A quick note to clean up Docker overlay2 garbage

This article describes my step to clean up the mysterious disk usage by Docker in a Kubernetes cluster.

It has been a long time since I found some strange disk usage in some of my Kubernetes nodes. Among a few similar nodes, a few of them have used much more disk space than others. After some comparison I found the difference is in folder /var/lib/docker/overlay2

Some search led me to this couple years old post.

After some basic Docker cleanup:

# docker system df
TYPE…