We should introduce a new "retentionSize" field under the prometheus key. To keep things backward compatible, the existing "retention" field applies to time retention only.

apiVersion: v1
kind: ConfigMap
metadata:
  name: user-workload-monitoring-config
  namespace: openshift-user-workload-monitoring
data:
  config.yaml: |
    prometheus:

      retention: 1y

      retentionSize: 10Gi

For details see MON-2216.

DoD

• User can configure size-based retention in the CMO configuration which is applied to the UWM Prometheus.