Basic monit config to monitor CPU, memory and disk usage

gistfile1.txt

set daemon 30 with start delay 60
set logfile syslog facility log_daemon
set httpd port 2812
    allow localhost

set mailserver localhost
set alert alert@example.com but not on { instance }

mail-format {
    From: noreply@example.com
    Subject: [$HOST] $EVENT $SERVICE
    Message: $DESCRIPTION
             $DATE
}

check system host.example.com
    if loadavg (5min) > 3 for 4 cycles then alert
    if loadavg (15min) > 1 for 4 cycles then alert
    if memory usage > 80% for 4 cycles then alert
    if swap usage > 20% for 4 cycles then alert
    if cpu usage (user) > 80% for 4 cycles then alert
    if cpu usage (system) > 20% for 4 cycles then alert
    if cpu usage (wait) > 20% for 4 cycles then alert

check filesystem "root" with path /dev/sda1
    if space usage > 80% for 8 cycles then alert