what is virtunixd ? Is there such a daemon?

Hello, as I experiment with virsh migration commands (and probably I do things that don't make sense), I got an error I could not understand: # virsh migrate centos7 unix:///tmp/netcat.sock error: Failed to connect socket to '/var/run/libvirt/virtunixd-sock': No such file or directory What is "/var/run/libvirt/virtunixd-sock" ? Should I have a "virtunixd" process running? I am building with non-modularized libvirtd currently, but I could not find a virtunixd module either... Thanks, Claudio