As I'm moving everything into Kubernetes I needed a way to run debmirror in a Docker container to synchronize my apt repositories.

There wasn't much guidance on how to do this, so here it is.

Some basic background on the image, I used a Debian base image and installed the debmirror and gpg packages. Brought in the correct GPG keys for the repositories I'm mirroring. Finally I set the CMD directive to run debmirror with the correct arguments. Since I wanted to use environment variables for the arguments I used sh -c as the first part which will process the environment variables, without it they are not processed and debmirror is executed with the name of the variable instead of the actual value.

I wanted to use the same image to mirror the Debian, Ubuntu and Docker repositories without building separate images for each one so I included all of the keys in the single image. You could however pull those into separate images, or install through a script, etc, but that's more overhead I didn't want to deal with.

Here is my Dockerfile:

FROM debian:10.5-slim

RUN apt update
RUN apt install -y debmirror gpg

# DEBIAN
RUN gpg -q --keyserver keys.gnupg.net --no-default-keyring --keyring trustedkeys.gpg --recv-keys DC30D7C23CBBABEE 4DFAB270CAA96DFA DCC9EFBF77E11517

# DOCKER
RUN gpg -q --keyserver keys.gnupg.net --no-default-keyring --keyring trustedkeys.gpg --recv-keys 7EA0A9C3F273FCD8

# UBUNTU
RUN gpg -q --keyserver keys.gnupg.net --no-default-keyring --keyring trustedkeys.gpg --recv-keys 871920D1991BC93C

CMD [ "sh", "-c", \
    "debmirror ${DEST} --nosource --host=${HOST} --root=${ROOT} --dist=${DIST} --section=${SECTION} --i18n --arch=${ARCH} --passive --cleanup --method=${METHOD} --progress ${OTHERARGS} --rsync-extra=${RSYNCEXTRA:=trace}" ]

To build it, I used a simple docker command:

docker image build -t debmirror .

A note on which mirror to choose. The mirror that you choose should support rsync. If it doesn't, you'll need to add another environment variable that tells it to ignore the trace files. -e RSYNCEXTRA=none. The standard Debian mirrors do not support rsync and it'll sit at Updating remote trace files (using rsync) ... for a few minutes before finally erroring out. Because of this, for Debian, I chose to use the Oregon State University mirror which is close to me, fast and allows rsync. For Ubuntu I chose to use the Arizona State University mirror. The Docker repository doesn't seem to support rsync so I had to specify the RSYNCEXTRA=none environment variable.

Execution

To run it you can use the following

Debian

Powershell:

docker run --rm -it -e DEST=/mnt/debmirror/debian `
                    -e HOST=debian.oregonstate.edu `
                    -e ROOT=debian/ `
                    -e DIST=buster,buster-updates `
                    -e SECTION=main,contrib,non-free,main/debian-installer `
                    -e ARCH=amd64,arm64,armhf `
                    -e METHOD=http `
                    debmirror

Bash:

docker run --rm -it -e DEST=/mnt/debmirror/debian \
                    -e HOST=debian.oregonstate.edu \
                    -e ROOT=debian/ \
                    -e DIST=buster,buster-updates \
                    -e SECTION=main,contrib,non-free,main/debian-installer \
                    -e ARCH=amd64,arm64,armhf \
                    -e METHOD=http \
                    debmirror

Docker

PowerShell:

docker run --rm -it -e DEST=/mnt/debmirror/docker/debian `
                    -e HOST=download.docker.com `
                    -e ROOT=/linux/debian `
                    -e DIST=buster `
                    -e SECTION=stable `
                    -e ARCH=amd64,arm64,armhf `
                    -e METHOD=https `
                    -e RSYNCEXTRA=none `
                    debmirror

Bash:

docker run --rm -it -e DEST=/mnt/debmirror/docker/debian \
                    -e HOST=download.docker.com \
                    -e ROOT=/linux/debian \
                    -e DIST=buster \
                    -e SECTION=stable \
                    -e ARCH=amd64,arm64,armhf \
                    -e METHOD=https \
                    -e RSYNCEXTRA=none \
                    debmirror

Ubuntu

Powershell:

docker run --rm -it -e DEST=/mnt/debmirror/ubuntu `
                    -e HOST=mirror.arizona.edu `
                    -e ROOT=ubuntu/ `
                    -e DIST=groovy `
                    -e SECTION=main,restricted,universe,multiverse `
                    -e ARCH=amd64 `
                    -e METHOD=http `
                    debmirror

Bash:

docker run --rm -it -e DEST=/mnt/debmirror/ubuntu \
                    -e HOST=mirror.arizona.edu \
                    -e ROOT=ubuntu/ \
                    -e DIST=groovy \
                    -e SECTION=main,restricted,universe,multiverse \
                    -e ARCH=amd64 \
                    -e METHOD=http \
                    debmirror

Conclusion

Using a single container will now allow me to setup any number of  Kubernetes jobs that will sync any apt repository with ease. I just need to update the image with the correct GPG keys.

If I need to mirror too many more of them I will probably put the installation of the GPG keys and execution of debmirror into a script which would then become the executed command. That would allow me to pass in the key id's as an environment variable instead of installing them in the image itself. I just didn't feel the need to add that complexity for this particular purpose. I still may do it as I work on getting this to run in Kubernetes.

I have a post on how to run the site and debmirror all in Kubernetes. It is at https://www.frakkingsweet.com/debian-mirror-in-kubernetes/