I had to chattr +i /etc/resolv.conf because my resolv.conf would keep getting truncated (as in empty) every time I restarted an lxd container. Rock solid my ass.
Maybe I'm wrong, but that just seems to show that if you want to resolve lxd domains (hostnames?), you need to inform systemd-resolved to ask lxd for those domains, which is... sensible?
> you should notify resolved of the domains that LXD can resolve
You'd have the same issues if you replaced systemd-resolved with e.g. dnsmasq. Split DNS always needs resolver configuration.
I think it's just someone unhappy that they used to be able to edit resolve.conf before systemd-resolved took it over. I recall being annoyed about it as well, but that was some time ago.