in my case, to have a clean MySQL start, had to do this:
sudo nano /etc/apparmor.d/usr.sbin.mysqld # add capability dac_read_search, /sys/devices/system/node/ r, /sys/devices/system/node/node*/meminfo r, /sys/devices/system/node/*/* r, /sys/devices/system/node/* r,
sudo apparmor_parser -r /etc/apparmor.d/usr.sbin.mysqld service mysql restart
in my case, to have a clean MySQL start, had to do this:
sudo nano /etc/apparmor. d/usr.sbin. mysqld devices/ system/ node/ r, devices/ system/ node/node* /meminfo r, devices/ system/ node/*/ * r, devices/ system/ node/* r,
# add
capability dac_read_search,
/sys/
/sys/
/sys/
/sys/
sudo apparmor_parser -r /etc/apparmor. d/usr.sbin. mysqld
service mysql restart