Rancher is kubernetes application. It needs to run on top of kubernetes cluster. If you do our “HA” install using helm, it’ll use the cluster that you are deploying it into. If you launch rancher via
docker run, the container spins up a k3s server process to act as the kubernetes cluster.
That’s what that process is and it can be busy because it is doing all the kubernetes things, like reading from and writing to the DB for any api calls that rancher needs to make (which can be a lot if you have a lot of clusters/nodes/other resources being managed by Rancher).