Tested with 4.4.0-0.nightly-2020-02-23-191320, in order to create PVC before Prometheus, do
# while true; do oc -n openshift-monitoring delete prometheus/k8s; done
then use cluster-monitoring-config configmap to create PVCs, after all the PVCs are created, stop the first command, check the cluster-monitoring-operator pod's log, there is not "sync "openshift-monitoring/cluster-monitoring-config" failed: running task Updating Prometheus-k8s failed: reconciling Prometheus object failed: creating Prometheus object failed: Prometheus.monitoring.coreos.com "k8s" is invalid: spec.storage.volumeClaimTemplate.metadata.creationTimestamp: Invalid value: "null": spec.storage.volumeClaimTemplate.metadata.creationTimestamp in body must be of type string: "null" " error and the prometheus resource is created
# oc -n openshift-monitoring get prometheus/k8s
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.