package mysql-server-5.7 5.7.17-0ubuntu0.16.04.2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[Marek]

insserv: warning: current start runlevel(s) (empty) of script `mysql' overrides LSB defaults (2 3 4 5).
insserv: warning: current stop runlevel(s) (0 1 2 3 4 5 6) of script `mysql' overrides LSB defaults (0 1 6).
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.
mysql_upgrade failed with exit status 11
dpkg: Fehler beim Bearbeiten des Paketes mysql-server-5.7 (--configure):
 Unterprozess installiertes post-installation-Skript gab den Fehlerwert 1 zurück
dpkg: Abhängigkeitsprobleme verhindern Konfiguration von mysql-server:
 mysql-server hängt ab von mysql-server-5.7; aber:
  Paket mysql-server-5.7 ist noch nicht konfiguriert.

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: mysql-server-5.7 5.7.17-0ubuntu0.16.04.2
Uname: Linux 4.8.3-040803-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_drm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2.5
Architecture: amd64
Date: Sat Apr 8 12:35:27 2017
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2016-04-11 (361 days ago)
InstallationMedia: Ubuntu-GNOME 15.10 "Wily Werewolf" - Release amd64 (20151021)
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: ['performance_schema', 'checkpointdigitalsolutions', 'debian-5.6.flag', 'wordpress_user', 'ks_krappi', 'shopware_demodaten', 'ib_buffer_pool', 'contaotest', 'ib_logfile0', 'mysql', 'holmvintage', 'phpmyadmin', 'contao_rocksolid_luxe', 'debian-5.7.flag', 'wordpress_de', 'auto.cnf', 'ibdata1', 'contao_4_test', 'ib_logfile1', 'iskra_berlin', 'mytrauringstore', 'eee_ltd', 'sys', 'mysql_upgrade_info']
ProcCmdline: BOOT_IMAGE=/vmlinuz-4.8.3-040803-generic root=/dev/mapper/ubuntu--gnome--vg-root ro acpi_os_name=Linux acpi_osi= acpi_backlight=vendor
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.1
 apt 1.2.19
SourcePackage: mysql-5.7
Title: package mysql-server-5.7 5.7.17-0ubuntu0.16.04.2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)
modified.conffile..etc.init.mysql.conf: [modified]
mtime.conffile..etc.init.mysql.conf: 2016-11-18T14:00:06.943578
upstart.mysql.override: manual

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #1680747, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.