Telemetry support

[keeganwitt]

SPIRE Controller Manager should support telemetry integration to publish metrics about it's performance, similar to SPIRE.

[faisal-memon]

@keeganwitt More visibility is good. Any specific metrics youd like to see?

[kfox1111]

Heh. Thought we were talking about spiffe-helper... Sorry.

Some random musings..... generally anything that would help a sysadmin determine if something is malfunctioning and how badly...

• How many times the certificate has been refreshed since the process started
• How many failed refreshes have there been since the process started
• Is the certificate currently valid
• count of failed execs since the process started

[keeganwitt]

A few that come to mind are

1. How many new entries are being created? Maybe some metadata about them (Was it static? Was it federated? What K8s namespace?)
2. How many entries are deleted?
3. Metrics for any failures

[kfox1111]

Maybe how long ago was the last successful sync time.