package mysql-server-5.7 5.7.22-0ubuntu0.16.04.1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[Patrick Duthilleul]

none

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: mysql-server-5.7 5.7.22-0ubuntu0.16.04.1
ProcVersionSignature: Ubuntu 4.4.0-122.146-generic 4.4.117
Uname: Linux 4.4.0-122-generic i686
ApportVersion: 2.20.1-0ubuntu2.16
Architecture: i386
Date: Mon May 7 10:29:30 2018
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2017-03-03 (430 days ago)
InstallationMedia: Ubuntu 14.04.5 LTS "Trusty Tahr" - Release i386 (20160803)
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: ['mysql_upgrade_info', 'mysql', 'ministage', 'lyceevictorhugo', 'ib_logfile1', 'sys', 'debian-5.7.flag', 'mysqld_safe.pid', 'prestashop', 'ib_buffer_pool', 'ib_logfile0', 'performance_schema', 'ape', 'auto.cnf', 'phpmyadmin', 'ader', 'ibdata1']
ProcCmdline: BOOT_IMAGE=/boot/vmlinuz-4.4.0-122-generic root=UUID=c106995c-a9b6-495c-8954-1b92c8dd3b11 ro quiet splash vt.handoff=7
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.4
 apt 1.2.26
SourcePackage: mysql-5.7
Title: package mysql-server-5.7 5.7.22-0ubuntu0.16.04.1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to xenial on 2017-03-03 (429 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Joshua Powers (powersj)]

From terminal log:

mysql_upgrade: Got error: 2002: Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) while connecting to the MySQL server
Upgrade process encountered error and will not continue.

[Joshua Powers (powersj)]

This looks identical to bug 1670629 so I am marking this as a duplicate. If you disagree or have further information please feel free to update this bug. Thanks!