Netdata is an open-source monitoring tool that has functionality for monitoring Docker containers' health and performance. With the Docker container integration enabled via cgroups, you get real-time, interactive charts showing key CPU, memory, disk I/O, and networking of entire containers. You can use other collectors to monitor the specific applications or services running inside Docker containers also.

With these per-second metrics, you can receive instant notifications about outages, performance hiccups, or excessive resource usage, visually identify the anomaly, and fix the root cause faster.

Netdata uses control groups—most often referred to as cgroups—to monitor Docker containers. cgroups is a Linux kernel feature that limits and tracks the resource usage of a collection of processes. When you combine resource limits with process isolation (thanks, namespaces!), you get what we commonly refer to as containers.

Linux uses virtual files, usually placed at /sys/fs/cgroup/, to report the existing containers and their resource usage. Netdata scans these files/directories every few seconds (configurable via check for new cgroups every in netdata.conf) to find added or removed cgroups.

Monitoring Docker containers with Netdata is zero-configuration. If you have Docker containers running when you install Netdata, it’ll auto-detect them and start monitoring their metrics. If you spin up Docker containers after installing Netdata, restart it with sudo service netdata restart or the appropriate variant for your system, and you’ll be up and running. Check out the blog post for more info.