An idea could be to implement the ssh subcommand to connect to the spawned containers instead of using the "standard" ssh client, like for example how vagrant ssh ... works.

This could then be used to:

• Set the FQDN instead of relying on systemd-resolved split DNS (and maybe remove the systemd-resolved dependency?)
• Avoid extra SSH configuration in user's configuration file
• Always use the correct SSH private key instead of copying it into the user's ssh configuration folder

Let me know if this could be a practical idea