Check that mysqld is running and that the socket: '/tmp/mysql.sock' exists!

[root@datanode01 bin]# /usr/local/mysql/bin/mysqladmin -u root password 'root'
/usr/local/mysql/bin/mysqladmin: connect to server at 'localhost' failed
error: 'Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)'
Check that mysqld is running and that the socket: '/tmp/mysql.sock' exists!
解决：
ln -s /usr/local/mysql/mysql.sock /tmp/mysql.sock