Add a new metric that tracks the coordinator changes per cluster

[johscheuer]

Description

Fixes: #782

Type of change

• New feature (non-breaking change which adds functionality)

Discussion

I moved the metrics code a bit around for better usability.

Testing

I did a manual test, right now we don't have any specific e2e tests for the metrics:

bash-5.1$ curl -s localhost:8080/metrics | grep coordinator
# HELP fdb_operator_coordinator_changes_total Total number of coordinator changes performed on the cluster
# TYPE fdb_operator_coordinator_changes_total counter
fdb_operator_coordinator_changes_total{name="jdev",namespace="jscheuermann"} 2
bash-5.1$ curl -s localhost:8080/metrics | grep coordinator
# HELP fdb_operator_coordinator_changes_total Total number of coordinator changes performed on the cluster
# TYPE fdb_operator_coordinator_changes_total counter
fdb_operator_coordinator_changes_total{name="jdev",namespace="jscheuermann"} 3

Documentation

Follow-up

[foundationdb-ci]

Result of fdb-kubernetes-operator-pr on Linux RHEL 9

• Commit ID: 6a8d65f
• Duration 1:58:17
• Result: ✅ SUCCEEDED
• Error: N/A
• Build Log terminal output (available for 30 days)
• Build Workspace zip file of the working directory (available for 30 days)

[nicmorales9]

this does seem nice! LGTM

[foundationdb-ci]

Result of fdb-kubernetes-operator-pr on Linux RHEL 9

• Commit ID: a4ef837
• Duration 2:44:06
• Result: ❌ FAILED
• Error: Error while executing command: if $fail_test; then exit 1; fi. Reason: exit status 1
• Build Log terminal output (available for 30 days)
• Build Workspace zip file of the working directory (available for 30 days)

[foundationdb-ci]

Result of fdb-kubernetes-operator-pr on Linux RHEL 9

• Commit ID: a4ef837
• Duration 1:56:11
• Result: ✅ SUCCEEDED
• Error: N/A
• Build Log terminal output (available for 30 days)
• Build Workspace zip file of the working directory (available for 30 days)