Monit

manual install:

wget https://mmonit.com/monit/dist/binary/5.25.2/monit-5.25.2-linux-arm.tar.gz

tar zxvf monit-5.25.2-linux-arm.tar.gz

cd monit-5.25.2/

sudo cp bin/monit /usr/local/bin/

cp conf/monitrc /etc/

then the monitrc file is in /etc/ not /ect/monit

if installed with apt systemd file is already in.

sudo nano /etc/monit/monitrc

changed:

set alert ractive74@gmail.com

set mailserver smtp.gmail.com port 587 
   username "MYUSER" password "MYPASSWORD"
   using tlsv12

  check system $HOST
    if loadavg (1min) > 4 then alert
    if loadavg (5min) > 2 then alert
    if cpu usage > 95% for 10 cycles then alert
    if memory usage > 75% then alert
    if swap usage > 25% then alert

 check network public with interface eth0
   if failed link then alert

sudo systemctl restart monit

sudo monit -t

sudo monit start all

sudo monit status

monit not starting up correctly on reboot...so I deleted the init.d/monit script and made a monit.service file

# This file is systemd template for monit service. To
# register monit with systemd, place the monit.service file
# to the /lib/systemd/system/ directory and then start it
# using systemctl (see bellow).
#
# Enable monit to start on boot:
#         systemctl enable monit.service
#
# Start monit immediately:
#         systemctl start monit.service
#
# Stop monit:
#         systemctl stop monit.service
#
# Status:
#         systemctl status monit.service

[Unit]
Description=Pro-active monitoring utility for unix systems
After=network.target

[Service]
Type=simple
KillMode=process
ExecStart=/usr/bin/monit -c /etc/monit/monitrc -I
ExecStop=/usr/bin/monit quit
ExecReload=/usr/bin/monit reload
Restart = on-abnormal

[Install]
WantedBy=multi-user.target