Allow external restart handler orchestration

Allow the playbook to define its own restart handlers in lieu of the
restart tasks included with the role. This is ideal when upstream
load balancer orchestration should occur around service restarts.

Change-Id: Ia0a37527a73c940d4f164e147ce66c40a670c370

defaults/main.yml

@@ -168,3 +168,6 @@ galera_ssl_address: "{{ ansible_host }}"
 # Setting the following variable to 'yes' will disable the PrivateDevices
 # setting in the systemd unit file for MariaDB on CentOS 7 hosts.
 galera_disable_privatedevices: no
+
+# Allow the playbook to orchestrate service restart handlers
+galera_external_restart_handlers: no

handlers/main.yml

@@ -29,6 +29,7 @@
   when:
      - not galera_running_and_bootstrapped | bool
      - ansible_pkg_mgr != "zypper"
+     - not galera_external_restart_handlers | bool
   register: galera_restart
   until: galera_restart | success
   retries: 3
@@ -70,6 +71,7 @@
     - not galera_running_and_bootstrapped | bool
     - not galera_existing_cluster | bool and inventory_hostname == galera_server_bootstrap_node
     - ansible_pkg_mgr == "zypper"
+    - not galera_external_restart_handlers | bool
 
 - name: "Ensure node is not in bootstrap mode"
   lineinfile:
@@ -81,6 +83,7 @@
     - not galera_running_and_bootstrapped | bool
     - (not galera_existing_cluster | bool) or (not inventory_hostname == galera_server_bootstrap_node)
     - ansible_pkg_mgr == "zypper"
+    - not galera_external_restart_handlers | bool
 
 - name: Restart mysql on SUSE
   service:
@@ -89,6 +92,7 @@
   when:
     - not galera_running_and_bootstrapped | bool
     - ansible_pkg_mgr == "zypper"
+    - not galera_external_restart_handlers | bool
   register: galera_restart
   until: galera_restart | success
   retries: 3