Unable to start MySQL service. Another MySQL daemon is already running with the same UNIX socket

Š•verything happens for the first time ever.

Today, first time I have seen such MySQL service error during start: Unable to start MySQL service. Another MySQL daemon is already running with the same UNIX socket.

First item to check: main MySQL service log /var/log/mysqld.log and main configuration file /etc/my.cnf

Then I have found nice KB article on Rackspace: http://kb.parallels.com/en/119334

It has helped me to solve this problem.

I have runned command to kill all possible running MySQL daemons:

# killall -9 mysqld_safe mysqld

And then I have made changes below to MySQL service startup script /etc/init.d/mysqld:

# cp -fv /etc/init.d/mysqld /etc/init.d/mysqld.orig
# diff -c /etc/init.d/mysqld.orig /etc/init.d/mysqld

+       # We check if there is already a process using the socket file,
+       # since otherwise this init script could report false positive
+       # result and mysqld_safe would remove the socket file, which
+       # actually uses a different daemon.
+       if fuser "$socketfile" &>/dev/null ; then
+           echo "Socket file $socketfile exists. Is another MySQL daemon already running with the same unix socket?"
+           action $"Starting $prog: " /bin/false
+           return 1
+       fi

-       if [ -S "$socketfile" ] ; then
-           echo "Another MySQL daemon already running with the same unix socket."
-           action $"Starting $prog: " /bin/false
-           return 1
-       fi

Then I have started MySQL server using command:

# /etc/init.d/mysqld start

There is another method to fix problems with MySQL server error:
Another MySQL daemon already running with the same unix socket

Run command:

# rm -fv $(grep socket /etc/my.cnf | cut -d= -f2) && /sbin/service mysqld start

Both of methods listed above has solved MySQL issues for me.