collectd

A daemon that collects system performance statistics periodically, and provides tons of plugins to store and analyze these values

     

linux windows osx open-source monitoring c

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

Monit

An open source utility for managing and monitoring processes, programs, files, directories and filesystems

     

linux osx open-source monitoring process-mgmt c

Statman

Statman makes it possible to instrument and collect statistics from your high-traffic production Erlang systems with very low overhead. The collected data points are aggregated in the VM and can be sent to services like Graphite, Munin, New Relic, etc.

     

linux windows osx open-source monitoring erlang

testssl.sh

A command-line tool which checks a server's service on any port for the support of TLS/SSL ciphers, protocols as well as some cryptographic flaws. It's designed to provide clear output for your "is this good or bad" decision.

     

linux osx open-source security shell

Zabbix

An open source, enterprise-class monitoring framework

     

linux windows osx open-source monitoring c