Ceph and Grafana dashboards broken after upgrade, Prometheus "is not accessible" with 404 error.

Issue

• ceph and grafana dashboards broken after upgrading to RHCS 5.

• Grafana still keeps old datasource as the default, after update from RHCS4 to RHCS5

• After upgrading RHCS 4 to RHCS 5, none of the graphs are visible in ceph-dashboard.

• Ceph dashboard is complaining every second that http://<prometheus>:9095/api/v1 is not accessible.

• After upgrading from RHCS 4 to RHCS 5, getting 404 error in the dashboard while connecting to Prometheus.