cephadm_adopt: fetch and write ceph minimal config

This commit makes the playbook fetch the minimal current ceph
configuration and write it later on monitoring nodes so `cephadm` can
proceed with the adoption.
When a monitoring stack was deployed on a dedicated node, it means no
`ceph.conf` file was written, `cephadm` requires a `ceph.conf` in order
to adopt the daemon present on the node.

Closes: https://bugzilla.redhat.com/show_bug.cgi?id=1939887

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>
(cherry picked from commit b445df0479)

infrastructure-playbooks/rolling_update.yml

@@ -118,6 +118,8 @@
   serial: 1
   become: True
   tasks:
+    - name: upgrade ceph mon cluster
+      block:
         - name: remove ceph aliases
           file:
             path: /etc/profile.d/ceph-aliases.sh
@@ -256,6 +258,22 @@
           delay: "{{ health_mon_check_delay }}"
           when: containerized_deployment | bool
 
+      rescue:
+        - name: unmask the mon service
+          systemd:
+            name: ceph-mon@{{ item }}
+            enabled: yes
+            masked: no
+          with_items:
+            - "{{ ansible_facts['hostname'] }}"
+            - "{{ ansible_facts['fqdn'] }}"
+
+        - name: unmask the mgr service
+          systemd:
+            name: ceph-mgr@{{ ansible_facts['hostname'] }}
+            masked: no
+          when: inventory_hostname in groups[mgr_group_name] | default([])
+                or groups[mgr_group_name] | default([]) | length == 0
 
 - name: reset mon_host
   hosts: "{{ mon_group_name|default('mons') }}"