Set up DNS for libvirt

[ekohl]

This sets up a DNS networking hook that reconfigures systemd-resolved to resolve the domain, if the libvirt network has one set. For that it also needs systemd-resolved to be installed.

Currently a draft to try out changes. If this works, #266 can proceed and in other places we can also avoid ugly hacks.

[ekohl]

I get this error, but when I manually SSH in (as non-root) it doesn't show an error:

Network vagrant-libvirt defined from /dev/fd/63
error: Failed to start network vagrant-libvirt
error: error creating bridge interface virbr1: Operation not permitted

[ekohl]

Connecting to qemu:///system worked so now it can ping quadlet.example.com via proper DNS. Obviously this PR right now is only a proof of concept, but I think it can easily be worked into a real thing.

Question is, where do we integrate this? voxpupuli/setup-vagrant?

[archanaserver]

Connecting to qemu:///system worked so now it can ping quadlet.example.com via proper DNS. Obviously this PR right now is only a proof of concept, but I think it can easily be worked into a real thing.

Question is, where do we integrate this? voxpupuli/setup-vagrant?

Looking at it the DNS hook setup works nicely with systemd-resolved, and switching to qemu:///system fixes the bridge issue.
I was thinking it makes sense to move this into voxpupuli/setup-vagrant long term so other projects benefit too, maybe behind a flag like configure_libvirt_dns: true or libvirt_domain: example.com. Also would it make sense to log resolvectl status or virsh net-dumpxml in the workflow artifacts to help debug future DNS issues?

[ekohl]

This is now updated to set the management domain in Vagrantfile so you don't need to modify the network anymore. That makes it a fairly clean.

I've submitted it as voxpupuli/setup-vagrant#1. I've also learned systemd-resolved is present by default (at least in 24.04) so that can be skipped.