Consul
Consul makes it simple for services to register themselves and to discover other services via a DNS or HTTP interface. Register external services such as SaaS providers as well
linux windows osx open-source service-discovery go monitoring
FastForward
Flexible operating-system event and metric forwarding agent. Receives input and forwards output using plugins.
linux windows osx open-source metrics monitoring ruby
KairosDB
KairosDB is a fast distributed scalable time series database written on top of Cassandra. RESTful JSON-based query/results. Includes flot-based visualization.
linux windows osx open-source metrics visualization java cassandra
Kibana
Kibana is a modern, beautiful visualization tool that works seamlessly with Logstash and ElasticSearch. It features a no-code setup, realtime analytics, and much more.
linux windows osx open-source monitoring nodejs visualization
Supervisor
Supervisor can manage application processes. It can start and stop a group of processes, restart processes if any of them terminate (keep-alive), start multiple instances of the same process (process pooling), automatically manage PID files, and much more! Very useful if you need to manage multiple processes for your application.
linux osx open-source process-mgmt python