Is it safe, and how can I delete mysql.sock before mysqld start?

Question

I have CentOS running on virtual machine on my desktop. When my desktop unexpectedly restarts (blue screen, power failure, restart after updates), virtual machine faces the same problem - unexpected shutdown. When VM starts again, /var/lib/mysql/=mysql.sock file (0 bytes) should be deleted, then mysqld service can be started.

Is there any way to avoid manual deletion of this file? Boot script

Answer 1

The only way to avoid manual deletion is relocate mysql.sock

Add this to /etc/my.cnf

[mysqld]
socket=/tmp/mysql.sock

/tmp would be a good choice since /tmp gets wiped out on each server reboot

Make sure mysqld has chmod permission to write mysql.sock to /tmp

Give it a Try !!!

UPDATE 2014-03-21 11:37 EDT

If you cannot get /tmp/mysql.sock to be made, there is a hack you can try.

Run which mysqld_safe

This will tell you where the mysqld_safe is located. When I run it I get

sh-4.1# which mysqld_safe
/usr/bin/mysqld_safe

Open the file in vi, got lines 612-620. I see this

safe_mysql_unix_port=${mysql_unix_port:-${MYSQL_UNIX_PORT:-/var/lib/mysql/mysql.sock}}
# Make sure that directory for $safe_mysql_unix_port exists
mysql_unix_port_dir=`dirname $safe_mysql_unix_port`
if [ ! -d $mysql_unix_port_dir ]
then
  mkdir $mysql_unix_port_dir
  chown $user $mysql_unix_port_dir
  chmod 755 $mysql_unix_port_dir
fi

You could add this line before it

rm -f /var/lib/mysql/mysql.sock

This might do it for you

CAVEAT : Remember, this is a hack. Should mysql not be able to start for you, I will disavow any knowledge of your actions going forward.