docker-in-docker: Feature request - Ability to pin containerd version

[glennschmidt]

On apt-based systems, the feature script installs the moby-engine package, which depends on moby-containerd >= 1.7.0, so it will end up just installing the latest version of containerd available in the repo.

This week, containerd 2.3.0 was released, and it broke my dev containers (containerd/containerd#13346). It would be good if there was a variable we could set to specify what version of moby-containerd to install, as a workaround when these types of issues occur.

[Falco20019]

This is what I did to downgrade (on Ubuntu 24.04), just in case someone else also needs it:
sudo apt-get update && sudo apt-get install -y --allow-downgrades moby-containerd=2.2.3-ubuntu24.04u1

You can use apt list --all-versions moby-containerd | grep 2.2.3 to find your variant.

[mafuba]

+1, hitting this on docker-in-docker Feature with moby-containerd 2.3.0-debian12u1 + moby-engine 29.4.2-debian12u1. Root cause is upstream containerd/containerd#13346 (EROFS-differ init failure cascades into dockerd refusing to start). Workaround we ended up with - a postCreateCommand that idempotently downgrades moby-containerd to 2.2.3-debian12u1:

```bash
PINNED="2.2.3-debian12u1"
if [[ "$(dpkg-query -W -f='${Version}' moby-containerd 2>/dev/null)" != "$PINNED" ]]; then
sudo apt-get update -qq
sudo apt-get install -y --allow-downgrades "moby-containerd=$PINNED"
sudo pkill -9 dockerd containerd 2>/dev/null || true
sudo rm -f /run/docker.pid
sudo /usr/local/share/docker-init.sh &
fi
```

Works, but a containerdVersion knob on the Feature would let us drop the workaround once containerd/containerd#13328 ships.

[silva-renan]

+1 facing this issue. Setting "moby": false is also an workaround.