We're using docker but want to implement userns to restrict root users in containers from having root access to the host (vm). However, on the ubuntu system, when we enable the userns setting in /etc/docker/daemon.json with a freeipa user, the docker daemon will not start. The user in question does resolve when doing lookups (getent passwd [username]) and the user can log on via ssh so authentication seems to be working in general. Changing the username to a local user causes the problem to go away. I've been trying to leverage Google but not having any success getting relevant results. If anyone can provide insight or suggest a solution I'd appreciate it.
Ubuntu 16.04 Docker 17.05.0-ce Kernel 4.4.0-141-generic Freeipa client version 4.3.1 SSSD version 1.13.4