Установка

apt-get install monit

Мониторинг PostgreSQL

check process postgres with pidfile /var/postgres/postmaster.pid
    group database
    start program = "/etc/init.d/postgresql start"
    stop program = "/etc/init.d/postgresql stop"
    if failed host 127.0.0.1 port 5432 protocol pgsql then restart

Мониторинг nginx

check process nginx with pidfile /var/run/nginx.pid
    start program = "/etc/init.d/nginx start"
    stop program  = "/etc/init.d/nginx stop"
    group www-data (for ubuntu, debian)