Zabbix - Track, record, alert and visualize performance and availability of IT resources
Ansible - Radically simple configuration-management, application deployment, task-execution, and multi-node orchestration engine
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
Jenkins - Jenkins is an open-source continuous integration server with 300+ plugins to support all kinds of software development
Wireshark - Wireshark is a network protocol analyzer for Unix and Windows. It lets you capture and interactively browse the traffic running on a computer network.
Puppet Enterprise - Get started with Puppet Enterprise, or upgrade or expand.