Warning: mysqli::mysqli() [mysqli.mysqli]: (HY000/2002): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2) in /var/www/egmonitor/index.php on line 11
The socket file is not found on the default /tmp folder in ubuntu. Rather, it was placed inside /var/run/mysqld/mysqld.sock
You can get this from /etc/mysql/my.cnf file