update: skip mds deactivation when no mds in inventory

Let's skip this part of the code if there's no mds node in the
inventory.

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>
(cherry picked from commit 5ec906c3af)

infrastructure-playbooks/rolling_update.yml

@@ -465,10 +465,14 @@
   hosts: "{{ groups[mon_group_name|default('mons')][0] }}"
   become: true
   roles:
-    - ceph-defaults
-    - ceph-facts
+    - role: ceph-defaults
+    - role: ceph-facts
+      when: groups.get(mds_group_name, []) | length > 1
 
   post_tasks:
+    - name: deactivate all mds rank > 0
+      when: groups.get(mds_group_name, []) | length > 1
+      block:
         - name: get mds cluster status
           command: "{{ docker_exec_cmd }} ceph --cluster {{ cluster }} fs get {{ cephfs }} -f json"
           changed_when: false
@@ -511,12 +515,6 @@
             mds_active_name: "{{ (_mds_active_name.stdout | from_json)['info'][item.key]['name'] }}"
           with_dict: "{{ (_mds_active_name.stdout | from_json).info }}"
 
-    - name: create active_mdss group
-      add_host:
-        name: "{{ mds_active_name }}"
-        groups: active_mdss
-        ansible_host: "{{ hostvars[mds_active_name]['ansible_host'] | default(omit) }}"
-        ansible_port: "{{ hostvars[mds_active_name]['ansible_port'] | default(omit) }}"
 
         - name: create standby_mdss group
           add_host:
@@ -553,11 +551,18 @@
           delay: 5
           until: (wait_standbys_down.stdout | from_json).standbys | length == 0
 
+    - name: create active_mdss group
+      add_host:
+        name: "{{ mds_active_name if mds_active_name is defined else groups.get(mds_group_name)[0] }}"
+        groups: active_mdss
+        ansible_host: "{{ hostvars[mds_active_name if mds_active_name is defined else groups.get(mds_group_name)[0]]['ansible_host'] | default(omit) }}"
+        ansible_port: "{{ hostvars[mds_active_name if mds_active_name is defined else groups.get(mds_group_name)[0]]['ansible_port'] | default(omit) }}"
+
 
 - name: upgrade active mds
   vars:
     upgrade_ceph_packages: True
-  hosts: active_mdss
+  hosts: active_mdss | default([])
   become: true
   pre_tasks:
     - name: prevent restart from the packaging