worker threads, wherein the set of heartbeater
threads is smaller than the set of worker threads.
3. The method of claim 2, further comprising: identifying a time
interval between a current time and a time when a particular
workflow task of the set of workflow tasks was received;
determining, by a particular heartbeater thread of the set of
heartbeater threads, that the time interval is greater than or
equal to the TTL value; detecting, by the particular heartbeater
thread, that the processing delay is occurring; and resetting, by
the heartbeater thread, the time interval, wherein resetting the
time interval causes the particular workflow task to be retained at
the client device.
4. The method of claim 1, further comprising: receiving, from each
worker thread of the set of worker threads, a workflow task result
and the token; authenticating the workflow task result using the
token.
5. The method of claim 1, wherein the TTL value corresponds to a
time interval over which a workflow task must be completed.
6. The method of claim 1, wherein the processing delay is caused by
a status checking process that determines a status of a downstream
device.
7. The method of claim 1, wherein the set of workflow tasks
includes a quantity of workflow tasks that is based on a snapshot
of worker thread availability.
8. A system comprising: one or more processors; a non-transitory
computer-readable medium comprising instructions that, when
executed by the one or more processors, cause the one or more
processors to perform operations including: transmitting, from a
poller thread executing on a client device to a server, a request
for workflow tasks; receiving, in response to the request for
workflow tasks, a set of workflow tasks, each workflow task of the
set of workflow tasks including a token, wherein the token includes
a time-to-live (TTL) value; initializing a set of worker threads,
each worker thread of the set of worker threads being configured to
execute a workflow task of the set of workflow tasks; initializing,
using the token of each workflow task, a set of heartbeater
threads, each heartbeater thread of the set of heartbeater threads
being configured to monitor an execution status of one or more
worker threads; executing, by the worker threads, the set of
workflow tasks; receiving an indication of a processing delay that
prevents the set of worker threads from completing execution of the
set of workflow tasks; suspending execution of the set of workflow
tasks by the set of worker threads; adding the set of workflow
tasks to a temporary workflow task queue; executing, by subset of
worker threads, a different task during the processing delay;
determining that the processing delay has terminated; and resuming,
in response to determining that the processing delay has
terminated, execution of the set of workflow tasks by the set of
worker threads.
9. The system of claim 8, wherein the operations further include:
initializing a set of heartbeater threads, each heartbeater thread
of the set of heartbeater threads being configured to monitor an
execution status of one or more worker threads, wherein the set of
heartbeater threads is smaller than the set of worker threads.
10. The system of claim 9, wherein the operations further include:
identifying a time interval between a current time and a time when
a particular workflow task of the set of workflow tasks was
received; determining, by a particular heartbeater thread of the
set of heartbeater threads, that the time interval is greater than
or equal to the TTL value; detecting, by the particular heartbeater
thread, that the processing delay is occurring; and resetting, by
the heartbeater thread, the time interval, wherein resetting the
time interval causes the particular workflow task to be retained at
the client device.
11. The system of claim 8, wherein the operations further include:
receiving, from each worker thread of the set of worker threads, a
workflow task result and the token; authenticating the workflow
task result using the token.
12. The system of claim 8, wherein the TTL value corresponds to a
time interval over which a workflow task must be completed.
13. The system of claim 8, wherein the processing delay is caused
by a status checking process that determines a status of a
downstream device.
14. The system of claim 8, wherein the set of workflow tasks
includes a quantity of workflow tasks that is based on a snapshot
of worker thread availability.
15. A non-transitory computer-readable medium comprising
instructions that, when executed by one or more processors, cause
the one or more processors to perform operations including:
transmitting, from a poller thread executing on a client device to
a server, a request for workflow tasks; receiving, in response to
the request for workflow tasks, a set of workflow tasks, each
workflow task of the set of workflow tasks including a token,
wherein the token includes a time-to-live (TTL) value; initializing
a set of worker threads, each worker thread of the set of worker
threads being configured to execute a workflow task of the set of
workflow tasks; initializing, using the token of each workflow
task, a set of heartbeater threads, each heartbeater thread of the
set of heartbeater threads being configured to monitor an execution
status of one or more worker threads; executing, by the worker
threads, the set of workflow tasks; receiving an indication of a
processing delay that prevents the set of worker threads from
completing execution of the set of workflow tasks; suspending
execution of the set of workflow tasks by the set of worker
threads; adding the set of workflow tasks to a temporary workflow
task queue; executing, by subset of worker threads, a different
task during the processing delay; determining that the processing
delay has terminated; and resuming, in response to determining that
the processing delay has terminated, execution of the set of
workflow tasks by the set of worker threads.
16. The non-transitory computer-readable medium of claim 15,
wherein the operations further include: initializing a set of
heartbeater threads, each heartbeater thread of the set of
heartbeater threads being configured to monitor an execution status
of one or more worker threads, wherein the set of heartbeater
threads is smaller than the set of worker threads.
17. The non-transitory computer-readable medium of claim 16,
wherein the operations further include: identifying a time interval
between a current time and a time when a particular workflow task
of the set of workflow tasks was received; determining, by a
particular heartbeater thread of the set of heartbeater threads,
that the time interval is greater than or equal to the TTL value;
detecting, by the particular heartbeater thread, that the
processing delay is occurring; and resetting, by the heartbeater
thread, the time interval, wherein resetting the time interval
causes the particular workflow task to be retained at the client
device.
18. The non-transitory computer-readable medium of claim 15,
wherein the operations further include: receiving, from each worker
thread of the set of worker threads, a workflow task result and the
token; authenticating the workflow task result using the token.
19. The non-transitory computer-readable medium of claim 15,
wherein the TTL value corresponds to a time interval over which a
workflow task must be completed.
20. The non-transitory computer-readable medium of claim 15,
wherein the set of workflow tasks includes a quantity of workflow
tasks that is based on a snapshot of worker thread availability.
Description
BACKGROUND
[0001] Computational intensive applications are often made up of a
set of processing tasks in which at least some may be executed
independently and in parallel. Executing computation intensive
applications on a computing device may consume an excessive amount
of processing resources impacting other processes of the computing
device, leading to longer execution times, and wasted processing
resources. Therefore, there is a need in the art for improved
methods and systems for executing computationally intensive
applications.
SUMMARY
[0002] Aspects of the present disclosure include a method for
efficient worker utilization. The method comprises: transmitting,
from a poller thread executing on a client device to a server, a
request for workflow tasks; receiving, in response to the request
for workflow tasks, a set of workflow tasks, each workflow task of
the set of workflow tasks including a token, wherein the token
includes a time-to-live (TTL) value; initializing a set of worker
threads, each worker thread of the set of worker threads being
configured to execute a workflow task of the set of workflow tasks;
initializing, using the token of each workflow task, a set of
heartbeater threads, each heartbeater thread of the set of
heartbeater threads being configured to monitor an execution status
of one or more worker threads; executing, by the worker threads,
the set of workflow tasks; receiving an indication of a processing
delay that prevents the set of worker threads from completing
execution of the set of workflow tasks; suspending execution of the
set of workflow tasks by the set of worker threads; adding the set
of workflow tasks to a temporary workflow task queue; executing, by
subset of worker threads, a different task during the processing
delay; determining that the processing delay has terminated; and
resuming, in response to determining that the processing delay has
terminated, execution of the set of workflow tasks by the set of
worker threads.
[0003] Another aspect of the present disclosure comprises a system
comprising one or more processors and a non-transitory
computer-readable media that includes instructions that when
executed by the one or more processors, cause the one or more
processors to perform the methods described above
[0004] Another aspect of the present disclosure comprises a
non-transitory computer-readable media that includes instructions
that when executed by one or more processors, cause the one or more
processors to perform the methods described above.
[0005] These illustrative embodiments are mentioned not to limit or
define the disclosure, but to provide examples to aid understanding
thereof. Additional embodiments are discussed in the Detailed
Description, and further description is provided there.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Features, embodiments, and advantages of the present
disclosure are better understood when the following Detailed
Description is read with reference to the accompanying
drawings.
[0007] FIG. 1 is a block diagram of workflow-as-a-service system
that distributes processing tasks to remote clients, according to
certain embodiments of the present disclosure.
[0008] FIG. 2 is a block diagram of client-side execution of
distributed workflows, according to certain embodiments of the
present disclosure.
[0009] FIG. 3 is a block diagram of efficient worker utilization
during client-side execution of distributed workflows, according to
certain embodiments of the present disclosure.
[0010] FIG. 4 depicts an example flowchart of a process for
efficient worker utilization during client-side execution of
distributed workflows, according to certain embodiments of the
present disclosure.
[0011] FIG. 5 is a block diagram illustrating one pattern for
implementing a cloud infrastructure as a service system, according
to at least one embodiment.
[0012] FIG. 6 is a block diagram illustrating another pattern for
implementing a cloud infrastructure as a service system, according
to at least one embodiment.
[0013] FIG. 7 is a block diagram illustrating another pattern for
implementing a cloud infrastructure as a service system, according
to at least one embodiment.
[0014] FIG. 8 is a block diagram illustrating another pattern for
implementing a cloud infrastructure as a service system, according
to at least one embodiment.
[0015] FIG. 9 is a block diagram illustrating an example computer
system, according to at least one embodiment.
DETAILED DESCRIPTION
[0016] The methods and systems described herein involve
workflow-as-a-service (WFaaS) in which workflow processing tasks
may be distributed to one or more client devices within a
distributed execution environment (e.g., such as a client/server
based network, cloud network, or the like). Client devices may
request a workflow task or a set of workflow tasks from a server
for execution by the client device or by downstream devices (e.g.,
other client devices controlled by the client device). To prevent
delays or deadlocks (e.g., processor stall, workflow task
dependencies, memory lock contention, etc.), a lease (e.g., also
referred to as a time-to-live (TTL) or lease TTL) may be assigned
to each workflow task that represents a time interval in which the
workflow task may execute. When the lease expires before the
workflow task completes, the server may not accept the execution
result. The client device can transmit a subsequent request for the
workflow task (with a new lease) or another client device, when
requesting a workflow or workflow tasks may receive the workflow
task.
[0017] In some instances, client devices may link the transmission
of requests for additional workflow tasks to the lease time
interval. This enables the client device to request additional
processing tasks each time the lease for each of a set of workflow
tasks expires (e.g., due to the workflow tasks completing or
otherwise returning to the server). Client devices may modulate the
lease time interval to increase or decrease the frequency with
which the client device transmits requests for additional workflow
tasks to the server. Increasing the request frequency (e.g.,
reducing the lease time interval) may prevent the client device
from being idle by obtaining additional workflow tasks more
frequently at the cost of the lease of some workflow tasks expiring
before those tasks complete. The client device may increase the
lease time interval (e.g., reducing the request interval) to ensure
that all requested workflow tasks have sufficient time to
successfully execute at the expense of client device downtime
(e.g., due to a time interval between completion of the workflow
tasks and the subsequent request for additional workflow
tasks).
[0018] In other instances, the client device may separate the
transmission of requests for additional workflow tasks and the
lease time interval. This enables the client device to request
additional workflow tasks while other workflow tasks are still
being processed by the client device to maintain a high processing
load. For example, the client device may execute one or more poller
threads that can request additional workflow tasks at a time just
before a set of workflow tasks are expected to be completed by a
corresponding set of worker threads (e.g., when the lease time
interval has not yet expired). The client device may receive the
new workflow tasks as the previous workflow tasks are returned to
the server and assign the new workflow tasks to the now idle worker
threads. Decoupling poller threads' requests for workflow tasks
from the lease time interval increases worker thread utilization
and reduces system downtime (e.g., idle worker threads). The client
device may also include one or more heartbeater threads that
execute to monitor the execution of one or more worker threads. If
a worker thread is executing correctly, but the lease time interval
for the workflow tasks being executed is about to expire, the
heartbeater thread may renew the token assigned to each workflow
task which includes the lease (e.g., restarting the lease time
interval). This prevents the execution progress of the worker
thread from being lost if the lease (time interval) expires.
