Do IPv6 check for supported version.

config.yaml

@@ -47,4 +47,3 @@ options:
     default: false
     type: boolean
     description: "Enable IPv6."
-

hooks/mysql.py

@@ -184,6 +184,7 @@ def configure_db(hostname,
                  username,
                  admin=False):
     ''' Configure access to database for username from hostname '''
+
     if config_get('prefer-ipv6'):
         remote_ip = hostname
     elif hostname != unit_get('private-address'):

hooks/percona_hooks.py

@@ -46,6 +46,7 @@ from percona_utils import (
     seeded, mark_seeded,
     configure_mysql_root_password,
     relation_clear,
+    setup_ipv6
 )
 from mysql import (
     get_mysql_password,
@@ -64,7 +65,7 @@ from charmhelpers.contrib.network.ip import (
     is_address_in_network,
     get_address_in_network,
     get_netmask_for_address,
-    get_ipv6_addr,
+    get_ipv6_addr
 )
 
 hooks = Hooks()
@@ -83,6 +84,9 @@ def install():
     apt_update(fatal=True)
     apt_install(PACKAGES, fatal=True)
     configure_sstuser(config('sst-password'))
+    
+    if config('prefer-ipv6'):
+        setup_ipv6()
 
 
 def render_config(clustered=False, hosts=[]):
@@ -110,6 +114,9 @@ def render_config(clustered=False, hosts=[]):
 @hooks.hook('upgrade-charm')
 @hooks.hook('config-changed')
 def config_changed():
+    if config('prefer-ipv6'):
+        setup_ipv6()
+
     hosts = get_cluster_hosts()
     clustered = len(hosts) > 1
     pre_hash = file_hash(MY_CNF)

hooks/percona_utils.py

@@ -4,7 +4,7 @@ from subprocess import Popen, PIPE
 import socket
 import os
 from charmhelpers.core.host import (
-    lsb_release,
+    lsb_release
 )
 from charmhelpers.core.hookenv import (
     unit_get,
@@ -13,17 +13,18 @@ from charmhelpers.core.hookenv import (
     relation_get,
     relation_set,
     local_unit,
-    config,
+    config
 )
 from charmhelpers.fetch import (
     apt_install,
-    filter_installed_packages,
+    filter_installed_packages
 )
 from charmhelpers.contrib.network.ip import (
-    get_ipv6_addr,
+    get_ipv6_addr
 )
 from mysql import get_mysql_root_password, MySQLHelper
 
+
 try:
     import jinja2
 except ImportError:
@@ -106,6 +107,7 @@ def get_cluster_hosts():
     for relid in relation_ids('cluster'):
         for unit in related_units(relid):
             private_address = relation_get('private-address', unit, relid)
+
             if config('prefer-ipv6'):
                 hostname = relation_get('hostname', unit, relid)
                 if not hostname or hostname in hosts:
@@ -175,3 +177,9 @@ def render_hosts(map):
         for line in lines:
             hosts.write(line)
 
+
+def setup_ipv6():
+    ubuntu_rel = float(lsb_release()['DISTRIB_RELEASE'])
+    if ubuntu_rel < 14.04:
+        raise Exception("IPv6 is not supported for Ubuntu "
+                        "versions less than Trusty 14.04")