How to resolve mysql.sock error

[CommunityUser]

I came across this and thought others might be interested. 

When you host your own controller, you may have a error during startup/install:

151029 12:51:27 InnoDB: 5.5.45 started; log sequence number 11059118728182

151029 12:51:27 [Note] Server hostname (bind-address): '0.0.0.0'; port: 3389

151029 12:51:27 [Note]   - '0.0.0.0' resolves to '0.0.0.0';

151029 12:51:27 [Note] Server socket created on IP: '0.0.0.0'.

151029 12:51:27 [ERROR] Can't start server : Bind on unix socket: Address already in use

151029 12:51:27 [ERROR] Do you already have another mysqld server running on socket: /tmp/mysql.sock ?

151029 12:51:27 [ERROR] Aborting

151029 12:51:27  InnoDB: Starting shutdown...

151029 12:51:28  InnoDB: Shutdown completed;

By default, the controller assumes you can use /tmp/mysql.sock to start the socket connection to start up the database. If for some reason you have another instance of MySql running on the box, this could also happen. 

I suggest you do the following: 

1. sudo <controller dir>/bin/controller.sh stop-appserver
2. sudo <controller dir>/bin/controller.sh stop-db
3. Edit db.cnf: <controller dir>/db/db.cnf. add 

• socket=<controller dir>/db/mysql.sock under the [mysqld] of db.cnf. This ensures that is starts its own socket and not the defautl MySql socket.

4. Restart the controller and you shoudl be good to go.