MySQL Daemon Lock issue

Solution 1:

Note to future travelers: It depends on your specific configuration but this is very likely an issue with apparmor. If you don't want to disable locking take a look at syslog and see if you're getting apparmor denies on that file.

You'll see something like: apparmor="DENIED" operation="open" parent=29871 profile="/usr/sbin/mysqld" name="/run/mysqld/mysqld.sock.lock"

And can fix it by adding /run/mysqld/mysqld.sock.lock rw to /etc/apparmor.d/usr.sbin.mysqld near the other /run/* entries and reloading apparmor.

Solution 2:

Fixed. Add skip-external-locking to my.cnf under the [mysqld] section, and then reboot the entire system. This should fix it, for anyone who finds this. Also if you backed up your data, then attempted to restore and were told to rm ib* to make it work, you need the ibdata file.