Normalize the server_addr dashboard backend

The server_addr dashboard backend should be the same argument used as
instance of the current ceph-mgr container running on a controller node.
Due to a recent change in pacific the container name and the ceph-mgr
instance are not consistent anymore, and the purpose of this patch is to
rework the way this info is retrieved from ceph.

Closes-Bug: #1972729
Change-Id: Ifc9a0a9ac2f13c891ccde826aef2ab7cbdb5d690

tripleo_ansible/roles/tripleo_cephadm/tasks/dashboard/configure_dashboard_backends.yml

@@ -16,20 +16,20 @@
 
 - name: Get the current mgr
   command: |
-    {{ container_cli }} ps -a -f 'name=ceph-?(.*)-mgr.*' --format \{\{\.Names\}\}
+    {{ container_cli }} ps -a -f 'name=ceph-?(.*)-mgr.*' --format \{\{\.Command\}\} --no-trunc
   register: ceph_mgr
   become: true
   delegate_to: "{{ dashboard_backend }}"
 
 - name: Check the resulting mgr container instance
   debug:
-    msg: "{{ ceph_mgr.stdout | regex_replace('^ceph-?(.*)-mgr.', '') }}"
+    msg: "{{ ceph_mgr.stdout | regex_replace('^-n mgr.(.*)(?P<inst>) -f (.*)+$', '\\1') }}"
   when: tripleo_cephadm_verbose | bool
 
 - name: config the current dashboard backend
   command: |
     {{ tripleo_cephadm_ceph_cli }} config set \
-    mgr mgr/dashboard/{{ ceph_mgr.stdout | regex_replace('^ceph-?(.*)-mgr.', '') }}/server_addr \
+    mgr mgr/dashboard/{{ ceph_mgr.stdout | regex_replace('^-n mgr.(.*)(?P<inst>) -f (.*)+$', '\\1') }}/server_addr \
     {{ hostvars[dashboard_backend][tripleo_ceph_dashboard_net] }}
   become: true
   changed_when: false