[lxc-users] lxc-execute with read-only rootfs

[Antonin Bas]

Hi,

I am trying to run an application container with lxc-execute. I am
going to run "untrusted" student codes in this container and I want
the root file system to be shared with the host but read-only. I
thought this would be as easy as using the following configuration
file:

# Container with new network withtout network devices
lxc.utsname = omega
lxc.network.type = empty
lxc.network.flags = up

lxc.rootfs = /tmp/guest/rootfs
lxc.mount.entry=/ /tmp/guest/rootfs/ none ro,bind 0 0

However, when I run `sudo lxc-execute -n test -f grader.conf
--logpriority=DEBUG -- /bin/bash`, I get the following message:

lxc-execute: Read-only file system - error unlinking
/usr/lib/x86_64-linux-gnu/lxc/dev/kmsg

lxc-execute: failed to setup kmsg for 'test'
lxc-execute: Read-only file system - failed to create directory
'/usr/lib/x86_64-linux-gnu/lxc/lxc_putold'

lxc-execute: Read-only file system - failed to create pivotdir
'/usr/lib/x86_64-linux-gnu/lxc/lxc_putold'
lxc-execute: failed to setup pivot root
lxc-execute: failed to set rootfs for 'test'
lxc-execute: failed to setup the container
lxc-execute: invalid sequence number 1. expected 2
lxc-execute: failed to spawn 'test'


Is it possible to have some insight on what the problem is here?
I am using Ubuntu 13.10, and my lxc is the one from the official repo
(1.0.0.alpha1).

Thanks you in advance for your help,

Antonin