This problem occurs when mysql doesn’t work in the mysql.pid file
on CentOS 7 with LVM storage under LXC,
User access rights and permissions are not defined in the mysql.pid file.
when giving access to chown and chmod it can’t be solved the server responds to “permission denied mysql.pid”
finally found a solution, because the host under LXC Proxmox, I suspect the mysql.pid file is corrupt.
I did “fsck” on centos and the result is blank there is no feedback when I run fsck.
because centos runs under LXC then I do fsck in proxmox by pointing it based on the Centos ID.
and then, I am successful, mysql.pid is running normally.