First class support for cAdvisor

[dimroc]

Kamal has lots of perks for vertical scaling: getting one big box and divvying up resources like cpus and memory with docker. It would be great if we could easily monitor each individual docker container on a host to see which role or accessory is hogging metrics.

https://github.com/google/cadvisor already exists to do just this, and is being used by kubelet in kubernetes.

It would be fantastic to if we had some documentation or tooling to easily spin up cAdvisor and its UI endpoint alongside your services in a kamal deploy.yml.

If there is another mechanism for gaining insight into container resource usage, please let me know.