Open-Source monitoring tool: Netdata

Run all your infrastructure in a stack, and have the raw power to do it right.

Netdata is an essential, intuitive tool that provides system administrators with real-time performance and security data for their OS, applications, and network devices. Netdata currently offers free alerts for every iota of its current functionality—whether it's dealing with a storage problem or hard drive crash, protecting against SQL injection attacks, or speeding up response times by monitoring your .NET application’s performance—Netdata already delivers everything you need to manage your network infrastructure safely and effectively at no additional cost.

Netdata is built in a distributed fashion for fault tolerance, lifecycle management, and rapid deployment. It provides the intelligence and visibility you need to manage your infrastructure better. Without bias, Netdata provides the same ability for troubleshooting across every workload, in every infrastructure environment. All data is collected in standard and secure formats and can be accessed from virtually any device with an internet connection. It is fundamentally faster and easier to troubleshoot than other network monitoring tools.

Whether you're a server-side developer or a network engineer, Netdata has something to offer everyone, no matter their level of expertise. That doesn't mean it's the best tool for all situations, but it does pack quite a punch in its simplicity and native aptitude for getting to the root of many issues. And best of all? It's completely free across any platform you care to use it on.