Remove APT cache (for Dockerfile)

remove_apt_cache

apt-get clean autoclean
apt-get autoremove --yes
rm -rf /var/lib/{apt,dpkg,cache,log}/

@valerio-bozzolan

1. If you have an SSH server on your container, remove your SSH server ASAP. It is not needed to enter inside. That is a FAQ.

There are a number of containers that require allow ssh ingress to the container for legitimate reasons - gitea, gitlab, ssh tunnel deployments, etc

I think the better way to word what you're trying to say is:

If you need to access the shell within the container or execute arbitrary commands inside the container and can remote in to the host, it is advised that you run docker exec -it <container-name> <shell command> (example: docker exec -it traefik sh) from the host rather than install an SSH server in the container.

Executing rm -rf /var/lib/{apt,dpkg,cache,log}/ will corrupt the apt environment and cause the following error:

Error: Could not open lock file /var/lib/dpkg/lock-frontend - open (2: No such file or directory)
Error: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), are you root?

Executing rm -rf /var/lib/{apt,dpkg,cache,log}/ will corrupt the apt environment and cause the following error:

Error: Could not open lock file /var/lib/dpkg/lock-frontend - open (2: No such file or directory)
Error: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), are you root?

Well yes, these commands should be the last RUN ditective given in the Dockerfile in order to reduce the size of it.

If you need to use apt from within the container later for any reason you can try rm -rf /var/lib/{apt,dpkg,cache,log}/* instead. This will keep the folders but remove their contents.