Decide if we retire flannel and etcd from base image because they require Docker

[pothos]

Current situation

The not well known and therefore not much used systemd services for flannel and etcd require Docker and have many hacks for that to work. However, we want to eventually move Docker out of the base image and anyway expect people to disable Docker nowadays and rather directly use containerd (e.g., through K8s or nerdctl).

Impact

The units are not well maintained and it's actually better if users define them themselves (as was done in Lokomotive).

Ideal future situation

Either both flannel and etcd units are gone from the base image, or, better only flannel is gone and stays etcd around but doesn't use Docker (e.g., it would directly use containerd).

Implementation options

Additional information

[till]

Isn't etcd potentially used for locksmith? To coordinate restarts?

(Unrelated, but is there a ticket to subscribe to for the changes for docker? We are heavy users.)

[pothos]

For now the plan is to continue to ship Docker as part of the base image, don't worry, and even if it's an extension outside of the base image, it would still be enabled by default for compatibility reasons like your use case.

Right, etcd is used for locksmith and I think it's nice to make it easy to use by continuing to include the etcd service, but maybe use containerd directly or the ctr + nspawn approach used in toolbox.
Even nicer would be to provide airlock as simpler alternative by teaching locksmith the fleetlock protocol.

[till]

Thanks 🙏 @pothos