When I run apt-get install percona-server-server-5.6, the percona server gets installed and started. The processes running (ps -ef | grep mysql) look like this (HOSTNAME is obfuscated):
root 14309 1 0 23:54 ? 00:00:00 /bin/sh /usr/bin/mysqld_safe --datadir=/var/lib/mysql --pid-file=/var/lib/mysql/HOSTNAME.pid
mysql 14413 14309 3 23:54 ? 00:00:00 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib/mysql/plugin --user=mysql --log-error=/var/lib/mysql/HOSTNAME.err --pid-file=/var/lib/mysql/HOSTNAME.pid
My question is where is this default PID file coming from? There is no my.cnf file under /etc/mysql and the my.cnf file under /usr doesn't have any of this information. This is causing a problem ebcause when I deploy my configuration file and try to restart the server, the box obviously doesn't work. I believe the correct default for the PID file is /var/run/mysqld/mysqld.pid.
Looks like this is being set in the init mysql file.