Ask HN: What do you use to monitor your infrastructure and system health?

http://www.shinken-monitoring.org This is a fork of Nagios which is distributed.

https://schezzle.com, which coincidentally is a side-project of mine. There are lots of other ones out there too though. During my day job we use things like splunk, cloudwatch, etc.

Solarwinds Orion Server & Application Monitor, Splunk, Lots of custom stuff using python/selenium/phantomjs to go through end user flows, etc...