If you want to use a non-default root certificate for object storage connections, register it in ConfigMap.

$ oc create configmap storage-cacert --from-file=ca.crt=storage-ca.pem -n my-namespace

When using the parameter (repo-gcs-key) of pgBackRest, register the GCS repository key in Secret.

$ oc create secret generic storage-key-secret --from-file=key.json=storage-key.json -n my-namespace