When using LAVA inside a docker container, the LXC support adds lots of unnecessary overhead since the docker images are already made to include the necessary tools. So having another container is pointless. Even worse, LXC doesn't work inside docker anyways.
The LXC support should be made optional for a given LAVA install.
Until LXC can be disabled, projects like lava-docker[1] simply cannot support fastboot devices which is a major problem.
Kevin