Monit a pour fonction de “surveiller” service et/ou les ressources système et d’exécuter une ou plusieurs actions en fonction de condition. Par exemple, il peut redémarrer Nginx si celui ci ne répond plus.

Configuration de base épuré

set daemon  60
set logfile syslog facility log_daemon

# Interface web de monit
#set httpd port 2812 and
#     allow login:motdepasse

include /etc/monit/conf.d/*

Configuration des services

Dans /etc/monit/conf.d/, j’y ai placé un fichier de configuration par service :

apache2

check process apache with pidfile /var/run/apache2.pid
  start program = "/etc/init.d/apache2 start"
  stop program  = "/etc/init.d/apache2 stop"
  if children > 149 then restart
  if totalmem > 4096 MB for 5 cycles then restart
  if 3 restarts within 5 cycles then timeout

clamd

check process clamd with pidfile /var/run/clamav/clamd.pid
  group clamav
  start program = "/etc/init.d/clamav-daemon start"
  stop  program = "/etc/init.d/clamav-daemon stop"
  if failed unixsocket /var/run/clamav/clamd.ctl then restart
  if 5 restarts within 5 cycles then timeout

dovecot

check process dovecot with pidfile /var/run/dovecot/master.pid
  group dovecot
  start program = "/etc/init.d/dovecot start"
  stop  program = "/etc/init.d/dovecot stop"
  if failed host 127.0.0.1 port 143 protocol imap then restart
  if failed host 127.0.0.1 port 993 type tcpssl sslauto protocol imap then restart
  if 5 restarts within 5 cycles then timeout

freshclam

check process freshclam with pidfile /var/run/clamav/freshclam.pid
  group clamav
  start program = "/etc/init.d/clamav-freshclam start"
  stop  program = "/etc/init.d/clamav-freshclam stop"
  if 5 restarts within 5 cycles then timeout

mysql

check process mysql with pidfile /var/lib/mysql/mysql.pid
  group mysql
  start program = "/etc/init.d/mysql start"
  stop program = "/etc/init.d/mysql stop"
  if failed host localhost port 3306 then restart
  if 5 restarts within 5 cycles then timeout

named

check process named with pidfile /var/run/named/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

postfix

check process postfix with pidfile /var/spool/postfix/pid/master.pid
  group mail
  start program = "/etc/init.d/postfix start"
  stop  program = "/etc/init.d/postfix stop"
  if failed host localhost port 25 protocol smtp then restart
  if 5 restarts within 5 cycles then timeout

sshd

check process sshd with pidfile /var/run/sshd.pid
  start program  "/etc/init.d/ssh start"
  stop program   "/etc/init.d/ssh stop"
  if failed port 22 protocol ssh then restart
  if 5 restarts within 5 cycles then timeout

Mise en place de Monit