Comment 4 for bug 1838460

In standalone scenario1, we are seeing the same issue:
https://zuul.opendev.org/t/openstack/build/ca8e1f55314941a4941d616cb1521a1b/log/logs/undercloud/home/zuul/standalone_deploy.log.txt.gz#4922

2019-08-23 05:20:46 | "Friday 23 August 2019 05:20:45 +0000 (0:00:00.120) 0:00:27.869 ********* ",

2019-08-23 05:20:46 | "TASK [ceph-validate : fail if [grafana-server] group doesn't exist] ************",

2019-08-23 05:20:46 | "Friday 23 August 2019 05:20:46 +0000 (0:00:00.354) 0:00:28.224 ********* ",

2019-08-23 05:20:46 | "fatal: [standalone]: FAILED! => changed=false ",

2019-08-23 05:20:46 | " msg: you must add a [grafana-server] group and add at least one node.",

2019-08-23 05:20:46 | "NO MORE HOSTS LEFT ************************************************************

Probable cause: https://review.opendev.org/#/c/677705/