If the contents of CephExternalMultiConfig and CephExtraKeys are not valid the deployment will fail. Users can read the failure message and determine how to get the format valid but it requires some understanding of how ceph-ansible works. It would be nicer if there was a validation to help the user.


Inspect the contents of CephExtraKeys to ensure we have name, caps, mode, key.
Ensure caps has mgr, mon, osd. Ensure key matches "^[a-zA-Z0-9+/]{38}==$". etc
and give a meaningful error message to help the user understand more exactly
where inside of CephExtraKeys they had the problem.

  CephExtraKeys:
        - name: "client.glance"
          caps:
            mgr: "allow *"
            mon: "profile rbd"
            osd: "profile rbd pool=images"
          key: "AQBRgQ9eAAAAABAAv84zEilJYZPNuJ0Iwn9Ndg=="
          mode: "0600"

Similarly we could validate CephExternalMultiConfig. E.g. if a user doesn't supply
the "cluster" parameter then this loop will fail but the user probably wouldn't
understand why without reading the code.

 https://review.opendev.org/#/c/702143/23/tripleo_ansible/roles/tripleo_ceph_work_dir/tasks/prepare.yml

So we should ensure they have all the paramters like this:

  CephExternalMultiConfig:
    - cluster: 'ceph2'
      fsid: 'af25554b-42f6-4d2b-9b9b-d08a1132d3e8'
      external_cluster_mon_ips: '172.18.0.5,172.18.0.6,172.18.0.7'
      keys:
        - name: "client.openstack"
          caps:
            mgr: "allow *"
            mon: "profile rbd"
            osd: "osd: profile rbd pool=volumes, profile rbd pool=backups, profile rbd pool=vms, profile rbd pool=images"
          key: "AQCwmeRcAAAAABAA6SQU/bGqFjlfLro5KxrB1Q=="
          mode: "0600"
      dashboard_enabled: false
    - cluster: 'ceph3'
      fsid: 'e2cba068-5f14-4b0f-b047-acf375c0004a'
      external_cluster_mon_ips: '172.18.0.8,172.18.0.9,172.18.0.10'
      keys:
        - name: "client.openstack"
          caps:
            mgr: "allow *"
            mon: "profile rbd"
            osd: "osd: profile rbd pool=volumes, profile rbd pool=backups, profile rbd pool=vms, profile rbd pool=images"
          key: "AQCwmeRcAAAAABAA6SQU/bGqFjlfLro5KxrB2Q=="
          mode: "0600"
      dashboard_enabled: false

Loop through it to:

- ensure the fsid is a valid uuid
- ensure the key matches "^[a-zA-Z0-9+/]{38}==$"
- ensure external_cluster_mon_ips is valid
- etc.

Then if they don't match, we say what field failed for what reason.

More indepth descriptions of these lists of maps can be found at
https://review.opendev.org/#/c/707847/