package mysql-server-5.7 5.7.21-1ubuntu1 failed to install/upgrade: installed mysql-server-5.7 package post-installation script subprocess returned error exit status 1

[Warren Lavallee]

During system migration, this error crashed the upgrade leaving the system in a unstable state.
Priority One. No further information available -- test more.

ProblemType: Package
DistroRelease: Ubuntu 18.04
Package: mysql-server-5.7 5.7.21-1ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-148.174~14.04.1-generic 4.4.177
Uname: Linux 4.4.0-148-generic x86_64
NonfreeKernelModules: intel_rapl x86_pkg_temp_thermal coretemp
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
Date: Sun May 17 08:17:01 2020
ErrorMessage: installed mysql-server-5.7 package post-installation script subprocess returned error exit status 1
Logs.var.log.daemon.log:

MySQLConf.etc.mysql.conf.d.mysql.cnf: [mysql]
MySQLConf.etc.mysql.conf.d.mysqldump.cnf:
 [mysqldump]
 quick
 quote-names
 max_allowed_packet = 16M
MySQLConf.etc.mysql.mysql.conf.d.mysqld_safe_syslog.cnf:
 [mysqld_safe]
 syslog
MySQLVarLibDirListing: ['ib_logfile0', 'ibtmp1', 'server-cert.pem', 'ib_buffer_pool', 'ib_logfile1', 'private_key.pem', 'server-key.pem', 'ibdata1', 'ykksm', 'public_key.pem', 'mysql', 'ca-key.pem', 'performance_schema', 'client-cert.pem', 'sys', 'client-key.pem', 'debian-5.7.flag', 'auto.cnf', 'ca.pem']
ProcCmdline: root=UUID=4a061a5c-ede7-40fc-82f4-95e84934224c ro quiet splash $vt_handoff
Python3Details: /usr/bin/python3.6, Python 3.6.5, python3-minimal, 3.6.5-3
PythonDetails: /usr/bin/python2.7, Python 2.7.15rc1, python-minimal, 2.7.15~rc1-1
RelatedPackageVersions:
 dpkg 1.19.0.5ubuntu2
 apt 1.6.1
SourcePackage: mysql-5.7
Title: package mysql-server-5.7 5.7.21-1ubuntu1 failed to install/upgrade: installed mysql-server-5.7 package post-installation script subprocess returned error exit status 1
UpgradeStatus: Upgraded to bionic on 2020-05-17 (0 days ago)

[Rafael David Tinoco (rafaeldtinoco)]

Thank you for taking the time to file a bug report.

Per your console log:

Renaming removed key_buffer and myisam-recover options (if present)
Initialization of mysqld failed: 0
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: 30680
ERROR: Database files are locked. Daemon already running?
Warning: Unable to start the server.
Job 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.

It looks that previous database process (the existing/installed one) hasn't shutdown correctly and it is still holding a lock for the database file. Make sure you kill existing previous databases processes and try again re-starting the mysql service.

Since it seems likely to me that this is a local configuration problem,
rather than a bug in Ubuntu, I am marking this bug as 'Incomplete'.

However, if you believe that this is really a bug in Ubuntu, then we would
be grateful if you would provide a more complete description of the problem
with steps to reproduce, explain why you believe this is a bug in Ubuntu
rather than a problem specific to your system, and then change the bug
status back to "New".

For local configuration issues, you can find assistance here:
http://www.ubuntu.com/support/community

[Launchpad Janitor (janitor)]

[Expired for mysql-5.7 (Ubuntu) because there has been no activity for 60 days.]