Q. How do I monitor my BIND 9 (named) server with monit which is chrooted at /var/lib/named directory? How do I restart bind (named) server if it does not respond or dead due to any issues under Debian / Ubuntu Linux?

A. You can easily restart or send alert when bind9 is not responding under Debian / Ubuntu or UNIX like operating system using monit.

Restart named (bind9) if does not respond to port 53

Open monitrc file, enter:
# vi /etc/monit/monitrc
Append following code, enter:

## bind
check process named with pidfile /var/lib/named/var/run/bind/run/named.pid
 start program = "/etc/init.d/bind9 start"
 stop program = "/etc/init.d/bind9 stop"
 if failed host 127.0.0.1 port 53 type tcp protocol dns then restart
 if failed host 127.0.0.1 port 53 type udp protocol dns then restart
 if 5 restarts within 5 cycles then timeout

A note about RHEL / CentOS / Red Hat / Fedora Linux

You need following code for RHEL, enter:

## bind
check process named with pidfile /var/named/chroot/var/run/named/named.pid
 start program = "/etc/init.d/named start"
 stop program = "/etc/init.d/named stop"
 if failed host 127.0.0.1 port 53 type tcp protocol dns then restart
 if failed host 127.0.0.1 port 53 type udp protocol dns then restart
 if 5 restarts within 5 cycles then timeout

Save and close the file. Restart monit, enter:
# /etc/init.d/monit restart