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
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FastForward
Flexible operating-system event and metric forwarding agent. Receives input and forwards output using plugins.
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KairosDB
KairosDB is a fast distributed scalable time series database written on top of Cassandra. RESTful JSON-based query/results. Includes flot-based visualization.
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Monit
An open source utility for managing and monitoring processes, programs, files, directories and filesystems
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