[0019] Since the request for workflow tasks is decoupled from the
lease time interval the poller thread may request additional
workflow tasks at any frequency set by the client device and/or the
server. For instance, the client device may define a dynamic
polling frequency that is based on a snapshot of client device
resource availability. For instance, the client device may obtain a
snapshot of available processing resources that represents
currently available processing resources of the client device
(e.g., a quantity of idle worker threads and/or heartbeater
threads, processing bandwidth, memory bandwidth, etc.). The client
device may then request a set of workflow tasks that can be
completed with the currently available processing resources. In
some instances, the client device may transmit the snapshot to the
server and the server may determine based on the snapshot the set
of workflow tasks. The server may determine the set of workflow
tasks based on a larger set of workflow tasks available at the
server in the server's workflow queue. Additionally, or
alternatively, the server may define a dynamic polling frequency
based on a quantity of available workflow tasks or a frequency in
which new workflow tasks are added to the server's work queue.
[0020] The client device may execute other operations while
executing the workflow tasks. If the client device schedules a high
priority operation for execution, the client device may pause
execution of the workflow tasks. The client device may halt
execution of the workflow tasks to free up the processing resources
for executing the high priority operation. The client device may
halt execution of the threads (e.g., some or all of the worker
threads as needed to free up a minimum requested resources). In
some instances, the poller threads and heartbeater threads may not
be terminated. Since the workflow tasks are halted, the poller
thread may not get additional work from the server and the
heartbeater may have fewer (if any) worker threads to monitor. As a
result, halting the worker threads may also reduce the processing
resources consumed by the poller threads and heartbeater threads
without having to halt the poller threads and heartbeater threads.
The client device may return the workflow tasks to the server
(e.g., using a ReportResult function with a predetermined value
that is indicative to the server that execution of the workflow
tasks by the client device is halted for a predetermined time
interval). The server then marks the workflow tasks as being
capable of being resumed by the client device (e.g., using a
ResumeFutureWork function). The server returns the workflow tasks
to the work queue (e.g., using a LeaseLoader function). When the
high priority operation terminates, the poller thread of the client
device may request the workflow tasks from the server (e.g., using
a PollForWork function).
[0021] In some instances, the client device may reduce the
processing resources consumed in halting execution of the workflow
tasks (e.g., caused by returning the workflow tasks to the server
and then requesting the workflow tasks again later) by storing the
workflow tasks locally. For example, the client device may execute
a client side yield with delay, in which the workflow tasks
executed by the worker threads is returned to a temporary worker
queue. The heartbeater thread communicates with the server to
ensure the workflow tasks do not timeout (e.g., return to the
server due to excessive execution time). The worker thread is now
free to execute the high priority operation. When the high priority
operation terminates, the client device redistributes the workflow
tasks in the temporary worker queue back to the worker threads to
resume execution of the workflow. This reduces the processing
resources needed to return the workflow tasks only to have to
re-request the workflow tasks, network resources (e.g., bandwidth,
etc.) needed to transfer workflow tasks to and from the client
device, and execution time by reducing downtime (e.g.,
non-executing time) of the client device waiting for the workflow
tasks to transfer to the server or return from the server.
[0022] FIG. 1 depicts an example block diagram of
workflow-as-a-service system that distributes processing tasks to
remote clients, according to certain embodiments of the present
disclosure. A workflow-as-a-service system includes one or more
client-side devices that execute some or all (executable tasks) of
a workflow and one or more server-side systems that manage the
execution of workflows distributed client devices. The server
environment may receive a workflow specification and/or metadata.
The workflow specification may include an identification of one or
more discrete workflow steps (e.g., tasks). The metadata may
include additional information about the workflow. Examples of
values included in the metadata can include, but are not limited
to, expected overall workflow execution time, workflow
name/identifier, major version, minor version, combinations
thereof, or the like. Metadata may also include additional
information associated with a workflow task such as, but not
limited to, task name/identifier, version, expected execution time,
heartbeat frequency, combinations thereof, or the like.
[0023] Workflow tasks may be executed within execution environment
104 of a client device. Execution environment 104 may correspond to
an environment in which the client device executes any code (e.g.,
an environment that executes both local processes and workflow
tasks). Alternatively, the client device may isolate execution
environment 104 from local processes of the client device to
prevent local processes from interfering with the execution of
workflow tasks and workflow tasks from interfering with the local
tasks. The client device may provision (volatile and/or
non-volatile) memory that is isolated from local processes to
provide a secure execution environment for the workflow tasks.
[0024] In some instances, execution environment 104 may be a
virtual environment such as a virtual machine. The virtual machine
may be configured based on the workflow tasks designated for
execution by the client device. For example, a virtual machine may
be configured to simulate a particular operating environment
suitable for the execution of particular workflow tasks. For
example, the virtual machine may be configured to simulate a
particular instruction set architecture (e.g., x86, PowerPC, etc.),
operating system, or the like.
[0025] The client device may execute multiple virtual machines with
virtual machine including execution environment 104. Each virtual
machine being configured for a particular workflow or workflow task
to enable the client device to execute different workflow tasks in
parallel. Alternatively, or additionally, the client device may
provision one or more other client devices for execution of
workflows or workflow tasks under the operation of the client
device. Provisioning the one or more other client device may
include instantiating one or more virtual machines on each of the
one or more other client devices. The client device may then
distribute workflows or workflow tasks received by the client
device to each of the one or more other client devices and
coordinate the execution of workflows or workflow tasks.
[0026] A hypervisor may be utilized to configure, instantiate,
and/or manage virtual machines executing on the client device (and
optionally the one or more other client devices). The hypervisor
may be stored and executed by the client device, by each device
executing a virtual machine, by the server, by another remote
device, or the like. For example, the hypervisor may receive a
specification of a particular operating environment and a target
device. The hypervisor may then configure a virtual machine
according to the particular operating environment and instantiate
the virtual machine on the target device.
[0027] Execution environment 104 includes threads configured to
assess current processing loads and request workflows, manage
execution of workflows and workflow tasks, and execute workflows
and workflow tasks. Poller 108 includes a thread that executes to
identify a current processing load of the client device (e.g., by
determining an amount of available memory, processor load,
networking bandwidth, an amount of available workers 112, or the
like). Poller 108 may generate a snapshot of the current processing
resources of the client device and, based on the snapshot,
determine whether to request additional workflow tasks and request
workflow tasks that can be executed using the resources that are
available. Poller 108 may generate the snapshot of the current
processing resources of the client device at regular intervals,
upon receiving a notification that a worker has completed
execution, upon receiving user input, upon receiving input from a
remote device such as the server, or the like.
[0028] For example, poller 108 may generate a snapshot at regular
intervals (called the polling interval) as set by the client
device, the server (e.g., server host(s) 128), or a user. Upon
generating a particular snapshot, poller 108 may determine a
quantity of available workers 112 that are currently available
(e.g., not currently executing). If the quantity of available
workers 112 is greater than a threshold quantity, then poller 108
may initiate a request for workflow tasks from the server. In some
instances, poller 108 may request a particular set of workflow
tasks based on the quantity of available workers 112. If the
quantity of available workers 112 is not greater than a threshold
quantity, then poller 108 may wait until the next polling interval
and generate an updated snapshot. This process may continue for as
long as the client device is configured to execute workflow tasks
or until a high priority event is detected (e.g., a processing
tasks that is higher priority than the workflow tasks). For
example, if the client device has a high priority tasks scheduled
for execution, the poller may be interrupted until the client
device is ready to resume execution of workflow tasks.
[0029] Poller 108 may request workflow tasks by transmitting a poll
token to server host 128. Server host 128 can include one or more
distributed servers that distribute workflows to client devices.
The poll token may include information identifying a workflow task
or workflow task types. As an example, the poll token can include
workflow name, workflow identifier, workflow type, workflow version
(e.g., major version and/or minor version), priority, combination
thereof, or the like. For instances, the poll token may be
WorkflowName.Type, where "Type" can refer to the lease type or the
particular task within the workflow specification. The poll token
may include one or more wildcards to increase the likelihood that
server host 128 is able to return workflow tasks to poller 108. For
example, the wildcard may be used within the workflow type and/or
the workflow version (e.g., in the major version and/or the minor
version).
[0030] When the server receives the poll token, the poll token may
be hashed using a hash function (e.g., consistent hashing
function). Lease distribution unit 136 may use consistent hashing
(e.g., using a particular hash function) to hash poll tokens (at
124) to route poll tokens to particular server hosts 128. Using the
hashed value of the poll token, the poll token may be forwarded to
a particular server host 128 that has the workflow tasks preloaded
in a cache (e.g., lease loader 132).
[0031] The request with the poll token is received by workflow
lease distribution unit 136. Workflow lease distribution unit 136
decodes the poll token to retrieve the requested workflows and
passes the request to a particular lease loader 132. Lease loader
132 can search the workflow queue for available workflow tasks that
correspond to poll token. Lease loader 132 may identify available
workflows by name and/or by type depending on whether the poll
token includes wildcards. For example, the poll token may include a
workflow name and a wildcard for lease type such that lease loader
132 may return any workflow tasks that correspond to that workflow
name regardless of lease type (e.g., any lease type). If a priority
field is included, lease loader 132 may identify workflows that
have higher priority and return those workflow tasks first. If the
poll token does not include a priority field or if multiple tasks
have the same priority, lease loader 132 may use a first come first
serve algorithm in which lease loader 132 may identify the first
workflow task that meets the poll token's criteria.
[0032] Server host 128 may include a lease token with each workflow
task included in the identified workflow. The lease token can
include an indication of a time interval over which the
corresponding workflow task is to execute. During this time
interval, the workflow task is considered "alive". The time
interval prevents unexpected delays, or memory locks or deadlocks,
processor stalls, or other processing faults from affecting the
timely execution of the workflow. In the event that the time
interval expires, the server may not accept the execution result
and the workflow task may revert back to server host 128 for
redistribution. Server host 128 may then distribute the workflow
task back to execution environment 104 (if requested by poller 108)
or to another poller thread of another client device. The lease
token prevents one or more workflow tasks that fail to execute
timely, from holding up the execution of the workflow.
[0033] Lease loader 132 may return the identified workflow task to
workflow lease distribution unit 136. The identified workflow and
corresponding leases may be transmitted back to poller 108 of the
client device.
[0034] Upon receiving one or more workflow tasks from server host
128 (and verifying the integrity of the workflow using the poll
token), poller 108 may initialize a set of threads for the
execution of the set of workflow tasks that make up the workflow.
The set of threads include worker threads (e.g., workers 112) and
heartbeater threads (e.g., heartbeaters 116). Workers 112 include a
pool of threads that execute workflow tasks. The client device may
have any number of worker threads. In some instances, the quantity
of worker threads is larger (and in some instances much larger)
than the quantity of poller threads. Poller 108 may initialize a
set of worker threads for execution of the received workflow tasks.
Poller 108 may distribute some or all of the workflow tasks (e.g.,
depending on the quantity of available worker threads and/or the
quantity of workflow tasks).
[0035] Heartbeaters 116 may include a pool of heartbeater threads
that are each configured to monitor the status of worker threads.
In some instances, each heartbeater thread monitors execution of
one worker thread (e.g., one-to-one). In other instances, each
heartbeater thread monitors execution of two or more worker threads
(e.g., one-to-many) such that, when the client device is executing
workflow tasks, the client device executes fewer heartbeater
threads than worker threads. A heartbeater thread may continuously
monitor worker threads to determine if a worker thread is executing
properly (e.g., not stalled, waiting, subject to a memory deadlock,
paused, or the like) and to ensure the worker thread completes
execution within the lease time interval. Poller 108 may assign one
or more worker threads to heartbeater 116 by transmitting (to
heartbeaters 116) an identification of the one or more worker
threads and the lease token that corresponds to the workflow task
distributed to the one or more worker threads. The heartbeater uses
the lease token to ensure that execution of the workflow tasks by
the one or more worker threads does not exceed the lease time
interval.
[0036] As the lease time interval approaches expiry, the
heartbeater thread may determine if additional time is needed for
the worker thread to finish executing. For example, the heartbeater
thread may determine an execution status of the worker thread and
or workflow task and determines additional time is warranted, the
heartbeater thread may renew the token by transmitting a request to
the server with the token associated with the workflow task being
executed by the worker thread. The server may validate the token
and issue an updated and/or new token with an extended validly
(e.g., a new or extended time interval).
