Clean unused monitoring service additionalLabels value

[rdettai]

A quick search in the repo didn't give any match for serviceMonitor.additionalLabels:

• introduced in a buggy way in Refactoring labels: support for additional labels and monitoring #27
• cleanup up partially a few months later in 7132cff

[nlamirault]

If you remove the additional labels for ServiceMonitor, how do you specify to the Prometheus Operator to find the Quickwit Service Monitor?

With a Prometheus Operator configured like that:

prometheusSpec:
      ...
      ruleNamespaceSelector: {}
      ruleSelector:
        matchLabels:
          observability: infra
      serviceMonitorSelector:
        matchLabels:
          observability: infra
      serviceMonitorNamespaceSelector: {}
      podMonitorSelector:
        matchLabels:
          observability: infra
      podMonitorNamespaceSelector: {}
      probeSelector:
        matchLabels:
          observability: infra
      probeNamespaceSelector: {}

we can set the Quickwit ServiceMonitor like that:

serviceMonitor:
  enabled: true
  additionalLabels:
    observability: infra

Without the additional labels, the ServiceMonitor will not be find by the Prometheus Operator. Then Prometheus operated by the Prometheus Operator don't monitor Quickwit :(

See: #80

[rdettai]

Thanks for giving some context @nlamirault. The intent here was to clean up a setting that wasn't working properly, but fixing it is obviously better! Closing this in favor of #80