Ask HN: Simple on-premesis uptime monitor?

Is there a simple tool I can install to monitor a few basic services: http, https and ssh?

I've bookmarked like 100 of these things over the years but most are hideously complicated for my current needs. I'm looking for a simple web gui and maybe one cron job here. Know of anything?

(I use pingdom for the 'outside the firewall' view, but that is way more complex than what I need)