Richard Weinberger [off-list ref] writes:

Am 28.05.2015 um 16:08 schrieb Serge Hallyn:

quoted

Quoting Andy Lutomirski (luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org):

quoted

On Fri, May 22, 2015 at 10:39 AM, Eric W. Biederman
[off-list ref] wrote:

quoted

I had hoped to get some Tested-By's on that patch series.

Sorry, I've been totally swamped.

I suspect that Sandstorm is okay, but I haven't had a chance to test
it for real.  Sandstorm makes only limited use of proc and sysfs in
containers, but I'll see if I can test it for real this weekend.

Testing this with unprivileged containers, I get

lxc-start: conf.c: lxc_mount_auto_mounts: 808 Operation not permitted - error mounting sysfs on /usr/lib/x86_64-linux-gnu/lxc/sys/devices/virtual/net flags 0

FWIW, it breaks also libvirt-lxc:
Error: internal error: guest failed to start: Failed to re-mount /proc/sys on /proc/sys flags=1021: Operation not permitted

Interesting.  I had not anticipated a failure there?  And it is failing
in remount?  Oh that is interesting.

That implies that there is some flag of the original mount of /proc that
the remount of /proc/sys is clearing, and that previously 

The flags specified are current rdonly,remount,bind so I expect there
are some other flags on proc that libvirt-lxc is clearing by accident
and we did not fail before because the kernel was not enforcing things.

What are the mount flags in a working libvirt-lxc?

Eric