Mysql not running after upgrading mysql version - mysql

Question

Following this link I upgraded my MySQL version from 5.5 to 5.7 on my ubuntu 14.04 droplet. But after upgrading MySQL is unable to start showing this error.
mysqld: Can't read dir of '/etc/mysql/mysql.conf.d/' (Errcode: 13 - Permission denied)
mysqld: [ERROR] Fatal error in defaults handling. Program aborted!
How to resolve this problem?

Answer 1

In my case AppArmor was preventing MySQL from accessing this directory. I disabled it with:
sudo ln -s /etc/apparmor.d/usr.sbin.mysqld /etc/apparmor.d/disable/
sudo apparmor_parser -R /etc/apparmor.d/usr.sbin.mysqld
I found this solution here.
Another approach would be to adjust configuration inside /etc/apparmor.d/usr.sbin.mysqld.

Answer 2

You try to use chmod to set permissions for the folder
chmod 755 /etc/mysql/mysql.conf.d
mysql.conf.d is a new file can be added

Answer 3

Sometimes the reason mysql don't start or work is because your system memory is probably full, so you may need to run "apt autoremove" and sometimes "apt autoclean", to be sure on what is wrong exactly run "service mysql status"

Answer 4

These are the steps to correct this:
Back up your my.cnf file in /etc/mysql and remove or rename it
sudo mv /etc/mysql/my.cnf /etc/mysql/my.cnf.bak
Remove the folder /etc/mysql/mysql.conf.d/ using
sudo rm -r /etc/mysql/mysql.conf.d/
Verify you don't have a my.cnf file stashed somewhere else (I did in my home dir!) or in /etc/alternatives/my.cnf use
sudo find / -name my.cnf
Backup and remove /etc/mysql/debian.cnf files (not sure if needed, but just in case)
sudo mv /etc/mysql/debian.cnf /etc/mysql/debian.cnf.bak
sudo apt purge mysql-server mysql-server-5.7 mysql-server-core-5.7
sudo apt install mysql-server
In case your syslog shows an error like "mysqld: Can't read dir of '/etc/mysql/conf.d/'" create a symbolic link:
sudo ln -s /etc/mysql/mysql.conf.d /etc/mysql/conf.d
Then the service should be able to start with sudo service mysql start.

Answer 5

Some times mysql will not start due to your system memory is probably full or some dependency issues. so you may need to clean your memory before start mysql.
you can try this to resolve your issue
apt-get autoremove
apt-get remove --purge mysql*
apt-get autoclean
deluser mysql
rm -rf /var/log/mysql
rm -rf /var/lib/mysql
rm -rf /etc/mysql
Anyway these are the correct steps to upgrade mysql
Back up your my.cnf file in /etc/mysql and remove or rename it
sudo mv /etc/mysql/my.cnf /etc/mysql/my.cnf.bak
Remove the folder /etc/mysql/mysql.conf.d/ using
sudo rm -r /etc/mysql/mysql.conf.d/
Verify you don't have a my.cnf file stashed somewhere else (I did in my home dir!) or in /etc/alternatives/my.cnf use
sudo find / -name my.cnf
Backup and remove /etc/mysql/debian.cnf files (not sure if needed, but just in case)
sudo mv /etc/mysql/debian.cnf /etc/mysql/debian.cnf.bak
sudo apt purge mysql-server mysql-server-5.7 mysql-server-core-5.7
sudo apt install mysql-server
In case your syslog shows an error like "mysqld: Can't read dir of '/etc/mysql/conf.d/'" create a symbolic link:
sudo ln -s /etc/mysql/mysql.conf.d /etc/mysql/conf.d
Then the service should be able to start with sudo service mysql start