Description

• A note must be added to the documentation advising against using "cluster" and "managed_cluster" as externalLabels.
  • https://docs.openshift.com/container-platform/4.13/monitoring/configuring-the-monitoring-stack.html#attaching-additional-labels-to-your-time-series-and-alerts_configuring-the-monitoring-stack
• Setting "cluster" as externalLabels for Prometheus causes issues where users are unable to see data in the developer dashboard. If the ACM operator is installed with a version above 2.6.3, then setting externalLabels as "managed_cluster" also produces the same issue.
  • https://access.redhat.com/solutions/6981407
• It is necessary to add such note as to prevent such issues with developer dashboard.