Allow mysqlcheck to be enabled/disabled and tuned

The mysqlcheck allows deployers the ability to perform a cluster health
check from anywhere using simple http requests on a specific port. This
change makes it possible for deployers to enable or disable this check
capability. This also allows deployers to change the port used for the
mysqlcheck running within xinetd.

New options:
 + galera_monitoring_check_enabled - bool
 + galera_monitoring_check_port - int

The new options retains the hard-coded values as defaults, it will be
enabled and run on port 9200.

Change-Id: Ic966fbe5dfb39a35ecd10ece2901bb317c905c84
Signed-off-by: Kevin Carter <kevin.carter@rackspace.com>

defaults/main.yml

@@ -81,6 +81,12 @@ galera_monitoring_user_password: ""
 #
 #galera_monitoring_allowed_source: "0.0.0.0/0"
 
+# Enable or disable the galera monitoring check capability
+galera_monitoring_check_enabled: true
+
+# Set the monitoring port used with the galera monitoring check.
+galera_monitoring_check_port: 9200
+
 galera_root_user: root
 
 # WARNING: This option is deprecated and will be removed in v12.0

handlers/main.yml

@@ -93,5 +93,5 @@
 - name: Restart xinetd
   service:
     name: xinetd
-    state: restarted
-    enabled: true
+    state: "{{ (galera_monitoring_check_enabled | bool) | ternary('restarted', 'stopped') }}"
+    enabled: "{{ galera_monitoring_check_enabled | bool }}"

releasenotes/notes/mysqlcheck-options-60fae226d8d4f3ca.yaml

@@ -0,0 +1,8 @@
+---
+features:
+  - It is now possible for deployers to enable or disable the `mysqlcheck`
+    capability. The Boolean option `galera_monitoring_check_enabled` has
+    been added which has a default value of **true**.
+  - It is now possible to change the port used by `mysqlcheck`. The integer
+    option `galera_monitoring_check_port` has been added with the default
+    value of **9200**.

tasks/galera_post_install.yml

@@ -175,33 +175,42 @@
     dest: "/usr/local/bin/galera_new_cluster"
     mode: "0750"
 
-- name: Create clustercheck script
-  template:
-    src: "clustercheck.j2"
-    dest: "/usr/local/bin/clustercheck"
-    mode: "0755"
-
 # TODO: (nicolasbock) This task can be removed in T but is necessary
 # for S and earlier because deployments prior to this change will not
 # have the xinetd service enabled because the handler task runs only
 # for new deployments.
+# NOTE(cloudnull): If `galera_monitoring_check_enabled` is set false
+#                  the xinetd service will be disabled and stopped.
+#                  using the handler.
 - name: Enable xinetd service
   service:
     name: xinetd
-    enabled: yes
-
-- name: Create mysqlchk config
-  template:
-    src: "mysqlchk.j2"
-    dest: "/etc/xinetd.d/mysqlchk"
-    mode: "0644"
+    enabled: "{{ galera_monitoring_check_enabled | bool }}"
   notify:
     - Restart xinetd
 
-- name: Add galera service check to services
-  lineinfile:
-    dest: /etc/services
-    state: present
-    regexp: '^mysqlchk'
-    line: 'mysqlchk    9200/tcp    # MySQL check'
-    backup: yes
+- name: Cluster check block
+  block:
+    - name: Create clustercheck script
+      template:
+        src: "clustercheck.j2"
+        dest: "/usr/local/bin/clustercheck"
+        mode: "0755"
+
+    - name: Create mysqlchk config
+      template:
+        src: "mysqlchk.j2"
+        dest: "/etc/xinetd.d/mysqlchk"
+        mode: "0644"
+      notify:
+        - Restart xinetd
+
+    - name: Add galera service check to services
+      lineinfile:
+        dest: /etc/services
+        state: present
+        regexp: '^mysqlchk'
+        line: 'mysqlchk    9200/tcp    # MySQL check'
+        backup: yes
+  when:
+    - galera_monitoring_check_enabled | bool

templates/mysqlchk.j2

@@ -6,7 +6,7 @@ service mysqlchk
         disable = no
         flags = REUSE
         socket_type = stream
-        port = 9200
+        port = {{ galera_monitoring_check_port }}
         wait = no
         user = nobody
         server = /usr/local/bin/clustercheck