[0037] If execution of a worker thread exceeds the maximum allowed
time interval of the lease, the responsible heartbeater thread may
execute corrective action to prevent the workflow task from
impacting execution of the entire workflow. For example, a worker
thread may encounter a fault (e.g., unexpected delay, memory
deadlocks, processor stalls, etc.) that causes the worker thread to
execute for a time interval that is longer than the maximum lease
time interval allowed. When a lease time interval expires, the
heartbeater thread may determine whether the worker thread is still
executing. If the worker thread is executing, the heartbeater may
interrupt the worker thread and halt the execution of the worker
thread. The heartbeater thread may prevent a worker thread from
executing indefinitely and holding up other workflow tasks or
wasting processing resources of the client device
[0038] The heartbeater thread may determine to stop renewing the
lease at any time (e.g., detecting a processing fault at the worker
thread and at expiration of the lease time interval, detecting an
improbable or incorrect execution result, or the like). In other
instances, the heartbeater thread may terminate the worker thread
and discard the lease token. Upon expiration of the lease time
interval, the workflow task automatically reverts back to server
host 128 for reassignment to the client device (upon request by
poller 108) or to another client device (upon request by a poller
of that client device).
[0039] Heartbeaters 116 may request to renew lease tokens to keep
workflow tasks alive during operations that pause the execution of
workflows, such as, higher priority processing tasks, local
processing tasks, status checks (of other client devices,
downstream devices, managed devices, or the like). For example,
when the client device executes a client-side delay (e.g., to
assess the status of downstream workflow devices or when a device
requests the status of the client device), execution of the
workflow by workers 112 may be paused. The workflow tasks currently
being executed may be stored in a temporary workflow task queue
(e.g., which stores state information of the workflow tasks and/or
the worker threads executing the workflow tasks).
[0040] Heartbeaters 116 may generate a request to renew the lease
tokens of all paused workflow tasks so that the lease time interval
of the paused workflow tasks does not expire. With the workflow
paused (and queued), the client device may use the freed processing
resources to execute the client-side operations. For local
processing tasks, the client device may shift processing resources
from execution environment 104 and allocate those resources to the
local processing tasks. For client-side delays, execution
environment 104 may utilize the now available worker threads to
execute other processing tasks. When the client-side delay
terminates, the temporary workflow task queue is used to
redistribute the paused workflow tasks back to workers 112. The
temporary workflow task queue also transfers the state information
of each workflow task (and/or the state of the worker thread
executing the workflow task) such that workflow tasks can be
resumed at the point in which execution was paused to prevent loss
of processing.
[0041] Work-item executor 140 is responsible for executing workers
112. Work-item executor 140 may also manage interrupts and delay
requests received from the local execution environment of the
client device (e.g., such as processor interrupt), from server host
128, user input, from other devices, and/or the like. For example,
when the client device executes a client-side delay, work-item
executor 140 pauses execution of workers 112 and causes the
workflow tasks to be transferred to the temporary workflow task
queue. Work-item executor 140 may then execute worker threads of
workers 112 that are configured for other tasks until the
client-side delay terminates. Work-item executor 140 may also
receive external delays from server host 128 and/or other devices.
Work-item executor may follow the same process for facilitating
external delays and resuming execution upon the termination of
external delays. For external delays, work-item executor 140 may
transmit the state information to the device requesting the delay
to provide an indication of the state of the workflow
execution.
[0042] Heartbeaters 116 monitor the execution of workers 112 by
work-item executor 140 by storing the state information of workers
112 as workers 112 execute. Heartbeaters 116 may store the state of
each worker thread as it executes. Heartbeaters 116 may synchronize
(e.g., at 120) the state of each worker thread (e.g. stored by the
heartbeater) with the current state of the worker thread reported
by work-item executor 140. Heartbeaters 116 may synchronize states
continuously (e.g., in regular intervals), in real-time, each time
a state transition occurs (e.g., as reported by work-item executor
140), or upon request.
[0043] When a step execution completes, (e.g., when a worker thread
terminates successfully), work-item executor 140 may store the
result of the execution locally within memory of the client device
and report the results to server host 128. The client device may
aggregate the results of each workflow task in the workflow to
generate a workflow final result. The workflow result may be
transmitted to server host 128.
[0044] FIG. 2 is a block diagram of client-side execution of
distributed workflows, according to certain embodiments of the
present disclosure. Client device 204 may operate one or more
execution environments (e.g., such as execution environment 104 of
FIG. 1) configured to execute workflows. The one or more execution
environments may be environments that are isolated from the local
environment of the client device (e.g., the environment that
establishes the one or more execution environment and executes
non-workflow operations). The client device may instantiate each
execution environment to operate independently from the other
execution environments and the local execution environment of the
client device. For instance, the client device may allocate a
predetermined set of processing resources to each execution
environment to enable each processing environment to execute
workflow tasks. Since the processing resources are allocated when
each execution environment is instantiated, the processing load of
other execution environments (including the local environment of
the client device) may not affect the ability of an execution
environment to execute an assigned workflow.
[0045] Client device may perform resource allocation (e.g., of
processing, memory, and/or network resources) when an execution
environment is instantiated. Resource allocation may be based on a
current processing load of the client device, an expected
processing load of the client device, a number of execution
environments instantiated, type of workflow to be executed, and/or
the like). Resource allocation may be determined by the client
device, execution environment being instantiated, a server (e.g.
such as server host 128), user input, or the like. In some
instances, modification to resources allocated to an execution
environment may be restricted to during instantiation and before
and/or after execution of a workflow. Resource allocation may be
restricted while an execution environment is executing a workflow
to prevent impacting the execution of the workflow. In other
instances, the execution environment may request additional
resources while executing a workflow. In those instances, the
resources allocated to the execution environment may be increased
but may not be decreased while the execution environment is
executing a workflow. In still yet other instances, modifications
to the allocated resources may occur at any time (e.g., during
instantiation or runtime).
[0046] Execution environment 104 instantiates poller 208, a thread
that is configured to manage acquisition of workflows for execution
environment 104, with a polling frequency value. The polling
frequency value indicates a frequency in which poller 208 is to
request workflows from server 212. The polling frequency value may
indicate that poller 208 is to execute a request for new workflow
tasks in regular intervals (e.g., every `x` milliseconds), upon
detecting the occurrence of a condition or event (e.g., when
resources of execution environment are below a predetermined
threshold, predetermined quantity of worker threads are available
for execution, receiving user input, receiving input from another
client device or server 212, or the like) or the like.
[0047] Poller 208 requests a new workflow task for execution from
server 212 by transmitting a poll token that includes an
identification of a workflow. The identification of the requested
workflow may include multiple period-delineated operands such as,
but not limited to, an identifier, a major version, a minor
version, a type, a time interval, a quantity of available worker
threads (e.g., based on current processor load, memory capacity,
network bandwidth, etc.), combinations thereof, and the like. For
example, the identification of the workflow may be: "Workflow.3.1",
which corresponds to a workflow with an identifier of "Workflow", a
major version `3`, and a minor version `1`. Server 212 may
determine if there is a matching workflow in the available workflow
queue. In some instances, server 212 may return a workflow that is
an exact match. If server 212 cannot identify a workflow that
matches, server 212 may return an indication that the requested
workflow is unavailable or could not be found and that the client
should poll later, or the like. In other instances, server 212 may
identify the closest workflow that matches the request. For
example, server 212 may identify any workflow with a same
identifier and major version but having any minor version. In those
instances, server 212 may not identify workflows with different
identifiers or different major versions as these workflows may not
be executable by execution environment 104.
[0048] In other instances, poller 208 may use wildcard operators to
specify the requested workflow. The wildcard operator may be
included within one or many of the operands (e.g., the major
version, minor version, type, and/or the like) to indicate that the
operand itself or the portion of the operand at the location of the
wildcard operator can correspond to any workflow. For instance,
poller 108 may provide "Workflow.3.*" where `*` is a wildcard
operator indicating that server 208 may identify any workflow
having the identifier "Workflow" with a major version of `3` and
having any minor version (as indicated by the wildcard operator. As
another example, poller 108 may provide "Workflow.3.1.*". In that
example, server 208 may identify any workflow having an identifier
"Workflow" and having specified major version (i.e. `3`) and minor
version (i.e. `1`) and any type (Step). The wildcard operator
enables the server to identify a larger quantity of potential
workflow tasks that can satisfy the request. As a result, it may be
more likely that the server does identifies a suitable workflow
task that will satisfy the request (and less likely that server 212
fails to return a workflow task). Since the wildcard operator
increases the number of workflow tasks that may satisfy the
request, it reduces the time that execution environment 104 is idle
or is underutilized (e.g., due to the client device waiting for a
workflow to execute) and at the same time increases system
utilization and efficiency.
[0049] Workflows distributed by server 212 include a set of
workflow tasks. Each workflow task may be a discrete portion of the
workflow that is executable by one or more threads of an execution
environment. When server 212 receives a poll token, server 208
identifies the requested workflow and initializes a set of tokens
for the workflow tasks of the workflow. A token is initialized for
each workflow task in the set of workflow tasks. In some instances,
server 212 may also generate a time-to-live (TTL) value (also known
as a lease validity value), which represents a time interval within
which a heartbeater thread is to renew the lease. The TTL value may
be determined by the workflow specification.
[0050] Server 208 then transmits the set of workflow tasks, the set
of tokens, the TTL value to execution environment 104 of client
device 204. Server 208 may later deserialize the token to
authenticate token renewals or reported results. Poller 208
receives the set of workflow tasks and initializes a set of worker
threads (worker 212-1-212-n) to execute the set of workflow tasks
and a set of heartbeater threads (heartbeater 220-1-220-i) to
monitor execution of the worker threads. Execution environment 104
may include `n` worker threads (where n is an integer that is
greater than 2). Execution environment 104 may include `i`
heartbeater threads (where `i` is an integer that is greater than
or equal to 1 and less than `n`). In other words, execution
environment includes a set of `n` worker threads that is larger
than a set of `i` heartbeater threads. Generally, each heartbeater
thread monitors the execution of two or more worker threads.
Execution environment 104 may execute less heartbeater threads than
the quantity of worker threads that are allocated to execute the
set of workflow tasks.
[0051] For example, the set of workflow tasks includes `n` workflow
tasks. Poller 208 may instantiate `n` worker threads (worker
216-1-216-n) such that each worker thread is configured to execute
a workflow task. Execution environment 104 also instantiates T
heartbeater threads where `i` is less than `n`. As shown, a first
heartbeater thread (220-1) monitors execution of two worker threads
(e.g., 216-1 and 216-2 as shown). The last heartbeater thread
(220-i) monitors the remaining worker threads that are not being
monitored by a heartbeater thread. This heartbeater thread (220-i)
may monitor worker 216-n. Heartbeater threads may automatically
load balance between heartbeater threads to ensure that tokens
remain valid. For instance, the heartbeater thread may
automatically load balance such that each heartbeater thread
monitors approximately a same quantity of worker threads as other
heartbeater threads.
[0052] The heartbeater threads ensure the worker threads execute in
a timely (e.g., terminate successfully within the TTL value). If
the time interval expires before the worker thread terminates
successfully, the results of the execution may not be accepted by
server 208. Instead, server 208 may redistribute that workflow task
upon receive a subsequent request for a workflow. The workflow task
may be requested by client device 204 or by another client device.
In some instances, the worker thread is terminated as soon as the
time interval expires to prevent wasting processing resources of
client device 204.
[0053] Execution environment 104 transmits the results of each
workflow task to server 208 along with the token. Server 208 may
verify that the workflow task results are authentic (e.g., were
received from a device authorized to execute the workflow). Server
208 may authenticate the workflow task result by deserializing the
token the token received from client device 204. If the token is
valid, then it can be determined that the workflow task result was
generated by the client device that was assigned to execute the
workflow task (i.e. an authorized device). If the token is invalid,
server 208 may discard the workflow task result and reissue the
workflow task to client device 208, another client device, or to
the first device that requests a workflow). Once each of the
workflow task results are received, server 208 may aggregate the
individual workflow task results to generate a workflow result. The
workflow result is available to be transmitted to the device or
user that defined the workflow for inspection at a later time.
[0054] FIG. 3 is a block diagram of efficient worker utilization
during client-side execution of distributed workflows, according to
certain embodiments of the present disclosure. A client device
and/or execution environment that executes workflow tasks may also
execute other processes (e.g., local processes, management
processes associated with downstream or upstream devices, high
priority tasks including other workflow tasks, combinations
thereof, and the like). In some instances, execution of other
processes may interfere with the execution of the set of workflow
tasks. For instance, a local process may require resources
currently allocated to execute workflow tasks. In other instances,
the execution environment of a client device may execute a delay
(of the execution of the workflow) for a non-processing operation
such as a status check of a downstream device (e.g., a device that
is operated or managed by the client device) or an upstream device
(e.g., a device that operates, manages, or distributes workflows to
the client device).
