Must use systemd at least 208

enabled

1

ping.rb

#!/usr/bin/env ruby
lockfile = File.new("/tmp/monitor.lock","w+")

unless lockfile.flock( File::LOCK_NB | File::LOCK_EX )
	puts "%%%%%%%%%%%%%%%%%%%%%%%%% Only an instance can run at a time!"
	exit! 1
end

Signal.trap "KILL" do puts "Exiting (TERM)"; exit! 0 end
Signal.trap "INT" do puts "Exiting (INT)"; exit! 0 end


def enabled?
	str = File.read File.expand_path('../enabled', __FILE__)
	str.to_i == 1 ? true : false
end

def ping
	pid = Process.pid
	puts ". #{ENV['WATCHDOG_USEC']}"
	system "/usr/bin/systemd-notify MAINPID=#{pid} WATCHDOG=1"
end

puts "################ Starting ping app"

loop do
	if enabled?
		ping
	else
		puts "[#{Process.pid}] Skipping ping"
	end
	sleep 1
end

ping.service

[Unit]
Description=PingMonitor

[Service]
ExecStart=/root/ping.rb
WatchdogSec=5s
Restart=on-failure
NotifyAccess=all
TimeoutStopSec=1s

[Install]
WantedBy=multi-user.target