Comment 2 for bug 2042891

I took some time to look into this in another occasion.

[cos prometheus side]

- honor_labels: true
  job_name: juju_ceph-build-plus_415bb55c_ceph-mon_prometheus_scrape-0
  metrics_path: /metrics
  relabel_configs:
  - regex: (.*)
    separator: _
    source_labels:
    - juju_model
    - juju_model_uuid
    - juju_application
    - juju_unit
    target_label: instance
  scrape_interval: 15s
  static_configs:
  - labels:
      juju_application: ceph-mon
      juju_charm: ceph-mon
      juju_model: ceph-build-plus
      juju_model_uuid: 415bb55c-341e-4aa4-8851-679bec38c471
      juju_unit: ceph-mon/0
    targets:
    - <IP_ADDRESS_OF_CEPH_MON_0>:9283

[ceph-mon/0]

$ sudo ceph mgr module ls
MODULE
balancer on (always on)
crash on (always on)
devicehealth on (always on)
orchestrator on (always on)
pg_autoscaler on (always on)
progress on (always on)
rbd_support on (always on)
status on (always on)
telemetry on (always on)
volumes on (always on)
dashboard on
iostat on
nfs on
restful on
alerts -
...
prometheus -

[juju show-unit ceph-mon/0]

  - relation-id: 30
    endpoint: metrics-endpoint
    cross-model: true
    related-endpoint: configurable-scrape-jobs
    application-data: {}
    related-units:
      cos-prometheus-scrape-config/0:
        in-scope: true
        data:
          egress-subnets: <cluster IP of service/prometheus-scrape-config>/32
          ingress-address: <cluster IP of service/prometheus-scrape-config>
          private-address: <cluster IP of service/prometheus-scrape-config>

^^^ this looks the same as another environment where there is no race condition.