After learning that the lxd launch command would hang on an Ubuntu 18.04 system that had some possibly conflicting software installed, I learned that similar problems result when lxd init is run on a fresh Ubuntu 18.04 KVM guest.

So what I'm going to be doing to deal with this is what I did with the aforementioned problem. I'm just going to use the Snap version of LXD, even though I hate using some newfangled thing called "Snap". But I'll get over that.

All I know is I typed lxd init in a terminal and pressed Enter about two minutes ago and I've seen nothing.

So, to remedy this, I'll replace the .deb package version of LXD that comes with Ubuntu 18.04 with the Snap (ugh) version of LXD.

It goes like this:

apt remove --purge lxd lxd-client

snap install lxd

So now that I've got the "Snap" version of LXD installed, I can finally initialize LXD without it hanging (hopefully) by logging out, and then logging back in and running...

lxd init

At this point lxd init worked without hanging.