Allow resizing ib_logfiles and default to newer (larger) value for it.

defaults/main.yml

@@ -1,6 +1,7 @@
 # file: mysql/defaults/main.yml
 
 # Basic settings
+mysql_config_file: /etc/mysql/my.cnf
 mysql_port: 3306
 mysql_bind_address: "0.0.0.0"
 mysql_default_root_password: ''
@@ -31,7 +32,13 @@ mysql_innodb_buffer_pool_size: '128M'
 mysql_innodb_flush_log_at_trx_commit: 1
 mysql_innodb_lock_wait_timeout: 50
 mysql_innodb_log_buffer_size: '1M'
-mysql_innodb_log_file_size: '5M'
+
+# Note that changing this for MySQL < 5.6 will be handled by stopping MySQL,
+# moving the log files files away and starting it again.
+mysql_innodb_log_file_size: '48M'
+
+# Polling delay for MySQL after restart for changing mysql_innodb_log_file_size.
+mysql_remove_ib_logfile_startup_delay: 5
 
 # Full-Text Search
 mysql_ft_min_word_len: 4

tasks/configure.yml

@@ -1,11 +1,36 @@
 # file: mysql/tasks/configure.yml
 
+- name: Check if the current innodb_log_file_size is already in use.
+  command: grep 'innodb_log_file_size = {{ mysql_innodb_log_file_size }}' {{ mysql_config_file }}
+  register: innodb_log_file_size_changed
+  changed_when: "innodb_log_file_size_changed.rc != 0"
+  failed_when: "innodb_log_file_size_changed.rc >= 2"
+  always_run: yes
+
+- name: MySQL | Get MySQL version.
+  mysql_variables:
+    variable: version
+  register: mysql_version
+  always_run: yes
+
+- name: MySQL | Ensure innodb_fast_shutdown is not 2 if changing InnoDB log size.
+  mysql_variables:
+    variable: innodb_fast_shutdown
+  register: mysql_current_innodb_fast_shutdown
+  when: innodb_log_file_size_changed.rc == 1 and (mysql_version.msg[0][1] | version_compare('5.6.8', 'lt'))
+  failed_when: mysql_current_innodb_fast_shutdown.msg[0][1] == "2"
+  always_run: yes
+
 - name: MySQL | Update the my.cnf
   template:
     src: etc_mysql_my.cnf.j2
-    dest: /etc/mysql/my.cnf
+    dest: "{{ mysql_config_file }}"
     owner: root
     group: root
     mode: 0644
   notify:
     - restart mysql
+
+- name: MySQL | Remove InnoDB log files if size is changed (pre-MySQL 5.6.8).
+  include: rebuild_ib_logfile.yml
+  when: innodb_log_file_size_changed.rc == 1 and (mysql_version.msg[0][1] | version_compare('5.6.8', 'lt'))

tasks/rebuild_ib_logfile.yml

@@ -0,0 +1,22 @@
+# file: mysql/tasks/rebuild_ib_logfile.yml
+
+- name: MySQL | Stop MySQL server to change InnoDB log file size.
+  service:
+    name: mysql
+    state: stopped
+
+- name: MySQL | Move InnoDB logs if changing to a different log file size.
+  command: mv /var/lib/mysql/{{ item }} /tmp/{{ item }}
+  with_items:
+    - ib_logfile0
+    - ib_logfile1
+
+- name: MySQL | Start MySQL server after changing InnoDB log file size.
+  service:
+    name: mysql
+    state: started
+
+- name: MySQL | Wait for MySQL to finish startup.
+  wait_for:
+    port: "{{ mysql_port}}"
+    delay: "{{ mysql_remove_ib_logfile_startup_delay }}"