[lxc-users] Installing nfs-kernel-server in lxc 2.0 xenial fails with "systemd[1]: Failed to reset devices.list on /system.slice/dev-lxc-tty4.mount: Operation not permitted"

[Dan Kegel]

Trying to install a package that depends on having an nfs server ran
into trouble, so I tried a simple test case:

$ sudo lxc-create -n nfstest -t download -- -d ubuntu -r xenial -a amd64
$ sudo lxc-start -n nfstest
$ sudo lxc-attach -n nfstest apt-get update
$ sudo lxc-attach -n nfstest apt-get install nfs-kernel-server
...
Creating config file /etc/idmapd.conf with new version

Creating config file /etc/default/nfs-common with new version
Adding system user `statd' (UID 106) ...
Adding new user `statd' (UID 106) with group `nogroup' ...
Not creating home directory `/var/lib/nfs'.
nfs-utils.service is a disabled or a static unit, not starting it.
Setting up nfs-kernel-server (1:1.2.8-9ubuntu12) ...
A dependency job for nfs-server.service failed. See 'journalctl -xe'
for details.
nfs-server.service couldn't start.

Creating config file /etc/exports with new version

Creating config file /etc/default/nfs-kernel-server with new version
A dependency job for nfs-server.service failed. See 'journalctl -xe'
for details.
invoke-rc.d: initscript nfs-kernel-server, action "start" failed.
dpkg: error processing package nfs-kernel-server (--configure):
 subprocess installed post-installation script returned error exit status 1
Processing triggers for libc-bin (2.23-0ubuntu3) ...
Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for systemd (229-4ubuntu4) ...
Errors were encountered while processing:
 nfs-kernel-server
E: Sub-process /usr/bin/dpkg returned an error code (1)

$ sudo lxc-attach -n nfstest -- journalctl -xe
Apr 26 19:13:18 nfstest systemd[1]: Failed to reset devices.list on
/system.slice/dev-lxc-tty4.mount: Operation not permitted
Apr 26 19:13:18 nfstest systemd[1]: Failed to reset devices.list on
/system.slice/cron.service: Operation not permitted
Apr 26 19:13:18 nfstest systemd[1]: Failed to reset devices.list on
/system.slice/systemd-remount-fs.service: Operation not permitted
Apr 26 19:13:18 nfstest systemd[1]: Failed to reset devices.list on
/system.slice/system-container\x2dgetty.slice: Operation not permitted
Apr 26 19:13:18 nfstest systemd[1]: Failed to reset devices.list on
/system.slice/dev-lxc-tty2.mount: Operation not permitted
Apr 26 19:13:18 nfstest systemd[1]: Failed to reset devices.list on
/system.slice/sys-fs-fuse-connections.mount: Operation not permitted
Apr 26 19:13:18 nfstest systemd[1]: Failed to reset devices.list on
/system.slice/proc-sysrq\x2dtrigger.mount: Operation not permitted
Apr 26 19:13:18 nfstest systemd[1]: Failed to reset devices.list on
/system.slice/dev-lxc-tty1.mount: Operation not permitted
Apr 26 19:13:18 nfstest systemd[1]: Failed to reset devices.list on
/system.slice/dev-hugepages.mount: Operation not permitted
Apr 26 19:13:18 nfstest systemd[1]: run-rpc_pipefs.mount: Mount
process exited, code=exited status=32
Apr 26 19:13:18 nfstest systemd[1]: Failed to mount RPC Pipe File System.
-- Subject: Unit run-rpc_pipefs.mount has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit run-rpc_pipefs.mount has failed.
-- 
-- The result is failed.
...

Halp!  :-)   I'm sure it's some cgroups magic, and the answer will be
"Of course, you need to run lxc-cgroup as follows..."