Prevent galera_cluster_name from changing.

On a running galera cluster, we don't want to unintentionally allow a
galera_cluster_name from changing. This will cause a cluster to fail to
start (if the nodes are restarted sequentially) as the cluter name value
has changed.

To ensure we can still change this value, a new
"galera_force_change_cluster_name" variable is added, which can be set
to "True" in order to change the cluster name.

Change-Id: I8bae038bd207a15d5731b9c91b78df851a4c1986
(cherry picked from commit 8a9127efbc)

defaults/main.yml

@@ -24,6 +24,10 @@ galera_upgrade: false
 galera_wsrep_node_name: "{{ inventory_hostname }}"
 galera_cluster_name: openstack_galera_cluster
 
+# This variable will prevent the galera_cluster_name from changing unintentionally on a running cluster.
+# To intentionally change the galera_cluster_name set this variable to True
+galera_force_change_cluster_name: False
+
 # The galera server-id should be set on all cluster nodes to ensure
 #  that replication is handled correctly and the error
 #  "Warning: You should set server-id to a non-0 value if master_host is

library/mysql_status_facts

@@ -24,9 +24,9 @@ DOCUMENTATION = """
 ---
 module: mysql_status_facts
 short_description:
-    - A module for gathering mysql status facts.
+    - A module for gathering mysql status and global variable facts.
 description:
-    - A module for gathering mysql status facts.
+    - A module for gathering mysql status and global variable facts.
 author: Rcbops
 """
 
@@ -44,13 +44,17 @@ class MysqlStatusFacts(object):
     def gather_facts(self):
         """Get information about mysql status."""
         try:
-            output = subprocess.check_output(["mysql", "-e", "show status"],
+            status = subprocess.check_output(["mysql", "-e", "show status"],
                                              stderr=subprocess.STDOUT)
+            global_vars = subprocess.check_output(["mysql", "-e",
+                                                   "show global variables"],
+                                                  stderr=subprocess.STDOUT)
         except subprocess.CalledProcessError as e:
             message = 'Mysql fact collection failed: "%s".' % e.output.strip()
             self.module.fail_json(msg=message)
         else:
-            lines = output.split('\n')
+            lines = status.split('\n')
+            lines += global_vars.split('\n')
             facts = dict(l.split('\t') for l in lines if l)
             self.module.exit_json(
                 changed=self.state_change,

releasenotes/notes/galera-force-cluster-name-change-b4ce1e225daa840c.yaml

@@ -0,0 +1,15 @@
+---
+features:
+  - The ``openstack-ansible-galera_server`` role will now prevent
+    deployers from changing the ``galera_cluster_name`` variable
+    on clusters that already have a value set in a running galera
+    cluster.
+    You can set the new ``galera_force_change_cluster_name``
+    variable to ``True`` to force the ``galera_cluster_name``
+    variable to be changed.
+    We recommend setting this by running the galera-install.yml playbook
+    with ``-e galera_force_change_cluster_name=True``, to avoid
+    changing the ``galera_cluster_name`` variable unintentionally.
+    Use with caution, changing the ``galera_cluster_name`` value
+    can cause your cluster to fail, as the nodes won't join if restarted
+    sequentially.

tasks/galera_cluster_state.yml

@@ -64,6 +64,22 @@
   tags:
     - galera-cluster-state-check
 
+- name: Fail if galera_cluster_name doesnt match file value
+  fail:
+    msg: >
+      "The galera_cluster_name variable does not match what is set in mysql.
+       Check your galera_cluster_name setting in your user_*.yml files in /etc/openstack_deploy
+       and compare to the current value in /etc/mysql/conf.d/cluster.cnf on the host, and
+       the wsrep_cluster_name value set in your running galera cluster.
+       If you are sure you want to change this variable you can force change your
+       galera_cluster_name variable by setting 'galera_force_change_cluster_name: True'"
+  when:
+    - mysql_running.rc == 0
+    - mysql_status['wsrep_cluster_name'] != galera_cluster_name
+    - not galera_force_change_cluster_name | bool
+  tags:
+    - galera-cluster-state-check
+
 - set_fact:
     galera_existing_cluster: true
   when: mysql_running.rc == 0