Epic Goal

• Cluster admins want to configure the retention size for their metrics.

Why is this important?

• While it is possible to define how long metrics should be retained on disk, it's not possible to tell the cluster monitoring operator how much data it should keep. For OSD/ROSA in particular, it would facilitate the management of the fleet if the retention size could be configured based on the persistent volume size because it would avoid issues with the storage getting full and monitoring being down when too many metrics are produced.

Scenarios

• As a cluster admin, I want to define the maximum amount of data to be retained on the persistent volume.

Acceptance Criteria

• CI - MUST be running successfully with tests automated
• Release Technical Enablement - Provide necessary release enablement details and documents.
• The cluster-monitoring-config config and the user-workload-monitoring-config configmap allow to configure the retention size for
  • Prometheus (Platform and UWM)
  • Thanos Ruler (to be confirmed)
• Proper validation is in place preventing bad user inputs from breaking the stack.

Dependencies (internal and external)

1. Thanos ruler doesn't support retention size (only retention time).

Previous Work (Optional):

1. None

Open questions::

1. None

Docs:

TBD