etcd should not fail when adding an already existing member (#6587)

roles/etcd/tasks/join_etcd_member.yml

@@ -2,7 +2,8 @@
 - name: Join Member | Add member to etcd cluster  # noqa 301 305
   shell: "{{ bin_dir }}/etcdctl member add {{ etcd_member_name }} --peer-urls={{ etcd_peer_url }}"
   register: member_add_result
-  until: member_add_result.rc == 0
+  until: member_add_result.rc == 0 or 'Peer URLs already exists' in member_add_result.stderr
+  failed_when: member_add_result.rc != 0 and 'Peer URLs already exists' not in member_add_result.stderr
   retries: "{{ etcd_retries }}"
   delay: "{{ retry_stagger | random + 3 }}"
   environment: