Question

My problem started off with me not being able to log in as root any more on my mysql install. I was attempting to run mysql without passwords turned on… but whenever I ran the command

# mysqld_safe --skip-grant-tables &

I would never get the prompt back. I was trying to follow these instructions to recover the password.

The screen just looks like this:

root@jj-SFF-PC:/usr/bin# mysqld_safe --skip-grant-tables
120816 11:40:53 mysqld_safe Logging to syslog.
120816 11:40:53 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql

and I don’t get a prompt to start typing the SQL commands to reset the password.

When I kill it by pressing CTRL + C, I get the following message:

error: 'Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)'

Check that mysqld is running and that the socket: '/var/run/mysqld/mysqld.sock' exists!

If I retry the command and leave it long enough, I do get the following series of messages:

root@jj-SFF-PC:/run/mysqld# 120816 13:15:02 mysqld_safe Logging to syslog.
120816 13:15:02 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
120816 13:16:42 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended

[1]+  Done                    mysqld_safe --skip-grant-tables
root@jj-SFF-PC:/run/mysqld#

But then if I try to log in as root by doing:

# mysql -u root

I get the following error message:

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

I checked and /var/run/mysqld/mysqld.sock file doesn’t not exist. The folder does, but not the file.

Also, I don’t know if this helps or not, but I ran find / -name mysqld and it came up with:

/var/run/mysqld - folder
/usr/sbin/mysqld - file
/run/mysqld - folder

I don’t know if this is normal or not. But I’m including this info just in case it helps.

I finally decided to uninstall and reinstall mysql.

apt-get remove mysql-server
apt-get remove mysql-client
apt-get remove mysql-common
apt-get remove phpmyadmin

After reinstalling all packages again in the same order as above, during the phpmyadmin install, I got the same error:

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

So I tried again to uninstall/reinstall. This time, after I uninstalled the packages, I also manually renamed all mysql files and directories to mysql.bad in their respective locations.

/var/lib/mysql 
/var/lib/mysql/mysql
/var/log/mysql
/usr/lib/perl5/DBD/mysql
/usr/lib/perl5/auto/DBD/mysql
/usr/lib/mysql
/usr/bin/mysql
/usr/share/mysql
/usr/share/dbconfig-common/internal/mysql
/etc/init.d/mysql
/etc/apparmor.d/abstractions/mysql
/etc/mysql

Then I tried to reinstall mysql-server and mysql-client again. But I’ve noticed that it doesn’t prompt me for a password. Isn’t it supposed to ask for an admin password?

Answer 1

To find all socket files on your system run:

sudo find / -type s

My Mysql server system had the socket open at /var/lib/mysql/mysql.sock

Once you find where the socket is being opened, add or edit the line to your /etc/my.cnf file with the path to the socket file:

socket=/var/lib/mysql/mysql.sock

Sometimes the system startup script that launched the command line executable specifies a flag --socket=path. This flag could override the my.cnf location, and that would result in a socket not being found where the my.cnf file indicates it should be. Then when you try to run the mysql command line client, it will read my.cnf to find the socket, but it will not find it since it deviates from where the server created one. So, Unless you care where the socket resides, just changing the my.cnf to match should work.

Then, stop the mysqld process. How you do this will vary by system.

If you’re super user in the linux system, try one of the following if you don’t know the specific method your Mysql setup uses:

• service mysqld stop
• /etc/init.d/mysqld stop
• mysqladmin -u root -p shutdown
• Some systems aren’t setup to have an elegant way to stop mysql (or for some reason mysql doesn’t respond) and you can force terminate mysql with either:
  • One step: pkill -9 mysqld
  • Two step (least preferred):
    • Find the process id of mysql with either pgrep mysql or ps aux | grep mysql | grep -v grep
    • Assuming the process id is 4969 terminate with kill -9 4969

After you do this you might want to look for a pid file in /var/run/mysqld/ and delete it

Make sure the permissions on your socket is such that whatever user mysqld is running as can read/write to it. An easy test is to open it up to full read/write and see if it still works:

chmod 777 /var/run/mysqld/mysqld.sock

If that fixes the issue, you can tailor the permissions and ownership of the socket as needed based on your security settings.

Also, the directory the socket resides in has to be reachable by the user running the mysqld process.