[0055] When a local process, high priority process (e.g., higher
priority than a priority assigned to the executing workflow), or
delay occurs, the execution environment may temporarily suspend
execution of the workflow. The execution environment may suspend
execution of the workflow and divert processing resources allocated
to the execution environment to the local or high priority process.
During a delay operation, the execution environment may suspend
execution of the workflow to prevent loss or waste of processing
resources in the event of a negative status (e.g., device
unreachable, network failure, assigned workflow has been canceled,
system or software fault, etc.) being returned. Since the delay
does not necessitate that the processing resources allocated to the
execution environment be diverted elsewhere, the execution
environment may retain the allocated processing resources.
[0056] For example, work-item executor 140 (e.g., as described in
connection with FIG. 1) may execute a workflow using `n` worker
threads (212-1, 212-2,-212-n), each worker thread executing a
workflow task of the workflow. When work-item executor 140 detects
system interrupt 304, work-item executor 140 suspend execution of
the workflow and stores an identification of each suspended
workflow task in temporary workflow task queue 308. Temporary
workflow task queue 308 also stores the state of each suspended
workflow task. The state of a workflow task indicates the point of
execution of the workflow tasks including the current value of any
variables. In some instances, the point of execution may refer to
the last line of code of the workflow task that executed or the
next line of code that is to execute.
[0057] At each heartbeat time interval (e.g., lease TTL value),
heartbeaters 116 may synchronize (at 120) the state of each worker
thread monitored by heartbeaters 116 (at the time in which the
workflow task is suspended) with the state output from work-item
executor 140. Although the workflow tasks are paused, the lease TTL
value of each corresponding token does not reset. As a result, a
suspended workflow task may not finish executing within the time
interval set by the lease TTL value (e.g., as the least TTL value
expires). This may cause the execution of the workflow task to fail
(e.g., server host 128 may not accept the execution result when
execution of the workflow task resumes). If the workflow task
fails, poller 108 may request the workflow task from server host
128 and the workflow task may start executing from the
beginning.
[0058] Heartbeaters 116 may prevent the lease TTL value from
expiring by renewing each token with server host 128. Heartbeater
116 may request a new token for each suspended workflow task. The
renewed token includes a new lease TTL value (e.g., new time
interval over which the workflow task is to execute). The new time
interval may of a same length as the lease TTL value or may be
equal to a specified task execution time (e.g., specified by an
assignment TTL value).
[0059] Since the workflow tasks are suspended, the worker threads
assigned to execute the workflow tasks may remain idle. The
execution environment may execute other processes using the worker
threads during the delay to prevent the worker threads (and the
client device) from remaining idle. The execution environment may
include processing queue 312. Upon receiving a delay operation that
suspends execution of a workflow, work-item executor 140 may
execute a process from processing queue 312 using the idle worker
threads. Examples of processes include, but are not limited to,
other workflow tasks (e.g., workflow tasks scheduled to execute
after the current workflow, workflow tasks assigned to another
execution environment or client device, or the like), local
processes of the client device, diagnostic processes (e.g.
processing, memory, and/or networking diagnostics, error/fault
correction processes, processes assigned by server host 128, or the
like).
[0060] When the delay terminates, work-item executor may retrieve
the suspended workflow tasks from temporary workflow task queue 308
and the corresponding state information. Work-item executor 140 may
then resume execution of each workflow task using the worker
threads (e.g., workers 212-1-212-n) at the point of execution when
execution was suspended. Work-item executor 140 may output updated
state information to heartbeaters 116 (through box 120) to enable
heartbeaters 116 may to continue to monitor the execution of the
worker threads.
[0061] FIG. 4 depicts an example flowchart of a process for
efficient worker utilization during client-side execution of
distributed workflows, according to certain embodiments of the
present disclosure. At block 404, a client device requests a
workflow task from a server for execution by the client device. The
request may include an identification of the workflow that is
requested. For instance, the request may include one or more period
delineated operands (e.g., alphanumeric characters) such as, but
not limited to, an identifier, type, major version, minor version,
type, or the like. The server may identify the workflow that
includes each operand. For instance, if the request includes
Workflow.1.3, the server will return a workflow with an identifier
of "Workflow", a major version of 1, and a minor version of 3.
[0062] In some instances, one or more operands can include a
wildcard that enables the server to identify any workflow that
includes the other operands. For instance, for Workflow.1.* (where
`*` represents the wildcard), the server may return a workflow with
an identifier of "Workflow", a major version of 1, and any minor
version and or any step type. The wildcard may be included in place
of an operand or in a position within the operand. When positioned
with an operand the server may identify a workflow that matches the
portion of the operand up to the wildcard and having any portion of
the operand after the wildcard. For instance, for Workflow.*.*.*.,
the server may return "Workflow. 3.1." because the identifier
matches the wildcards. The server may also return tasks for
"Workflow.3.2". The wildcard enables the server to identify more
workflows that may satisfy the constraints of the request, which
may increase the likelihood that server is able to satisfy the
request with a workflow.
[0063] At block 408, the client device may receive a set of
workflow tasks from the server. The set of tasks correspond to the
requested workflow. Each workflow task may include a token that
indicates a time-to-live (TTL) value. The TTL value represents a
time interval over which the workflow task is to execute. If the
workflow task fails to execute before the time interval of the TTL
value expires, the workflow task may be terminated. In some
instances, when the time interval of the TTL value expires, the
execution result of the workflow task may not be accepted. Instead
the server the client device may request the workflow task from the
server and execute the workflow task again.
[0064] At block 412, the client device may initialize a set of
worker threads. In some instances, each worker thread may be
configured to execute a workflow task of the set of workflow tasks
(e.g., one-to-one). In other instances, two or more threads may be
configured to execute a workflow task. In still yet other
instances, one workflow task may be configured to execute on two or
more workflow tasks.
[0065] At block 416, the client device may initialize a set of
heartbeater threads using the token. Each heartbeater thread may be
configured to monitor an execution status of one or more worker
threads. In some instances, the set of heartbeater threads may be
less than the set of worker threads. In those instances, at least
one heartbeater thread monitors the execution of two or more worker
threads. The heartbeater thread can use the token to ensure that
execution of the workflow task by a worker thread does not exceed
the time interval of the TTL value. For example, if a workflow task
fails to execute within the time interval of the TTL value, the
workflow task may have to be re-executed by the client device. To
avoid wasteful processing of duplicate workflow tasks, the client
device may utilize heartbeater threads to monitor worker threads
and take remedial action if worker threads fail to execute
correctly.
[0066] For example, if a worker thread fails to execute a workflow
task within the time interval of the TTL value, the heartbeater may
first determine if the worker thread is executing. If the worker
thread is executing, then heartbeater may request to renew the
token (e.g., reset the time interval of the TTL value). This gives
the worker thread more time to execute the workflow task and
prevents the client device from having to request the workflow
task, receive the workflow task, and re-execute the workflow task
from the beginning. If the worker thread has been executing beyond
the time interval of the TTL value, the heartbeater thread may
terminate the worker thread. The workflow task may be immediately
reassigned to another worker thread so that the workflow task may
execute within the time interval of the TTL.
[0067] At block 420, the client device executes the set of workflow
tasks using the set of worker threads.
[0068] At block 424, an indication of a processing delay is
received. The indication may be, for example, a notification, a
software or processor interrupt, a communication from a remote
device, or the like. For example, the processing delay may be
triggered when the client device must execute another process such
as a higher priority process, a process that requires the resources
allocated to the execution of the set of workflow tasks, status
check (e.g., to a downstream or upstream device), or the like. The
processing delay may prevent the execution of the set of workflow
tasks from completing.
[0069] At block 428, the client device, in response to receiving
the indication of the processing delay, suspends execution of the
set of workflow tasks by the set of worker threads. The client
devices may determine the state of each workflow task so that
execution of the workflow tasks can be resumed at the point of the
workflow task in which execution was suspended. For example, the
state may represent the last (or next) line of code to execute
and/or the value of variables, data structures, memory registers,
or the like. Capturing the state of each workflow task prevents the
client device from having to re-execute some or all of a workflow
task when execution of the set of workflow tasks resumes.
[0070] At block 432, the client device transfers the set of
workflow tasks to a temporary workflow task queue. The temporary
workflow task queue may store the set of workflow tasks and the
corresponding state of each workflow task. In some instances, the
temporary workflow task queue may be allocated in non-volatile
memory to store workflow tasks for an indefinite time interval
(e.g., while a processing delay is ongoing). In other instances,
the client device may allocate memory for temporary workflow task
queue upon receiving the indication of the processing delay while
workflow tasks are execution. In those instances, the client device
may allocate non-volatile or volatile memory for the temporary
workflow task queue and deallocate the memory as soon as the
execution of the set of workflow tasks resumes.
[0071] Since the workflow tasks are suspended and stored in the
temporary workflow task queue, it is possible that the workflow
tasks will complete execution within the time interval specified by
the TTL value. The heartbeater threads may prevent the time
interval of the TTL value from expiring by obtaining new tokens for
each workflow thread. For example, the heartbeater threads may
request to renew each token of each workflow task from the server
as the time interval of the TTL value approaches expiration.
Renewing the tokens may include resetting the time interval of the
TTL value to get an extended validity of the token.
[0072] At block 436, the client device executes a set of different
tasks using the set of worker threads. Since the processing delay
caused execution of the workflow tasks to be suspended, the worker
threads may remain idle until execution of the workflow tasks
resumes. To avoid system idle time in which the client device, the
client device may execute other tasks while waiting for the
processing delay to terminate. The client device may include a task
queue that includes processes that may be waiting for execution. In
some instances, the tasks in the task queue may be low priority
tasks (e.g., tasks that may not be scheduled to execute unless the
client device is idle) such as diagnostic processes (e.g.,
processing diagnostics, network diagnostics, etc.), or the like. In
other instances, the task queue may be filled with tasks associated
with other non-workflow related applications, tasks associated with
other workflows, tasks assigned from another device (e.g., such as
server, other client devices, or the like).
[0073] At block 440, the client device determines that the
processing delay has terminated. For instance, the client device
may receive an indication that the process delay has terminated
(e.g., a notification, processor of software interrupt, a
communication, or the like). Alternatively, the client device may
determine that the processing delay has terminated based on the
indication of the processing delay received at block 424. For
instance, when the client device receives the indication of the
processing delay, the client device may also receive an indication
of when the processing delay will terminate. The indication may
specify a termination time, a termination time interval, and/or a
termination event (e.g., a high priority task terminated, available
processing resources is greater than a threshold, the status of a
downstream or upstream device is received, or the like). For
instance, the client device may determine that the processing delay
has terminated when the current time is equal to the termination
time.
[0074] At block 444, the client device resumes execution of the set
of workflow tasks by the set of worker threads. For example, the
client device may initialize execution of the set of workflow tasks
stored in the temporary workflow task queue. The client device may
then use the state information of each workflow task to resume
execution the workflow task at the point of execution when the
workflow task was suspended. For example, the state information may
indicate the last line of code of the workflow task that executed.
The worker thread may then resume executing the workflow task at
the next line of code of the workflow task.
[0075] The client device stores the result of the execution of each
workflow task when the worker threads complete. The client device
may aggregate the results of each workflow task to generate a
workflow result (e.g., the result of the workflow requested by the
client device. Alternatively, the client device may transmit the
result of the execution of each workflow task as the workflow tasks
finish executing.
[0076] As noted above, infrastructure as a service (IaaS) is one
particular type of cloud computing. IaaS can be configured to
provide virtualized computing resources over a public network
(e.g., the Internet). In an IaaS model, a cloud computing provider
can host the infrastructure components (e.g., servers, storage
devices, network nodes (e.g., hardware), deployment software,
platform virtualization (e.g., a hypervisor layer), or the like).
In some cases, an IaaS provider may also supply a variety of
services to accompany those infrastructure components (e.g.,
billing, monitoring, logging, security, load balancing and
clustering, etc.). Thus, as these services may be policy-driven,
IaaS users may be able to implement policies to drive load
balancing to maintain application availability and performance.
[0077] In some instances, IaaS customers may access resources and
services through a wide area network (WAN), such as the Internet,
and can use the cloud provider's services to install the remaining
elements of an application stack. For example, the user can log in
to the IaaS platform to create virtual machines (VMs), install
operating systems (OSs) on each VM, deploy middleware such as
databases, create storage buckets for workloads and backups, and
even install enterprise software into that VM. Customers can then
use the provider's services to perform various functions, including
balancing network traffic, troubleshooting application issues,
monitoring performance, managing disaster recovery, etc.
