Ubuntu 20.04 can't start mysql server

Question

I did release-upgrade and after this upgrade I have problems with my mysql server. My server looks on place and it is running, but actually is not:

systemctl status mysql.service

● mysql.service - MySQL Community Server
     Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)
     Active: activating (start) since Wed 2020-07-01 14:01:37 EEST; 377ms ago
     Process: 4546 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=0/SUCCESS)
    Main PID: 4554 (mysqld)
    Status: "Server startup in progress"
    Tasks: 1 (limit: 6840)
    Memory: 125.5M
    CGroup: /system.slice/mysql.service
         └─4554 /usr/sbin/mysqld

Jul 01 14:01:37 microserver systemd[1]: Starting MySQL Community Server...

After running following command:

netstat -an|grep LIST|grep 3306 

nothing listen here.

cat /etc/mysql/my.cnf 
[mysqld]

* Basic Settings

user            = mysql
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
port            = 3306
basedir         = /usr
datadir         = /var/lib/mysql
tmpdir          = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking

When I try to start mysql server I have this error:

root@microserver:~# service mysql start
Job for mysql.service failed because the control process exited with error code.
See "systemctl status mysql.service" and "journalctl -xe" for details.

ps ax|grep mysql
9716 ?        Ssl    0:01 /usr/sbin/mysqld
9744 pts/0    S+     0:00 grep --color=auto mysql

When I try to connect:

ps ax|grep mysql
9716 ?        Ssl    0:01 /usr/sbin/mysqld
9744 pts/0    S+     0:00 grep --color=auto mysql

I did pure uninstallation and clearing everything and install again and still can't run the service.

Solution

Why not try to find out why it is not running, check those logs as the error states:

sudo systemctl status mysql.service
sudo journalctl -xe

Comments

[Admin]

looks like AppArmor might be blocking the startup. I got a similar error when I checked sudo journalctl -xe got AVC apparmor="DENIED" operation="mknod" profile="/usr/sbin/mysqld" name="/run/mysqld/mysqlx.sock.lock" pid=XXXX comm="mysqld"...

[Brunis]

Those are as useful as Microsoft error codes

[Admin]

I had a similar issue, found out by running journalctl -xe that AppArmor was blocking the process from starting