Cabot
Self-hosted, easily-deployable monitoring and alerts service
..."Stage Redis server", "Production ElasticSearch cluster") and send telephone, sms or hipchat/email alerts to your on-duty team if those services start misbehaving or go down - all without writing a line of code. Best of all, you can use data that you're already pushing to Graphite/statsd to generate alerts, rather than implementing and maintaining a whole new system of data collectors. We built Cabot as a Christmas project at Arachnys because we couldn't wrap our heads around Nagios, and nothing else out there seemed to fit our use case. We're open-sourcing it in the hope that others find it useful.