[0078] In most cases, a cloud computing model will require the
participation of a cloud provider. The cloud provider may, but need
not be, a third-party service that specializes in providing (e.g.,
offering, renting, selling) IaaS. An entity might also opt to
deploy a private cloud, becoming its own provider of infrastructure
services.
[0079] In some examples, IaaS deployment is the process of putting
a new application, or a new version of an application, onto a
prepared application server or the like. It may also include the
process of preparing the server (e.g., installing libraries,
daemons, etc.). This is often managed by the cloud provider, below
the hypervisor layer (e.g., the servers, storage, network hardware,
and virtualization). Thus, the customer may be responsible for
handling (OS), middleware, and/or application deployment (e.g., on
self-service virtual machines (e.g., that can be spun up on demand)
or the like.
[0080] In some examples, IaaS provisioning may refer to acquiring
computers or virtual hosts for use, and even installing needed
libraries or services on them. In most cases, deployment does not
include provisioning, and the provisioning may need to be performed
first.
[0081] In some cases, there are two different problems for IaaS
provisioning. First, there is the initial challenge of provisioning
the initial set of infrastructure before anything is running.
Second, there is the challenge of evolving the existing
infrastructure (e.g., adding new services, changing services,
removing services, etc.) once everything has been provisioned. In
some cases, these two challenges may be addressed by enabling the
configuration of the infrastructure to be defined declaratively. In
other words, the infrastructure (e.g., what components are needed
and how they interact) can be defined by one or more configuration
files. Thus, the overall topology of the infrastructure (e.g., what
resources depend on which, and how they each work together) can be
described declaratively. In some instances, once the topology is
defined, a workflow can be generated that creates and/or manages
the different components described in the configuration files.
[0082] In some examples, an infrastructure may have many
interconnected elements. For example, there may be one or more
virtual private clouds (VPCs) (e.g., a potentially on-demand pool
of configurable and/or shared computing resources), also known as a
core network. In some examples, there may also be one or more
security group rules provisioned to define how the security of the
network will be set up and one or more virtual machines (VMs).
Other infrastructure elements may also be provisioned, such as a
load balancer, a database, or the like. As more and more
infrastructure elements are desired and/or added, the
infrastructure may incrementally evolve.
[0083] In some instances, continuous deployment techniques may be
employed to enable deployment of infrastructure code across various
virtual computing environments. Additionally, the described
techniques can enable infrastructure management within these
environments. In some examples, service teams can write code that
is desired to be deployed to one or more, but often many, different
production environments (e.g., across various different geographic
locations, sometimes spanning the entire world). However, in some
examples, the infrastructure on which the code will be deployed
must first be set up. In some instances, the provisioning can be
done manually, a provisioning tool may be utilized to provision the
resources, and/or deployment tools may be utilized to deploy the
code once the infrastructure is provisioned.
[0084] FIG. 5 is a block diagram 500 illustrating an example
pattern of an IaaS architecture, according to at least one
embodiment. Service operators 502 can be communicatively coupled to
a secure host tenancy 504 that can include a virtual cloud network
(VCN) 506 and a secure host subnet 508. In some examples, the
service operators 502 may be using one or more client computing
devices, which may be portable handheld devices (e.g., an
iPhone.RTM., cellular telephone, an iPad.RTM., computing tablet, a
personal digital assistant (PDA)) or wearable devices (e.g., a
Google Glass.RTM. head mounted display), running software such as
Microsoft Windows Mobile.RTM., and/or a variety of mobile operating
systems such as iOS, Windows Phone, Android, BlackBerry 8, Palm OS,
and the like, and being Internet, e-mail, short message service
(SMS), Blackberry.RTM., or other communication protocol enabled.
Alternatively, the client computing devices can be general purpose
personal computers including, by way of example, personal computers
and/or laptop computers running various versions of Microsoft
Windows.RTM., Apple Macintosh.RTM., and/or Linux operating systems.
The client computing devices can be workstation computers running
any of a variety of commercially-available UNIX.RTM. or UNIX-like
operating systems, including without limitation the variety of
GNU/Linux operating systems, such as for example, Google Chrome OS.
Alternatively, or in addition, client computing devices may be any
other electronic device, such as a thin-client computer, an
Internet-enabled gaming system (e.g., a Microsoft Xbox gaming
console with or without a Kinect.RTM. gesture input device), and/or
a personal messaging device, capable of communicating over a
network that can access the VCN 506 and/or the Internet.
[0085] The VCN 506 can include a local peering gateway (LPG) 510
that can be communicatively coupled to a secure shell (SSH) VCN 512
via an LPG 510 contained in the SSH VCN 512. The SSH VCN 512 can
include an SSH subnet 514, and the SSH VCN 512 can be
communicatively coupled to a control plane VCN 516 via the LPG 510
contained in the control plane VCN 516. Also, the SSH VCN 512 can
be communicatively coupled to a data plane VCN 518 via an LPG 510.
The control plane VCN 516 and the data plane VCN 518 can be
contained in a service tenancy 519 that can be owned and/or
operated by the IaaS provider.
[0086] The control plane VCN 516 can include a control plane
demilitarized zone (DMZ) tier 520 that acts as a perimeter network
(e.g., portions of a corporate network between the corporate
intranet and external networks). The DMZ-based servers may have
restricted responsibilities and help keep security breaches
contained. Additionally, the DMZ tier 520 can include one or more
load balancer (LB) subnet(s) 522, a control plane app tier 524 that
can include app subnet(s) 526, a control plane data tier 528 that
can include database (DB) subnet(s) 530 (e.g., frontend DB
subnet(s) and/or backend DB subnet(s)). The LB subnet(s) 522
contained in the control plane DMZ tier 520 can be communicatively
coupled to the app subnet(s) 526 contained in the control plane app
tier 524 and an Internet gateway 534 that can be contained in the
control plane VCN 516, and the app subnet(s) 526 can be
communicatively coupled to the DB subnet(s) 530 contained in the
control plane data tier 528 and a service gateway 536 and a network
address translation (NAT) gateway 538. The control plane VCN 516
can include the service gateway 536 and the NAT gateway 538.
[0087] The control plane VCN 516 can include a data plane mirror
app tier 540 that can include app subnet(s) 526. The app subnet(s)
526 contained in the data plane mirror app tier 540 can include a
virtual network interface controller (VNIC) 542 that can execute a
compute instance 544. The compute instance 544 can communicatively
couple the app subnet(s) 526 of the data plane mirror app tier 540
to app subnet(s) 526 that can be contained in a data plane app tier
546.
[0088] The data plane VCN 518 can include the data plane app tier
546, a data plane DMZ tier 548, and a data plane data tier 550. The
data plane DMZ tier 548 can include LB subnet(s) 522 that can be
communicatively coupled to the app subnet(s) 526 of the data plane
app tier 546 and the Internet gateway 534 of the data plane VCN
518. The app subnet(s) 526 can be communicatively coupled to the
service gateway 536 of the data plane VCN 518 and the NAT gateway
538 of the data plane VCN 518. The data plane data tier 550 can
also include the DB subnet(s) 530 that can be communicatively
coupled to the app subnet(s) 526 of the data plane app tier
546.
[0089] The Internet gateway 534 of the control plane VCN 516 and of
the data plane VCN 518 can be communicatively coupled to a metadata
management service 552 that can be communicatively coupled to
public Internet 554. Public Internet 554 can be communicatively
coupled to the NAT gateway 538 of the control plane VCN 516 and of
the data plane VCN 518. The service gateway 536 of the control
plane VCN 516 and of the data plane VCN 518 can be communicatively
couple to cloud services 556.
[0090] In some examples, the service gateway 536 of the control
plane VCN 516 or of the data plane VCN 518 can make application
programming interface (API) calls to cloud services 556 without
going through public Internet 554. The API calls to cloud services
556 from the service gateway 536 can be one-way: the service
gateway 536 can make API calls to cloud services 556, and cloud
services 556 can send requested data to the service gateway 536.
But, cloud services 556 may not initiate API calls to the service
gateway 536.
[0091] In some examples, the secure host tenancy 504 can be
directly connected to the service tenancy 519, which may be
otherwise isolated. The secure host subnet 508 can communicate with
the SSH subnet 514 through an LPG 510 that may enable two-way
communication over an otherwise isolated system. Connecting the
secure host subnet 508 to the SSH subnet 514 may give the secure
host subnet 508 access to other entities within the service tenancy
519.
[0092] The control plane VCN 516 may allow users of the service
tenancy 519 to set up or otherwise provision desired resources.
Desired resources provisioned in the control plane VCN 516 may be
deployed or otherwise used in the data plane VCN 518. In some
examples, the control plane VCN 516 can be isolated from the data
plane VCN 518, and the data plane mirror app tier 540 of the
control plane VCN 516 can communicate with the data plane app tier
546 of the data plane VCN 518 via VNICs 542 that can be contained
in the data plane mirror app tier 540 and the data plane app tier
546.
[0093] In some examples, users of the system, or customers, can
make requests, for example create, read, update, or delete (CRUD)
operations, through public Internet 554 that can communicate the
requests to the metadata management service 552. The metadata
management service 552 can communicate the request to the control
plane VCN 516 through the Internet gateway 534. The request can be
received by the LB subnet(s) 522 contained in the control plane DMZ
tier 520. The LB subnet(s) 522 may determine that the request is
valid, and in response to this determination, the LB subnet(s) 522
can transmit the request to app subnet(s) 526 contained in the
control plane app tier 524. If the request is validated and
requires a call to public Internet 554, the call to public Internet
554 may be transmitted to the NAT gateway 538 that can make the
call to public Internet 554. Memory that may be desired to be
stored by the request can be stored in the DB subnet(s) 530.
[0094] In some examples, the data plane mirror app tier 540 can
facilitate direct communication between the control plane VCN 516
and the data plane VCN 518. For example, changes, updates, or other
suitable modifications to configuration may be desired to be
applied to the resources contained in the data plane VCN 518. Via a
VNIC 542, the control plane VCN 516 can directly communicate with,
and can thereby execute the changes, updates, or other suitable
modifications to configuration to, resources contained in the data
plane VCN 518.
[0095] In some embodiments, the control plane VCN 516 and the data
plane VCN 518 can be contained in the service tenancy 519. In this
case, the user, or the customer, of the system may not own or
operate either the control plane VCN 516 or the data plane VCN 518.
Instead, the IaaS provider may own or operate the control plane VCN
516 and the data plane VCN 518, both of which may be contained in
the service tenancy 519. This embodiment can enable isolation of
networks that may prevent users or customers from interacting with
other users', or other customers', resources. Also, this embodiment
may allow users or customers of the system to store databases
privately without needing to rely on public Internet 554, which may
not have a desired level of security, for storage.
[0096] In other embodiments, the LB subnet(s) 522 contained in the
control plane VCN 516 can be configured to receive a signal from
the service gateway 536. In this embodiment, the control plane VCN
516 and the data plane VCN 518 may be configured to be called by a
customer of the IaaS provider without calling public Internet 554.
Customers of the IaaS provider may desire this embodiment since
database(s) that the customers use may be controlled by the IaaS
provider and may be stored on the service tenancy 519, which may be
isolated from public Internet 554.
[0097] FIG. 6 is a block diagram 600 illustrating another example
pattern of an IaaS architecture, according to at least one
embodiment. Service operators 602 (e.g. service operators 502 of
FIG. 5) can be communicatively coupled to a secure host tenancy 604
(e.g. the secure host tenancy 504 of FIG. 5) that can include a
virtual cloud network (VCN) 606 (e.g. the VCN 506 of FIG. 5) and a
secure host subnet 608 (e.g. the secure host subnet 508 of FIG. 5).
The VCN 606 can include a local peering gateway (LPG) 610 (e.g. the
LPG 510 of FIG. 5) that can be communicatively coupled to a secure
shell (SSH) VCN 612 (e.g. the SSH VCN 512 of FIG. 5) via an LPG 510
contained in the SSH VCN 612. The SSH VCN 612 can include an SSH
subnet 614 (e.g. the SSH subnet 514 of FIG. 5), and the SSH VCN 612
can be communicatively coupled to a control plane VCN 616 (e.g. the
control plane VCN 516 of FIG. 5) via an LPG 610 contained in the
control plane VCN 616. The control plane VCN 616 can be contained
in a service tenancy 619 (e.g. the service tenancy 519 of FIG. 5),
and the data plane VCN 618 (e.g. the data plane VCN 518 of FIG. 5)
can be contained in a customer tenancy 621 that may be owned or
operated by users, or customers, of the system.
