Check if this role is deployed as part of the cluster

This makes it possible to deploy a galara cluster in one set of hosts
and a separate stand alone mariadb on another host.

roles/mariadb/tasks/main.yml

@@ -11,9 +11,9 @@
     state: directory
     mode: 0777
   with_items:
-      - /srv/mariadb/lib/mysql
-      - /srv/mariadb/etc/mysql
-      - /srv/mariadb/etc/mysql/conf.d
+    - /srv/mariadb/lib/mysql
+    - /srv/mariadb/etc/mysql
+    - /srv/mariadb/etc/mysql/conf.d
 
 - name: place settings file
   copy:
@@ -21,12 +21,14 @@
     dest: /srv/mariadb/etc/mysql/conf.d/my.cnf
     mode: 660
 
-- name: Set galara.cnf on node if we have at least three nodes.
+- name: >
+        Set galara.cnf on node if we have at least three nodes.
+        And we're part of the cluster.
   template:
     src: files/galera.cnf
     dest: /srv/mariadb/etc/mysql/conf.d/galera.cnf
     mode: 660
-  when: groups['databases'] | length >= 3
+  when: "'databases' in group_names and groups['databases'] | length >= 3"
 
   # This mimics galera_new_cluster.sh
 - name: Initialize a new cluster.
@@ -47,7 +49,8 @@
         name: mysql.service
         state: started
 
-  when: groups['databases'] | length >= 3 and ansible_hostname == hostname_node0
+  when: "'databases' in group_names and groups['databases'] \
+         | length >= 3 and ansible_hostname == hostname_node0"
 
 - name: install service file.
   block:
@@ -61,12 +64,22 @@
         group: root
 
 - name: Give the master node some time to initialize the cluster.
-  command: bash -c "sleep 60 && systemctl daemon-reload"
+  command: bash -c "sleep 60"
+  when: "'databases' in group_names and groups['databases'] \
+         | length >= 3"
+
+- name: Daemon reload (the implicit doesn't work)
+  command: bash -c "systemctl daemon-reload"
 
 - name: make sure service is started
   systemd:
     name: mysql.service
     state: started
+    daemon_reload: yes
 
 - name: start service at boot.
   command: systemctl reenable mysql.service
+
+- name: Give the cluster some time to initialize replication.
+  command: bash -c "sleep 60 && systemctl daemon-reload"
+  when: "'databases' in group_names and groups['databases'] | length >= 3"