package mysql-server-5.7 5.7.11-0ubuntu6 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[prakash]

This error occurred while upgrading from Ubuntu 14.04 to 16.04

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: mysql-server-5.7 5.7.11-0ubuntu6
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Uname: Linux 4.4.0-21-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
Date: Sun Apr 24 14:39:27 2016
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2015-12-13 (132 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
Logs.var.log.daemon.log:

MySQLConf.etc.mysql.conf.d.mysql.cnf: [mysql]
MySQLConf.etc.mysql.conf.d.mysqld_safe_syslog.cnf:
 [mysqld_safe]
 syslog
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: ['phpmyadmin', 'performance_schema', 'sys', 'learn_unit_zend', 'debian-5.7.flag', 'ibtmp1', 'zf2tutorial', 'report', 'ib_logfile1', 'learn_crud', 'ibdata1', 'ib_buffer_pool', 'auto.cnf', 'ci_doctrine', 'learn_ci', 'ib_logfile0', 'debian-5.5.flag', 'mysql_upgrade_info', 'mysql']
ProcCmdline: BOOT_IMAGE=/boot/vmlinuz-4.4.0-21-generic root=UUID=8e033311-6dbb-4059-9154-67de107806e9 ro quiet splash
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1
 apt 1.2.10ubuntu1
SourcePackage: mysql-5.7
Title: package mysql-server-5.7 5.7.11-0ubuntu6 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to xenial on 2016-04-24 (0 days ago)

[Launchpad Janitor (janitor)]

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