[0098] The control plane VCN 616 can include a control plane DMZ
tier 620 (e.g. the control plane DMZ tier 520 of FIG. 5) that can
include LB subnet(s) 622 (e.g. LB subnet(s) 522 of FIG. 5), a
control plane app tier 624 (e.g. the control plane app tier 524 of
FIG. 5) that can include app subnet(s) 626 (e.g. app subnet(s) 526
of FIG. 5), a control plane data tier 628 (e.g. the control plane
data tier 528 of FIG. 5) that can include database (DB) subnet(s)
630 (e.g. similar to DB subnet(s) 530 of FIG. 5). The LB subnet(s)
622 contained in the control plane DMZ tier 620 can be
communicatively coupled to the app subnet(s) 626 contained in the
control plane app tier 624 and an Internet gateway 634 (e.g. the
Internet gateway 534 of FIG. 5) that can be contained in the
control plane VCN 616, and the app subnet(s) 626 can be
communicatively coupled to the DB subnet(s) 630 contained in the
control plane data tier 628 and a service gateway 636 (e.g. the
service gateway of FIG. 5) and a network address translation (NAT)
gateway 638 (e.g. the NAT gateway 538 of FIG. 5). The control plane
VCN 616 can include the service gateway 636 and the NAT gateway
638.
[0099] The control plane VCN 616 can include a data plane mirror
app tier 640 (e.g. the data plane mirror app tier 540 of FIG. 5)
that can include app subnet(s) 626. The app subnet(s) 626 contained
in the data plane mirror app tier 640 can include a virtual network
interface controller (VNIC) 642 (e.g. the VNIC of 542) that can
execute a compute instance 644 (e.g. similar to the compute
instance 544 of FIG. 5). The compute instance 644 can facilitate
communication between the app subnet(s) 626 of the data plane
mirror app tier 640 and the app subnet(s) 626 that can be contained
in a data plane app tier 646 (e.g. the data plane app tier 546 of
FIG. 5) via the VNIC 642 contained in the data plane mirror app
tier 640 and the VNIC 642 contained in the data plane app tier
646.
[0100] The Internet gateway 634 contained in the control plane VCN
616 can be communicatively coupled to a metadata management service
652 (e.g. the metadata management service 552 of FIG. 5) that can
be communicatively coupled to public Internet 654 (e.g. public
Internet 554 of FIG. 5). Public Internet 654 can be communicatively
coupled to the NAT gateway 638 contained in the control plane VCN
616. The service gateway 636 contained in the control plane VCN 616
can be communicatively couple to cloud services 656 (e.g. cloud
services 556 of FIG. 5).
[0101] In some examples, the data plane VCN 618 can be contained in
the customer tenancy 621. In this case, the IaaS provider may
provide the control plane VCN 616 for each customer, and the IaaS
provider may, for each customer, set up a unique compute instance
644 that is contained in the service tenancy 619. Each compute
instance 644 may allow communication between the control plane VCN
616, contained in the service tenancy 619, and the data plane VCN
618 that is contained in the customer tenancy 621. The compute
instance 644 may allow resources, that are provisioned in the
control plane VCN 616 that is contained in the service tenancy 619,
to be deployed or otherwise used in the data plane VCN 618 that is
contained in the customer tenancy 621.
[0102] In other examples, the customer of the IaaS provider may
have databases that live in the customer tenancy 621. In this
example, the control plane VCN 616 can include the data plane
mirror app tier 640 that can include app subnet(s) 626. The data
plane mirror app tier 640 can reside in the data plane VCN 618, but
the data plane mirror app tier 640 may not live in the data plane
VCN 618. That is, the data plane mirror app tier 640 may have
access to the customer tenancy 621, but the data plane mirror app
tier 640 may not exist in the data plane VCN 618 or be owned or
operated by the customer of the IaaS provider. The data plane
mirror app tier 640 may be configured to make calls to the data
plane VCN 618 but may not be configured to make calls to any entity
contained in the control plane VCN 616. The customer may desire to
deploy or otherwise use resources in the data plane VCN 618 that
are provisioned in the control plane VCN 616, and the data plane
mirror app tier 640 can facilitate the desired deployment, or other
usage of resources, of the customer.
[0103] In some embodiments, the customer of the IaaS provider can
apply filters to the data plane VCN 618. In this embodiment, the
customer can determine what the data plane VCN 618 can access, and
the customer may restrict access to public Internet 654 from the
data plane VCN 618. The IaaS provider may not be able to apply
filters or otherwise control access of the data plane VCN 618 to
any outside networks or databases. Applying filters and controls by
the customer onto the data plane VCN 618, contained in the customer
tenancy 621, can help isolate the data plane VCN 618 from other
customers and from public Internet 654.
[0104] In some embodiments, cloud services 656 can be called by the
service gateway 636 to access services that may not exist on public
Internet 654, on the control plane VCN 616, or on the data plane
VCN 618. The connection between cloud services 656 and the control
plane VCN 616 or the data plane VCN 618 may not be live or
continuous. Cloud services 656 may exist on a different network
owned or operated by the IaaS provider. Cloud services 656 may be
configured to receive calls from the service gateway 636 and may be
configured to not receive calls from public Internet 654. Some
cloud services 656 may be isolated from other cloud services 656,
and the control plane VCN 616 may be isolated from cloud services
656 that may not be in the same region as the control plane VCN
616. For example, the control plane VCN 616 may be located in
"Region 1," and cloud service "Deployment 5," may be located in
Region 1 and in "Region 2." If a call to Deployment 5 is made by
the service gateway 636 contained in the control plane VCN 616
located in Region 1, the call may be transmitted to Deployment 5 in
Region 1. In this example, the control plane VCN 616, or Deployment
5 in Region 1, may not be communicatively coupled to, or otherwise
in communication with, Deployment 5 in Region 2.
[0105] FIG. 7 is a block diagram 700 illustrating another example
pattern of an IaaS architecture, according to at least one
embodiment. Service operators 702 (e.g. service operators 502 of
FIG. 5) can be communicatively coupled to a secure host tenancy 704
(e.g. the secure host tenancy 504 of FIG. 5) that can include a
virtual cloud network (VCN) 706 (e.g. the VCN 506 of FIG. 5) and a
secure host subnet 708 (e.g. the secure host subnet 508 of FIG. 5).
The VCN 706 can include an LPG 710 (e.g. the LPG 510 of FIG. 5)
that can be communicatively coupled to an SSH VCN 712 (e.g. the SSH
VCN 512 of FIG. 5) via an LPG 710 contained in the SSH VCN 712. The
SSH VCN 712 can include an SSH subnet 714 (e.g. the SSH subnet 514
of FIG. 5), and the SSH VCN 712 can be communicatively coupled to a
control plane VCN 716 (e.g. the control plane VCN 516 of FIG. 5)
via an LPG 710 contained in the control plane VCN 716 and to a data
plane VCN 718 (e.g. the data plane 518 of FIG. 5) via an LPG 710
contained in the data plane VCN 718. The control plane VCN 716 and
the data plane VCN 718 can be contained in a service tenancy 719
(e.g. the service tenancy 519 of FIG. 5).
[0106] The control plane VCN 716 can include a control plane DMZ
tier 720 (e.g. the control plane DMZ tier 520 of FIG. 5) that can
include load balancer (LB) subnet(s) 722 (e.g. LB subnet(s) 522 of
FIG. 5), a control plane app tier 724 (e.g. the control plane app
tier 524 of FIG. 5) that can include app subnet(s) 726 (e.g.
similar to app subnet(s) 526 of FIG. 5), a control plane data tier
728 (e.g. the control plane data tier 528 of FIG. 5) that can
include DB subnet(s) 730. The LB subnet(s) 722 contained in the
control plane DMZ tier 720 can be communicatively coupled to the
app subnet(s) 726 contained in the control plane app tier 724 and
to an Internet gateway 734 (e.g. the Internet gateway 534 of FIG.
5) that can be contained in the control plane VCN 716, and the app
subnet(s) 726 can be communicatively coupled to the DB subnet(s)
730 contained in the control plane data tier 728 and to a service
gateway 736 (e.g. the service gateway of FIG. 5) and a network
address translation (NAT) gateway 738 (e.g. the NAT gateway 538 of
FIG. 5). The control plane VCN 716 can include the service gateway
736 and the NAT gateway 738.
[0107] The data plane VCN 718 can include a data plane app tier 746
(e.g. the data plane app tier 546 of FIG. 5), a data plane DMZ tier
748 (e.g. the data plane DMZ tier 548 of FIG. 5), and a data plane
data tier 750 (e.g. the data plane data tier 550 of FIG. 5). The
data plane DMZ tier 748 can include LB subnet(s) 722 that can be
communicatively coupled to trusted app subnet(s) 760 and untrusted
app subnet(s) 762 of the data plane app tier 746 and the Internet
gateway 734 contained in the data plane VCN 718. The trusted app
subnet(s) 760 can be communicatively coupled to the service gateway
736 contained in the data plane VCN 718, the NAT gateway 738
contained in the data plane VCN 718, and DB subnet(s) 730 contained
in the data plane data tier 750. The untrusted app subnet(s) 762
can be communicatively coupled to the service gateway 736 contained
in the data plane VCN 718 and DB subnet(s) 730 contained in the
data plane data tier 750. The data plane data tier 750 can include
DB subnet(s) 730 that can be communicatively coupled to the service
gateway 736 contained in the data plane VCN 718.
[0108] The untrusted app subnet(s) 762 can include one or more
primary VNICs 764(1)-(N) that can be communicatively coupled to
tenant virtual machines (VMs) 766(1)-(N). Each tenant VM 766(1)-(N)
can be communicatively coupled to a respective app subnet
767(1)-(N) that can be contained in respective container egress
VCNs 768(1)-(N) that can be contained in respective customer
tenancies 770(1)-(N). Respective secondary VNICs 772(1)-(N) can
facilitate communication between the untrusted app subnet(s) 762
contained in the data plane VCN 718 and the app subnet contained in
the container egress VCNs 768(1)-(N). Each container egress VCNs
768(1)-(N) can include a NAT gateway 738 that can be
communicatively coupled to public Internet 754 (e.g. public
Internet 554 of FIG. 5).
[0109] The Internet gateway 734 contained in the control plane VCN
716 and contained in the data plane VCN 718 can be communicatively
coupled to a metadata management service 752 (e.g. the metadata
management system 552 of FIG. 5) that can be communicatively
coupled to public Internet 754. Public Internet 754 can be
communicatively coupled to the NAT gateway 738 contained in the
control plane VCN 716 and contained in the data plane VCN 718. The
service gateway 736 contained in the control plane VCN 716 and
contained in the data plane VCN 718 can be communicatively couple
to cloud services 756.
[0110] In some embodiments, the data plane VCN 718 can be
integrated with customer tenancies 770. This integration can be
useful or desirable for customers of the IaaS provider in some
cases such as a case that may desire support when executing code.
The customer may provide code to run that may be destructive, may
communicate with other customer resources, or may otherwise cause
undesirable effects. In response to this, the IaaS provider may
determine whether to run code given to the IaaS provider by the
customer.
[0111] In some examples, the customer of the IaaS provider may
grant temporary network access to the IaaS provider and request a
function to be attached to the data plane tier app 746. Code to run
the function may be executed in the VMs 766(1)-(N), and the code
may not be configured to run anywhere else on the data plane VCN
718. Each VM 766(1)-(N) may be connected to one customer tenancy
770. Respective containers 771(1)-(N) contained in the VMs
766(1)-(N) may be configured to run the code. In this case, there
can be a dual isolation (e.g., the containers 771(1)-(N) running
code, where the containers 771(1)-(N) may be contained in at least
the VM 766(1)-(N) that are contained in the untrusted app subnet(s)
762), which may help prevent incorrect or otherwise undesirable
code from damaging the network of the IaaS provider or from
damaging a network of a different customer. The containers
771(1)-(N) may be communicatively coupled to the customer tenancy
770 and may be configured to transmit or receive data from the
customer tenancy 770. The containers 771(1)-(N) may not be
configured to transmit or receive data from any other entity in the
data plane VCN 718. Upon completion of running the code, the IaaS
provider may kill or otherwise dispose of the containers
771(1)-(N).
