Skip Task resource accounting for Fargate 1.3.0 launch type

[prateekchaudhry]

Summary

ECS backend resource accounting can be different for Fargate (1.3.0) than for ECS/EC2 or ECS-Anywhere. This can cause issues with task resource accounting in ECS Agent, if it is not in sync with backend accounting. This behavior can be turned off for Fargate tasks and all resource availability can be delegated to Fargate backend instead.

Implementation details

• ACS Payload has field LaunchType which takes value FARGATE for Fargate tasks. For such tasks, do not queue them up and launch them up straightaway. Their resources never get accounted in HostResourceManager.
• HostResourceManager release resources is not a problem as it is an idempotent release. If a task does not exist in HostResourceManager's accounting, this operation will be a no-op.

Testing

• Added Integ tests to validate HostResourceManager still consumes resources for non fargate tasks, and does not consume resources for fargate tasks
• Manual testing
  Both EC2 and External -

  • Queued 1 task after the other, enough memory available for 2nd task

    • 2nd task starts without waiting for 1st task to stopped

  • Queued 1 task, Stopped it with stop timeout of 30s, started new task with conflicted resource (CPU)

    • 2nd task starts after 1st task goes to stopped

New tests cover the changes:
Yes

Description for the changelog

Skip Task resource accounting for Fargate 1.3.0 launch type

Licensing

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.