Adds mysql-common element

This element contains code shared by mysql and mariadb elements.

Change-Id: I5edc6c2cebfa36d16cf3dcd110c2fe1488c9c3ab

elements/mysql-common/README.md

@@ -0,0 +1,32 @@
+This element contains code common for mysql and mariadb elements, make sure
+you include once of them when including this element.
+
+TODO: auto-tune settings based on host resources or metadata service.
+
+Configuration
+-------------
+
+Users will be created if Heat Metadata is passed in under the
+'mysql.create-users' section. For example:
+
+    mysql:
+      create-users:
+        - username: dbuser1
+          database: somedb
+          userhandle:
+            Ref: SomeWaitConditionHandle
+
+This will cause mysql to create the user 'dbuser1' if it does not exist,
+and grant it all privileges on somedb. It will have a random password
+generated and passed to the WaitConditionHandle with the key of the
+username, and password as the data. A password can also be given for
+the user like this:
+
+    mysql:
+      create-users:
+        - username: dbuser2
+          database: somedb
+          password: abcdefg12345
+
+If a userhandle is also given with the password, it will be passed to
+the wait condition handle in the same manner.

elements/mysql-common/element-deps

@@ -0,0 +1,4 @@
+iptables
+os-apply-config
+os-refresh-config
+use-ephemeral

elements/mysql/README.md

@@ -1,31 +1,5 @@
-Set up a MySQL server install in the image.
+Installs Percona Xtradb Cluster which is Mysql+HA solution
 
-TODO: auto-tune settings based on host resources or metadata service.
-
-Configuration
--------------
-
-Users will be created if Heat Metadata is passed in under the
-'mysql.create-users' section. For example:
-
-    mysql:
-      create-users:
-        - username: dbuser1
-          database: somedb
-          userhandle:
-            Ref: SomeWaitConditionHandle
-
-This will cause mysql to create the user 'dbuser1' if it does not exist,
-and grant it all privileges on somedb. It will have a random password
-generated and passed to the WaitConditionHandle with the key of the
-username, and password as the data. A password can also be given for
-the user like this:
-
-    mysql:
-      create-users:
-        - username: dbuser2
-          database: somedb
-          password: abcdefg12345
-
-If a userhandle is also given with the password, it will be passed to
-the wait condition handle in the same manner.
+Mysql and mariadb elements are very similar so both depend on mysql-common
+element which contains shared logic. See mysql-common for more details about
+mysql setup.

elements/mysql/element-deps

@@ -1,4 +1 @@
-iptables
-os-apply-config
-os-refresh-config
-use-ephemeral
+mysql-common