[vorpalhex]

You need to host across several nodes in different geographic locations and data centers to resist network splits. Then you need some way to slowly roll out upgrades to your monitoring platform over time.

[djsumdog]

I'm just talking about my personal infrastructure. If I host my crap in Vultr or Linode, I should be able to buy one cheap node on another provider just to run a simple status app: something with celary or sidekiq jobs to check my other stuff and intervals and generate a page with some red/yellow/green dots.

[vorpalhex]

How do you know if the monitoring node goes down at the same time as the other servers?

Remember that Linode/Vultr/etc don't run their own datacenters, they share datacenters and sometimes downtime events can exist outside of datacenters.