Comment # 3 on bug 1183247 from James Fehlig

(In reply to Stefan Eisenwiener from comment #2)
> tumbleweed-20210302 still working
> tumbleweed-20210305 shows the issue
> - libvirt         was updated from 7.0.0  to 7.1.0

Thanks for bisecting to this point! I've bisected libvirt between these
releases and found commit 9c1693eff4 introduced the problem. When starting an
LXC container, virLXCProcessStart() calls virCgroupNewDetectMachine(), which
now calls virSystemdGetMachineUnitByPID(). The latter fails, even though the
container process should be running since handshake with the lxc driver has
already occurred. Investigating...