Bookworm and Podman

I’ve spent the last couple days fiddling with Debian Bookworm RC2 in a VM. No issues to report. It’s shaping up to be a great release.

I’ve been looking for a suitable Docker replacement for a few years because of their repeated license shenanigans. Last year I tried switching to Podman, but ran into into several incompatibilities and minor annoyances.

Podman 4.3 ships with Bookworm and seems to fix all the issues I had before. Rootless containers, multi-stage builds, and all of my muscle-memory docker commands now work as expected. There is even a decent clone of docker-compose named (surprise!) podman-compose.

The only real differences I noticed are:

1. The command is podman instead of docker.
2. Image names must be registry-prefixed. Example: FROM docker.io/bash instead of FROM bash.
3. Searches must be registry-prefixed. Example: podman search docker.io/pablotron.

A couple of quick tests:

• Sinatra web application (rootless)
• Go web application (rootless, scratch, multi-stage build)

Update (2023-05-05): I put together a simple web application named Bookman to put podman-compose through it’s paces. It uses multiple containers, multi-stage builds, boot dependencies, secrets, and volumes.

Here’s a log of the setup process, and here’s a screenshot of the exposed web interface.

Update (2023-05-13): I upgraded several VMs from Bullseye (and one from Stretch!?!) to Bookworm, without any significant issues.

After upgrading to Bookworm, I migrated two VMs from Docker to Podman and installed Podman on a third VM. Useful tip: Rootless Podman does not agree with an NFS-mounted home directory.

One workaround is to create a local (that is, non-NFS), user-owned directory and then symlink ~/.local/share/containers to it, like so:

# create local containers directory for user pabs,
# then symlink ~pabs/.local/share/containers to it.
sudo mkdir -pm 700 /data/containers/pabs && \
  sudo chown pabs:pabs /data/containers/pabs && \
  ln -s /data/containers/pabs ~pabs/.local/share/containers

Alternatively, the Podman man page and Storage Table section of the storage.conf documentation suggest editing the graphroot in ~/.config/containers/storage.conf and pointing at a local directory.