The libvirt LXC driver provides the ability to pass across pre-opened file
descriptors when starting LXC guests. This allows for libvirt LXC to support
systemd's `socket activation
-capability <http://0pointer.de/blog/projects/socket-activated-containers.html>`__,
+capability <https://0pointer.de/blog/projects/socket-activated-containers.html>`__,
where an incoming client connection in the host OS will trigger the startup of a
container, which runs another copy of systemd which gets passed the server
socket, and then activates the actual service handler in the container.