[0112] In some embodiments, the trusted app subnet(s) 760 may run
code that may be owned or operated by the IaaS provider. In this
embodiment, the trusted app subnet(s) 760 may be communicatively
coupled to the DB subnet(s) 730 and be configured to execute CRUD
operations in the DB subnet(s) 730. The untrusted app subnet(s) 762
may be communicatively coupled to the DB subnet(s) 730, but in this
embodiment, the untrusted app subnet(s) may be configured to
execute read operations in the DB subnet(s) 730. The containers
771(1)-(N) that can be contained in the VM 766(1)-(N) of each
customer and that may run code from the customer may not be
communicatively coupled with the DB subnet(s) 730.
[0113] In other embodiments, the control plane VCN 716 and the data
plane VCN 718 may not be directly communicatively coupled. In this
embodiment, there may be no direct communication between the
control plane VCN 716 and the data plane VCN 718. However,
communication can occur indirectly through at least one method. An
LPG 710 may be established by the IaaS provider that can facilitate
communication between the control plane VCN 716 and the data plane
VCN 718. In another example, the control plane VCN 716 or the data
plane VCN 718 can make a call to cloud services 756 via the service
gateway 736. For example, a call to cloud services 756 from the
control plane VCN 716 can include a request for a service that can
communicate with the data plane VCN 718.
[0114] FIG. 8 is a block diagram 800 illustrating another example
pattern of an IaaS architecture, according to at least one
embodiment. Service operators 802 (e.g. service operators 502 of
FIG. 5) can be communicatively coupled to a secure host tenancy 804
(e.g. the secure host tenancy 504 of FIG. 5) that can include a
virtual cloud network (VCN) 806 (e.g. the VCN 506 of FIG. 5) and a
secure host subnet 808 (e.g. the secure host subnet 508 of FIG. 5).
The VCN 806 can include an LPG 810 (e.g. the LPG 510 of FIG. 5)
that can be communicatively coupled to an SSH VCN 812 (e.g. the SSH
VCN 512 of FIG. 5) via an LPG 810 contained in the SSH VCN 812. The
SSH VCN 812 can include an SSH subnet 814 (e.g. the SSH subnet 514
of FIG. 5), and the SSH VCN 812 can be communicatively coupled to a
control plane VCN 816 (e.g. the control plane VCN 516 of FIG. 5)
via an LPG 810 contained in the control plane VCN 816 and to a data
plane VCN 818 (e.g. the data plane 518 of FIG. 5) via an LPG 810
contained in the data plane VCN 818. The control plane VCN 816 and
the data plane VCN 818 can be contained in a service tenancy 819
(e.g. the service tenancy 519 of FIG. 5).
[0115] The control plane VCN 816 can include a control plane DMZ
tier 820 (e.g. the control plane DMZ tier 520 of FIG. 5) that can
include LB subnet(s) 822 (e.g. LB subnet(s) 522 of FIG. 5), a
control plane app tier 824 (e.g. the control plane app tier 524 of
FIG. 5) that can include app subnet(s) 826 (e.g. app subnet(s) 526
of FIG. 5), a control plane data tier 828 (e.g. the control plane
data tier 528 of FIG. 5) that can include DB subnet(s) 830 (e.g. DB
subnet(s) 730 of FIG. 7). The LB subnet(s) 822 contained in the
control plane DMZ tier 820 can be communicatively coupled to the
app subnet(s) 826 contained in the control plane app tier 824 and
to an Internet gateway 834 (e.g. the Internet gateway 534 of FIG.
5) that can be contained in the control plane VCN 816, and the app
subnet(s) 826 can be communicatively coupled to the DB subnet(s)
830 contained in the control plane data tier 828 and to a service
gateway 836 (e.g. the service gateway of FIG. 5) and a network
address translation (NAT) gateway 838 (e.g. the NAT gateway 538 of
FIG. 5). The control plane VCN 816 can include the service gateway
836 and the NAT gateway 838.
[0116] The data plane VCN 818 can include a data plane app tier 846
(e.g. the data plane app tier 546 of FIG. 5), a data plane DMZ tier
848 (e.g. the data plane DMZ tier 548 of FIG. 5), and a data plane
data tier 850 (e.g. the data plane data tier 550 of FIG. 5). The
data plane DMZ tier 848 can include LB subnet(s) 822 that can be
communicatively coupled to trusted app subnet(s) 860 (e.g. trusted
app subnet(s) 760 of FIG. 7) and untrusted app subnet(s) 862 (e.g.
untrusted app subnet(s) 762 of FIG. 7) of the data plane app tier
846 and the Internet gateway 834 contained in the data plane VCN
818. The trusted app subnet(s) 860 can be communicatively coupled
to the service gateway 836 contained in the data plane VCN 818, the
NAT gateway 838 contained in the data plane VCN 818, and DB
subnet(s) 830 contained in the data plane data tier 850. The
untrusted app subnet(s) 862 can be communicatively coupled to the
service gateway 836 contained in the data plane VCN 818 and DB
subnet(s) 830 contained in the data plane data tier 850. The data
plane data tier 850 can include DB subnet(s) 830 that can be
communicatively coupled to the service gateway 836 contained in the
data plane VCN 818.
[0117] The untrusted app subnet(s) 862 can include primary VNICs
864(1)-(N) that can be communicatively coupled to tenant virtual
machines (VMs) 866(1)-(N) residing within the untrusted app
subnet(s) 862. Each tenant VM 866(1)-(N) can run code in a
respective container 867(1)-(N), and be communicatively coupled to
an app subnet 826 that can be contained in a data plane app tier
846 that can be contained in a container egress VCN 868. Respective
secondary VNICs 872(1)-(N) can facilitate communication between the
untrusted app subnet(s) 862 contained in the data plane VCN 818 and
the app subnet contained in the container egress VCN 868. The
container egress VCN can include a NAT gateway 838 that can be
communicatively coupled to public Internet 854 (e.g. public
Internet 554 of FIG. 5).
[0118] The Internet gateway 834 contained in the control plane VCN
816 and contained in the data plane VCN 818 can be communicatively
coupled to a metadata management service 852 (e.g. the metadata
management system 552 of FIG. 5) that can be communicatively
coupled to public Internet 854. Public Internet 854 can be
communicatively coupled to the NAT gateway 838 contained in the
control plane VCN 816 and contained in the data plane VCN 818. The
service gateway 836 contained in the control plane VCN 816 and
contained in the data plane VCN 818 can be communicatively couple
to cloud services 856.
[0119] In some examples, the pattern illustrated by the
architecture of block diagram 800 of FIG. 8 may be considered an
exception to the pattern illustrated by the architecture of block
diagram 700 of FIG. 7 and may be desirable for a customer of the
IaaS provider if the IaaS provider cannot directly communicate with
the customer (e.g., a disconnected region). The respective
containers 867(1)-(N) that are contained in the VMs 866(1)-(N) for
each customer can be accessed in real-time by the customer. The
containers 867(1)-(N) may be configured to make calls to respective
secondary VNICs 872(1)-(N) contained in app subnet(s) 826 of the
data plane app tier 846 that can be contained in the container
egress VCN 868. The secondary VNICs 872(1)-(N) can transmit the
calls to the NAT gateway 838 that may transmit the calls to public
Internet 854. In this example, the containers 867(1)-(N) that can
be accessed in real-time by the customer can be isolated from the
control plane VCN 816 and can be isolated from other entities
contained in the data plane VCN 818. The containers 867(1)-(N) may
also be isolated from resources from other customers.
[0120] In other examples, the customer can use the containers
867(1)-(N) to call cloud services 856. In this example, the
customer may run code in the containers 867(1)-(N) that requests a
service from cloud services 856. The containers 867(1)-(N) can
transmit this request to the secondary VNICs 872(1)-(N) that can
transmit the request to the NAT gateway that can transmit the
request to public Internet 854. Public Internet 854 can transmit
the request to LB subnet(s) 822 contained in the control plane VCN
816 via the Internet gateway 834. In response to determining the
request is valid, the LB subnet(s) can transmit the request to app
subnet(s) 826 that can transmit the request to cloud services 856
via the service gateway 836.
[0121] It should be appreciated that IaaS architectures 500, 600,
700, 800 depicted in the figures may have other components than
those depicted. Further, the embodiments shown in the figures are
only some examples of a cloud infrastructure system that may
incorporate an embodiment of the disclosure. In some other
embodiments, the IaaS systems may have more or fewer components
than shown in the figures, may combine two or more components, or
may have a different configuration or arrangement of
components.
[0122] In certain embodiments, the IaaS systems described herein
may include a suite of applications, middleware, and database
service offerings that are delivered to a customer in a
self-service, subscription-based, elastically scalable, reliable,
highly available, and secure manner. An example of such an IaaS
system is the Oracle Cloud Infrastructure (OCI) provided by the
present assignee.
[0123] FIG. 9 illustrates an example computer system 900, in which
various embodiments may be implemented such as the client device
described in connection with FIGS. 1-4. The system 900 may be used
to implement any of the computer systems described above. As shown
in the figure, computer system 900 includes a processing unit 904
that communicates with a number of peripheral subsystems via a bus
subsystem 902. These peripheral subsystems may include a processing
acceleration unit 906, an I/O subsystem 908, a storage subsystem
918 and a communications subsystem 924. Storage subsystem 918
includes tangible computer-readable storage media 922 and a system
memory 910.
[0124] Bus subsystem 902 provides a mechanism for letting the
various components and subsystems of computer system 900
communicate with each other as intended. Although bus subsystem 902
is shown schematically as a single bus, alternative embodiments of
the bus subsystem may utilize multiple buses. Bus subsystem 902 may
be any of several types of bus structures including a memory bus or
memory controller, a peripheral bus, and a local bus using any of a
variety of bus architectures. For example, such architectures may
include an Industry Standard Architecture (ISA) bus, Micro Channel
Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics
Standards Association (VESA) local bus, and Peripheral Component
Interconnect (PCI) bus, which can be implemented as a Mezzanine bus
manufactured to the IEEE P1386.1 standard.
[0125] Processing unit 904, which can be implemented as one or more
integrated circuits (e.g., a conventional microprocessor or
microcontroller), controls the operation of computer system 900.
One or more processors may be included in processing unit 904.
These processors may include single core or multicore processors.
In certain embodiments, processing unit 904 may be implemented as
one or more independent processing units 932 and/or 934 with single
or multicore processors included in each processing unit. In other
embodiments, processing unit 904 may also be implemented as a
quad-core processing unit formed by integrating two dual-core
processors into a single chip.
[0126] In various embodiments, processing unit 904 can execute a
variety of programs in response to program code and can maintain
multiple concurrently executing programs or processes. At any given
time, some or all of the program code to be executed can be
resident in processor(s) 904 and/or in storage subsystem 918.
Through suitable programming, processor(s) 904 can provide various
functionalities described above. Computer system 900 may
additionally include a processing acceleration unit 906, which can
include a digital signal processor (DSP), a special-purpose
processor, and/or the like.
[0127] I/O subsystem 908 may include user interface input devices
and user interface output devices. User interface input devices may
include a keyboard, pointing devices such as a mouse or trackball,
a touchpad or touch screen incorporated into a display, a scroll
wheel, a click wheel, a dial, a button, a switch, a keypad, audio
input devices with voice command recognition systems, microphones,
and other types of input devices. User interface input devices may
include, for example, motion sensing and/or gesture recognition
devices such as the Microsoft Kinect.RTM. motion sensor that
enables users to control and interact with an input device, such as
the Microsoft Xbox.RTM. 360 game controller, through a natural user
interface using gestures and spoken commands. User interface input
devices may also include eye gesture recognition devices such as
the Google Glass.RTM. blink detector that detects eye activity
(e.g., `blinking` while taking pictures and/or making a menu
selection) from users and transforms the eye gestures as input into
an input device (e.g., Google Glass.RTM.). Additionally, user
interface input devices may include voice recognition sensing
devices that enable users to interact with voice recognition
systems (e.g., Siri.RTM. navigator), through voice commands.
