Custom metric for agent's free memory

[jeznag]

Would be useful to expose free memory as per https://github.com/buildkite/agent/issues/133

The concern there seemed to be that the buildkite agent should be platform independent. The Elastic CI stack is not platform independent and therefore would be great to provide free RAM metrics via cloudwatch.

I'm currently trying to understand whether my build jobs are CPU constrained or memory constrained and therefore access to RAM stats would be useful.

[lox]

Would something like https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/mon-scripts.html on the instances help?

[jeznag]

That would be ideal.

[lox]

If you felt inclined to submit a PR, we'd be very receptive!

[keithduncan]

While looking into something else I found the CloudWatch Agent can be configured to report metrics including memory. In the meantime this configuration could be added using the BootstrapScriptUrl and the agent reloaded/restarted to pick up the change.