Container Advisor (cAdvisor) is a project developed by Google that collects, aggregates, analyzes, and exposes data from running containers. The data available covers pretty much anything you might require, from memory limits to GPU metrics, all available and segregated by container and/or host.

cAdvisor isn't tied to Docker containers but it's usually deployed as one. Data is collected from the container daemon and Linux cgroups, making the discovery of containers transparent and completely automatic. It also exposes process limits and throttling events whenever these limits are reached, which is important information to keep an eye on to maximize infrastructure resource usage without negatively impacting workloads.

Besides exposing metrics in the Prometheus format, cAdvisor also ships with a useful web interface, allowing the instant visualization of the status of hosts and their containers.