Failed to start MySQL Community Server. (start-limit-hit)
I got after running
sudo mysqld --initialize


  [ERROR] --initialize specified but the data directory has files in it. Aborting.


for me there was a single file in /var/lib/mysql/ that you could just remove

then I got further, but another error stopped me about apparmor where I followed this, which got me further still but am still stuck:

>


  Resolution
  Add permissions for the objects reported in the lines that start with 'name=' in the output to the file /etc/apparmor.d/usr.sbin.mysqld.
  
  In this example, it is required to add r permissions to /proc/*/status and /sys/devices/system/node/. The paths may be different depending on the error messages.
  
  Connect the server via SSH.
  Open the file /etc/apparmor.d/usr.sbin.mysqld in a text editor (for example, vi editor) and add the lines below at the end of the /usr/sbin/mysqld section at the end of the file:


/usr/sbin/mysqld {
...
/proc/*/status r,
/sys/devices/system/node/ r,
/sys/devices/system/node/node*/meminfo r,
/sys/devices/system/node/*/* r,
/sys/devices/system/node/* r,
...
}



  Reload AppArmor configuration for MySQL service:
  
  apparmor_parser -r /etc/apparmor.d/usr.sbin.mysqld
  
  Start MySQL server:
  
  service mysql start
  
  Note: In case MySQL fails to start again, check the output of journalctl -xe for new error messages.