nfs: do not create the nfs user if already present

Check if the user exists and skip its creation if true.

Closes: https://github.com/ceph/ceph-ansible/issues/3254
Signed-off-by: Sébastien Han <seb@redhat.com>

roles/ceph-nfs/tasks/create_rgw_nfs_user.yml

@@ -5,7 +5,17 @@
   when:
     - containerized_deployment
 
-- name: create rgw nfs user
+- name: check if "{{ ceph_nfs_rgw_user }}" exists
+  command: "{{ docker_exec_cmd_nfs | default('') }} radosgw-admin --cluster {{ cluster }} user info --uid={{ ceph_nfs_rgw_user }}"
+  run_once: true
+  register: rgwuser_exists
+  changed_when: false
+  failed_when: false
+  delegate_to: "{{ groups[mon_group_name][0] }}"
+  when:
+    - nfs_obj_gw
+
+- name: create rgw nfs user "{{ ceph_nfs_rgw_user }}"
   command: "{{ docker_exec_cmd_nfs | default('') }} radosgw-admin --cluster {{ cluster }} user create --uid={{ ceph_nfs_rgw_user }} --display-name='RGW NFS User'"
   run_once: true
   register: rgwuser
@@ -13,10 +23,11 @@
   delegate_to: "{{ groups[mon_group_name][0] }}"
   when:
     - nfs_obj_gw
+    - rgwuser_exists.get('rc', 1) != 0
 
 - name: set_fact ceph_nfs_rgw_access_key
   set_fact:
-    ceph_nfs_rgw_access_key: "{{ (rgwuser.stdout | from_json)['keys'][0]['access_key'] }}"
+    ceph_nfs_rgw_access_key: "{{ (rgwuser.stdout | from_json)['keys'][0]['access_key'] if rgwuser_exists.get('rc', 1) != 0 else (rgwuser_exists.stdout | from_json)['keys'][0]['access_key'] }}"
   delegate_to: "{{ groups[mon_group_name][0] }}"
   when:
     - nfs_obj_gw
@@ -24,7 +35,7 @@
 
 - name: set_fact ceph_nfs_rgw_secret_key
   set_fact:
-    ceph_nfs_rgw_secret_key: "{{(rgwuser.stdout | from_json)['keys'][0]['secret_key']}}"
+    ceph_nfs_rgw_secret_key: "{{ (rgwuser.stdout | from_json)['keys'][0]['secret_key'] if rgwuser_exists.get('rc', 1) != 0 else (rgwuser_exists.stdout | from_json)['keys'][0]['secret_key'] }}"
   delegate_to: "{{ groups[mon_group_name][0] }}"
   when:
     - nfs_obj_gw