ceph-mon: Don't set monitor directory mode recursively

After rolling updates performed with
`infrastructure-playbooks/rolling_updates.yml`, files located in
`/var/lib/ceph/mon/{{ cluster }}-{{ monitor_name }}` had mode 0755 (including
the keyring), making them world-readable.

This commit separates the task that configured permissions recursively on
`/var/lib/ceph/mon/{{ cluster }}-{{ monitor_name }}` into two separate tasks:

1. Set the ownership and mode of the directory itself;
2. Recursively set ownership in the directory, but don't modify the mode.

Signed-off-by: Benoît Knecht <bknecht@protonmail.ch>
(cherry picked from commit 0d76826bbb)

roles/ceph-mon/tasks/deploy_monitors.yml

@@ -51,13 +51,25 @@
   changed_when: false
   when: containerized_deployment | bool
 
-- name: create (and fix ownership of) monitor directory
+- name: create monitor directory
   file:
     path: /var/lib/ceph/mon/{{ cluster }}-{{ monitor_name }}
     state: directory
-    owner: "{{ ceph_uid if containerized_deployment else 'ceph' }}"
-    group: "{{ ceph_uid if containerized_deployment else 'ceph' }}"
+    owner: "{{ ceph_uid if containerized_deployment | bool else 'ceph' }}"
+    group: "{{ ceph_uid if containerized_deployment | bool else 'ceph' }}"
     mode: "{{ ceph_directories_mode | default('0755') }}"
+
+# We don't do the recursion in the task above to avoid setting `mode` (which
+# defaults to 0755) on files.
+#
+# This is only needed when upgrading from older versions of Ceph that used to
+# run as `root` (https://github.com/ceph/ceph-ansible/issues/1635).
+- name: recursively fix ownership of monitor directory
+  file:
+    path: /var/lib/ceph/mon/{{ cluster }}-{{ monitor_name }}
+    state: directory
+    owner: "{{ ceph_uid if containerized_deployment | bool else 'ceph' }}"
+    group: "{{ ceph_uid if containerized_deployment | bool else 'ceph' }}"
     recurse: true
 
 - name: create custom admin keyring