Support Dockerfile HEALTHCHECK of agent

[jhmartin]

Docker 1.12 and newer supports a HEALTHCHECK directive that allows the docker daemon to detect the health of an application inside a container. Please consider adding one to the agent Dockerfile.

Docs: https://docs.docker.com/engine/reference/builder/#healthcheck

[samuelkarp]

Hi @jhmartin, thanks for reaching out. This issue is a duplicate of #534, and discussion is happening there. If you have any comments to add to the discussion, please add it on #534. Thanks!

[jhmartin]

@samuelkarp It is different. #534 suggests allowing the ecs-agent to use the HEALTHCHECK output in place of the A/ELB healthchecks to detect the state of containers managed by ECS.

This issue is for the ECS to include a HEALTHCHECK directive for itself.

[samuelkarp]

Ah, I think I missed that in your description. My apologies for the premature close.

The agent's Dockerfile is here if you're interested in making a contribution.

[cyastella]

Closing issue since a new set of amis have been released and can be tracked here
The agent v1.33 here now support this enhancement.