[0128] User interface input devices may also include, without
limitation, three dimensional (3D) mice, joysticks or pointing
sticks, gamepads and graphic tablets, and audio/visual devices such
as speakers, digital cameras, digital camcorders, portable media
players, webcams, image scanners, fingerprint scanners, barcode
reader 3D scanners, 3D printers, laser rangefinders, and eye gaze
tracking devices. Additionally, user interface input devices may
include, for example, medical imaging input devices such as
computed tomography, magnetic resonance imaging, position emission
tomography, medical ultrasonography devices. User interface input
devices may also include, for example, audio input devices such as
MIDI keyboards, digital musical instruments and the like.
[0129] User interface output devices may include a display
subsystem, indicator lights, or non-visual displays such as audio
output devices, etc. The display subsystem may be a cathode ray
tube (CRT), a flat-panel device, such as that using a liquid
crystal display (LCD) or plasma display, a projection device, a
touch screen, and the like. In general, use of the term "output
device" is intended to include all possible types of devices and
mechanisms for outputting information from computer system 900 to a
user or other computer. For example, user interface output devices
may include, without limitation, a variety of display devices that
visually convey text, graphics and audio/video information such as
monitors, printers, speakers, headphones, automotive navigation
systems, plotters, voice output devices, and modems.
[0130] Computer system 900 may comprise a storage subsystem 918
that comprises software elements, shown as being currently located
within a system memory 910. System memory 910 may store program
instructions that are loadable and executable on processing unit
904, as well as data generated during the execution of these
programs.
[0131] Depending on the configuration and type of computer system
900, system memory 910 may be volatile (such as random access
memory (RAM)) and/or non-volatile (such as read-only memory (ROM),
flash memory, etc.) The RAM typically contains data and/or program
modules that are immediately accessible to and/or presently being
operated and executed by processing unit 904. In some
implementations, system memory 910 may include multiple different
types of memory, such as static random access memory (SRAM) or
dynamic random access memory (DRAM). In some implementations, a
basic input/output system (BIOS), containing the basic routines
that help to transfer information between elements within computer
system 900, such as during start-up, may typically be stored in the
ROM. By way of example, and not limitation, system memory 910 also
illustrates application programs 912, which may include client
applications, Web browsers, mid-tier applications, relational
database management systems (RDBMS), etc., program data 914, and an
operating system 916. By way of example, operating system 916 may
include various versions of Microsoft Windows.RTM., Apple
Macintosh.RTM., and/or Linux operating systems, a variety of
commercially-available UNIX.RTM. or UNIX-like operating systems
(including without limitation the variety of GNU/Linux operating
systems, the Google Chrome.RTM. OS, and the like) and/or mobile
operating systems such as iOS, Windows.RTM. Phone, Android.RTM. OS,
BlackBerry.RTM. 9 OS, and Palm.RTM. OS operating systems.
[0132] Storage subsystem 918 may also provide a tangible
computer-readable storage medium for storing the basic programming
and data constructs that provide the functionality of some
embodiments. Software (programs, code modules, instructions) that
when executed by a processor provide the functionality described
above may be stored in storage subsystem 918. These software
modules or instructions may be executed by processing unit 904.
Storage subsystem 918 may also provide a repository for storing
data used in accordance with the present disclosure.
[0133] Storage subsystem 900 may also include a computer-readable
storage media reader 920 that can further be connected to
computer-readable storage media 922. Together and, optionally, in
combination with system memory 910, computer-readable storage media
922 may comprehensively represent remote, local, fixed, and/or
removable storage devices plus storage media for temporarily and/or
more permanently containing, storing, transmitting, and retrieving
computer-readable information.
[0134] Computer-readable storage media 922 containing code, or
portions of code, can also include any appropriate media known or
used in the art, including storage media and communication media,
such as but not limited to, volatile and non-volatile, removable
and non-removable media implemented in any method or technology for
storage and/or transmission of information. This can include
tangible computer-readable storage media such as RAM, ROM,
electronically erasable programmable ROM (EEPROM), flash memory or
other memory technology, CD-ROM, digital versatile disk (DVD), or
other optical storage, magnetic cassettes, magnetic tape, magnetic
disk storage or other magnetic storage devices, or other tangible
computer readable media. This can also include nontangible
computer-readable media, such as data signals, data transmissions,
or any other medium which can be used to transmit the desired
information and which can be accessed by computing system 900.
[0135] By way of example, computer-readable storage media 922 may
include a hard disk drive that reads from or writes to
non-removable, nonvolatile magnetic media, a magnetic disk drive
that reads from or writes to a removable, nonvolatile magnetic
disk, and an optical disk drive that reads from or writes to a
removable, nonvolatile optical disk such as a CD ROM, DVD, and
Blu-Ray.RTM. disk, or other optical media. Computer-readable
storage media 922 may include, but is not limited to, Zip.RTM.
drives, flash memory cards, universal serial bus (USB) flash
drives, secure digital (SD) cards, DVD disks, digital video tape,
and the like. Computer-readable storage media 922 may also include,
solid-state drives (SSD) based on non-volatile memory such as
flash-memory based SSDs, enterprise flash drives, solid state ROM,
and the like, SSDs based on volatile memory such as solid state
RAM, dynamic RAM, static RAM, DRAM-based SSDs, magnetoresistive RAM
(MRAM) SSDs, and hybrid SSDs that use a combination of DRAM and
flash memory based SSDs. The disk drives and their associated
computer-readable media may provide non-volatile storage of
computer-readable instructions, data structures, program modules,
and other data for computer system 900.
[0136] Communications subsystem 924 provides an interface to other
computer systems and networks. Communications subsystem 924 serves
as an interface for receiving data from and transmitting data to
other systems from computer system 900. For example, communications
subsystem 924 may enable computer system 900 to connect to one or
more devices via the Internet. In some embodiments communications
subsystem 924 can include radio frequency (RF) transceiver
components for accessing wireless voice and/or data networks (e.g.,
using cellular telephone technology, advanced data network
technology, such as 3G, 4G or EDGE (enhanced data rates for global
evolution), WiFi (IEEE 802.11 family standards, or other mobile
communication technologies, or any combination thereof), global
positioning system (GPS) receiver components, and/or other
components. In some embodiments communications subsystem 924 can
provide wired network connectivity (e.g., Ethernet) in addition to
or instead of a wireless interface.
[0137] In some embodiments, communications subsystem 924 may also
receive input communication in the form of structured and/or
unstructured data feeds 926, event streams 928, event updates 930,
and the like on behalf of one or more users who may use computer
system 900.
[0138] By way of example, communications subsystem 924 may be
configured to receive data feeds 926 in real-time from users of
social networks and/or other communication services such as
Twitter.RTM. feeds, Facebook.RTM. updates, web feeds such as Rich
Site Summary (RSS) feeds, and/or real-time updates from one or more
third party information sources.
[0139] Additionally, communications subsystem 924 may also be
configured to receive data in the form of continuous data streams,
which may include event streams 928 of real-time events and/or
event updates 930, that may be continuous or unbounded in nature
with no explicit end. Examples of applications that generate
continuous data may include, for example, sensor data applications,
financial tickers, network performance measuring tools (e.g.
network monitoring and traffic management applications),
clickstream analysis tools, automobile traffic monitoring, and the
like.
[0140] Communications subsystem 924 may also be configured to
output the structured and/or unstructured data feeds 926, event
streams 928, event updates 930, and the like to one or more
databases that may be in communication with one or more streaming
data source computers coupled to computer system 900.
[0141] Computer system 900 can be one of various types, including a
handheld portable device (e.g., an iPhone.RTM. cellular phone, an
iPad.RTM. computing tablet, a PDA), a wearable device (e.g., a
Google Glass.RTM. head mounted display), a PC, a workstation, a
mainframe, a kiosk, a server rack, or any other data processing
system.
[0142] Due to the ever-changing nature of computers and networks,
the description of computer system 900 depicted in the figure is
intended only as a specific example. Many other configurations
having more or fewer components than the system depicted in the
figure are possible. For example, customized hardware might also be
used and/or particular elements might be implemented in hardware,
firmware, software (including applets), or a combination. Further,
connection to other computing devices, such as network input/output
devices, may be employed. Based on the disclosure and teachings
provided herein, a person of ordinary skill in the art will
appreciate other ways and/or methods to implement the various
embodiments.
[0143] Although specific embodiments have been described, various
modifications, alterations, alternative constructions, and
equivalents are also encompassed within the scope of the
disclosure. Embodiments are not restricted to operation within
certain specific data processing environments, but are free to
operate within a plurality of data processing environments.
Additionally, although embodiments have been described using a
particular series of transactions and steps, it should be apparent
to those skilled in the art that the scope of the present
disclosure is not limited to the described series of transactions
and steps. Various features and aspects of the above-described
embodiments may be used individually or jointly.
[0144] Further, while embodiments have been described using a
particular combination of hardware and software, it should be
recognized that other combinations of hardware and software are
also within the scope of the present disclosure. Embodiments may be
implemented only in hardware, or only in software, or using
combinations thereof. The various processes described herein can be
implemented on the same processor or different processors in any
combination. Accordingly, where components or modules are described
as being configured to perform certain operations, such
configuration can be accomplished, e.g., by designing electronic
circuits to perform the operation, by programming programmable
electronic circuits (such as microprocessors) to perform the
operation, or any combination thereof. Processes can communicate
using a variety of techniques including but not limited to
conventional techniques for inter process communication, and
different pairs of processes may use different techniques, or the
same pair of processes may use different techniques at different
times.
[0145] The specification and drawings are, accordingly, to be
regarded in an illustrative rather than a restrictive sense. It
will, however, be evident that additions, subtractions, deletions,
and other modifications and changes may be made thereunto without
departing from the broader spirit and scope as set forth in the
claims. Thus, although specific disclosure embodiments have been
described, these are not intended to be limiting. Various
modifications and equivalents are within the scope of the following
claims.
[0146] The use of the terms "a" and "an" and "the" and similar
referents in the context of describing the disclosed embodiments
(especially in the context of the following claims) are to be
construed to cover both the singular and the plural, unless
otherwise indicated herein or clearly contradicted by context. The
terms "comprising," "having," "including," and "containing" are to
be construed as open-ended terms (i.e., meaning "including, but not
limited to,") unless otherwise noted. The term "connected" is to be
construed as partly or wholly contained within, attached to, or
joined together, even if there is something intervening. Recitation
of ranges of values herein are merely intended to serve as a
shorthand method of referring individually to each separate value
falling within the range, unless otherwise indicated herein and
each separate value is incorporated into the specification as if it
were individually recited herein. All methods described herein can
be performed in any suitable order unless otherwise indicated
herein or otherwise clearly contradicted by context. The use of any
and all examples, or exemplary language (e.g., "such as") provided
herein, is intended merely to better illuminate embodiments and
does not pose a limitation on the scope of the disclosure unless
otherwise claimed. No language in the specification should be
construed as indicating any non-claimed element as essential to the
practice of the disclosure.
[0147] Disjunctive language such as the phrase "at least one of X,
Y, or Z," unless specifically stated otherwise, is intended to be
understood within the context as used in general to present that an
item, term, etc., may be either X, Y, or Z, or any combination
thereof (e.g., X, Y, and/or Z). Thus, such disjunctive language is
not generally intended to, and should not, imply that certain
embodiments require at least one of X, at least one of Y, or at
least one of Z to each be present.
[0148] Preferred embodiments of this disclosure are described
herein, including the best mode known for carrying out the
disclosure. Variations of those preferred embodiments may become
apparent to those of ordinary skill in the art upon reading the
foregoing description. Those of ordinary skill should be able to
employ such variations as appropriate and the disclosure may be
practiced otherwise than as specifically described herein.
Accordingly, this disclosure includes all modifications and
equivalents of the subject matter recited in the claims appended
hereto as permitted by applicable law. Moreover, any combination of
the above-described elements in all possible variations thereof is
encompassed by the disclosure unless otherwise indicated
herein.
[0149] All references, including publications, patent applications,
and patents, cited herein are hereby incorporated by reference to
the same extent as if each reference were individually and
specifically indicated to be incorporated by reference and were set
forth in its entirety herein.
[0150] In the foregoing specification, aspects of the disclosure
are described with reference to specific embodiments thereof, but
those skilled in the art will recognize that the disclosure is not
limited thereto. Various features and aspects of the
above-described disclosure may be used individually or jointly.
Further, embodiments can be utilized in any number of environments
and applications beyond those described herein without departing
from the broader spirit and scope of the specification. The
specification and drawings are, accordingly, to be regarded as
illustrative rather than restrictive.
* * * * *