Apparmor error after mysql folder relocation

I followed the following steps to change the default data directory in mysql:

I have the configuration of the system as follows

mysql Ver 14.14 Distrib 5.7.19

Ubuntu 16.04 LTS

The steps are as follows:

1. Stop the mysql server service mysql stop

2. Edit the file /etc/mysql/mysql.conf.d/mysqld.cnf and edit the datadir field to point to new location.

   For example datadir = /data/mysql

3. Then copy the content of /var/lib/mysql to new location:

   cp -pr /var/lib/mysql /data
   

4. Then edit the /etc/apparmor.d/usr.sbin.mysqld file. Remove /var/lib/mysql and add the new datadir location. In my case it is

    # Allow data dir access
    /data/mysql/ r,
    /data/mysql/** rwk,
   

5. Restart apparmor service systemctl restart apparmor

6. Restart the mysql service service mysql start

   The above steps worked for me, I hope it will work for you too.

Always check the Apparmor status

1. sudo service apparmor status
2. If it is not active, use journalctl -xe, and verify which profile has problems.