Additional Metrics

[elubow]

This pull request includes laying out all the metrics for:

• masters
• agents
• /monitor/statistics

[philipnrmn]

Awesome work, thanks @elubow.

[StephanErb]

-1 on this. This will break every existing deployment that uses this exporter.

If you want to make changes like this, please provide a metric relabeling config so that users can seamlessly migrate all dashboards and alerting configurations.

[philipnrmn]

@StephanErb how so?

[elubow]

I only had 1 existing deployment to test it on and it didn't break it. I'm also following this up with another PR which has much better error handling.

[StephanErb]

For example, the metric mem_rss_bytes was renamed to mesos_agent_mem_rss_bytes. I totally agree that the new name is better, but it is very hard to deploy into a production environment with dozens of dashboards and alert configurations.

Normally changes like this are done by providing a metric relabelling config, so that both metrics can co-exist at the same time. For example, there is currently a similar issue in the Prometheus node exporter prometheus/node_exporter#830

[StephanErb]

I did not intend to sound so harsh. Besides of the breaking naming change this contribution looks great! I am sure we can figure it out :)

[elubow]

Part of the issue here is that some of the metrics aren't even being collected all the time. For instance threads is a really generic name. So I'm not sure how a relabel would help there as it's so generic it might actually make things worse depending on the environment. I can certainly create a diff of metric names. But that also won't account for metrics that have migrated to submetrics with labels. At least I couldn't see a way to handle that scenario from prometheus/node_exporter#830. Any solution we come up with would be half-baked at best.

Also, it's only harsh until constructive feedback transpires :) Point taken, but we definitely have some issues that I don't see a path to resolution for.

[philipnrmn]

Not at all harsh - this is very fair criticism, I was trigger-happy on the merge. I'll make sure we get a relabelling config in soon.