Setting up mysql-server-5.7 (5.7.25-0ubuntu0.18.04.2) ...
/var/lib/mysql/ibdata1:  3427
ERROR: Database files are locked. Daemon already running?
Warning: Unable to start the server. Please restart MySQL and run mysql_upgrade to ensure the database is ready for use.
/var/lib/mysql/ibdata1:  3427
ERROR: Database files are locked. Daemon already running?
Warning: Unable to start the server.
qJob for mysql.service failed because the control process exited with error code.
See "systemctl status mysql.service" and "journalctl -xe" for details.
invoke-rc.d: initscript mysql, action "start" failed.
● mysql.service - MySQL Community Server
   Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)
   Active: activating (auto-restart) (Result: exit-code) since Fri 2019-02-22 17:01:47 EST; 13ms ago
  Process: 4367 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/run/mysqld/mysqld.pid (code=exited, status=1/FAILURE)
  Process: 4352 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=0/SUCCESS)
 Main PID: 1071 (code=exited, status=0/SUCCESS)
dpkg: error processing package mysql-server-5.7 (--configure):
 installed mysql-server-5.7 package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
 mysql-server-5.7