package mysql-server-8.0 8.0.28-0ubuntu0.20.04.3 failed to install/upgrade: installed mysql-server-8.0 package post-installation script subprocess returned error exit status 1

[Yogeshwari Bahiram]

mysql server is not running, giving error 500

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: mysql-server-8.0 8.0.28-0ubuntu0.20.04.3
ProcVersionSignature: Ubuntu 5.13.0-27.29~20.04.1-generic 5.13.19
Uname: Linux 5.13.0-27-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.21
AptOrdering:
 mysql-client-8.0:amd64: Install
 mysql-server-8.0:amd64: Install
 mysql-server-core-8.0:amd64: Install
 NULL: ConfigurePending
Architecture: amd64
CasperMD5CheckResult: skip
Date: Sun Feb 6 09:22:45 2022
ErrorMessage: installed mysql-server-8.0 package post-installation script subprocess returned error exit status 1
InstallationDate: Installed on 2020-12-24 (408 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
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.my.cnf: Error: [Errno 40] Too many levels of symbolic links: '/etc/mysql/my.cnf'
ProcCmdline: BOOT_IMAGE=/boot/vmlinuz-5.13.0-27-generic root=UUID=84881e5a-0311-400c-a22e-24577efe1f6e ro quiet splash vt.handoff=7
Python3Details: /usr/bin/python3.8, Python 3.8.10, python3-minimal, 3.8.2-0ubuntu2
PythonDetails: /usr/bin/python3.6, Python 3.6.15, python-is-python2, 2.7.17-4
RelatedPackageVersions:
 dpkg 1.19.7ubuntu3
 apt 2.0.6
SourcePackage: mysql-8.0
Title: package mysql-server-8.0 8.0.28-0ubuntu0.20.04.3 failed to install/upgrade: installed mysql-server-8.0 package post-installation script subprocess returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)

[Christian Ehrhardt  (paelzer)]

Hi,
from your logs I see:

A potential config issue seen when apport tried to get files:

MySQLConf.etc.mysql.my.cnf: Error: [Errno 40] Too many levels of symbolic links: '/etc/mysql/my.cnf'

This is what breaks the upgrade in dpkg:
  Error: Unable to shut down server with process id 25907
  dpkg: error processing package mysql-server-8.0 (--configure):

According to the error log that could be due to:
2022-02-06T03:54:44.590819Z 0 [ERROR] [MY-011300] [Server] Plugin mysqlx reported: 'Setup of socket: '/var/run/mysqld/mysqlx.sock' failed, can't create lock file /var/run/mysqld/mysqlx.sock.lock'

This particular case is a known issue and already being worked on in bug 1899248
I'll mark this one here as a duplicate, please consider participating in that other bug when there is an ask for testing or such.