* Description of problem:

Running 'purge-docker-cluster.yml' playbook to purge a Containerized Ceph cluster setup, fails at "TASK [ensure rbd devices are unmapped]".
The task tries to execute 'rbdmap unmap-all', however the 'rbdmap' command isn't available on the host machine.

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2019-10-24 XX:XX:XX,172 p=2133 u=ceph |  fatal: [host0]: FAILED! => {"changed": false, "cmd": "rbdmap unmap-all", "msg": "[Errno 2] No such file or directory", "rc": 2}
2019-10-24 XX:XX:XX,247 p=2133 u=ceph |  fatal: [host2]: FAILED! => {"changed": false, "cmd": "rbdmap unmap-all", "msg": "[Errno 2] No such file or directory", "rc": 2}
2019-10-24 XX:XX:XX,333 p=2133 u=ceph |  fatal: [host1]: FAILED! => {"changed": false, "cmd": "rbdmap unmap-all", "msg": "[Errno 2] No such file or directory", "rc": 2}
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* Version-Release number of selected component (if applicable):
ceph-ansible-3.2.24

* How reproducible:
Always

* Steps to Reproduce:
1. Make sure you have clients deployed via ceph-anisble and have an entry in /etc/ansible/hosts'
2. Try purging a containerized cluster with 'purge-docker-cluster.yml'

* Actual results:
Purging of the cluster fails.

* Expected results:
The cluster should be purged.

* Additional info:
NA