[lxc-devel] Containers do not start with lxc-1.0.0.beta2 on RHEL-6.5

[Robert Vogelgesang]

Hello all,

since yesterday I'm testing lxc-1.0.0.beta2 on a RHEL-6.5, but I
failed to get any container to start.

I've set up a RHEL-6.5 test server with the "cgconfig" service enabled
in default configuration.  When I try to start a container (with root
privileges), I get:

# lxc-start -n test -d -o lxc-start.log -l DEBUG
lxc-start: command get_cgroup failed to receive response

The container did not start, and lxc-start.log has the following ERRORs:
(leading whitespace trimmed)

lxc-start 1389968577.048 ERROR    lxc_cgroup - Could not set clone_children to 1 for cpuset hierarchy in parent cgroup.
lxc-start 1389968577.048 ERROR    lxc_cgroup - Device or resource busy - cgroup_rmdir: failed to delete /cgroup/blkio/
lxc-start 1389968577.048 ERROR    lxc_cgroup - Device or resource busy - cgroup_rmdir: failed to delete /cgroup/net_cls/
lxc-start 1389968577.048 ERROR    lxc_cgroup - Device or resource busy - cgroup_rmdir: failed to delete /cgroup/freezer/
lxc-start 1389968577.048 ERROR    lxc_cgroup - Device or resource busy - cgroup_rmdir: failed to delete /cgroup/devices/
lxc-start 1389968577.048 ERROR    lxc_cgroup - Device or resource busy - cgroup_rmdir: failed to delete /cgroup/memory/
lxc-start 1389968577.048 ERROR    lxc_cgroup - Device or resource busy - cgroup_rmdir: failed to delete /cgroup/cpuacct/
lxc-start 1389968577.049 ERROR    lxc_cgroup - Device or resource busy - cgroup_rmdir: failed to delete /cgroup/cpu/
lxc-start 1389968577.049 ERROR    lxc_cgroup - Device or resource busy - cgroup_rmdir: failed to delete /cgroup/cpuset/
lxc-start 1389968577.049 ERROR    lxc_start - failed to create cgroups for 'test'
lxc-start 1389968577.078 ERROR    lxc_start - failed to spawn 'test'
lxc-start 1389968577.079 ERROR    lxc_commands - command get_cgroup failed to receive response


The first error comes from cgroup.c:lxc_cgroup_create().  When comparing
this with cgroup.c:set_clone_children() from lxc-0.9.0 I saw that 0.9.0
ignored errors when setting clone_children, and so I patched
cgroup.c:lxc_cgroup_create() to do the same.  But the container still did
not start.  The errors in lxc-start.log were now:

lxc-start 1389980209.248 ERROR    lxc_cgroup - No space left on device - Could not add pid 21347 to cgroup /lxc/test: internal error
lxc-start 1389980209.270 ERROR    lxc_start - failed to spawn 'test'
lxc-start 1389980209.271 ERROR    lxc_commands - command get_cgroup failed to receive response

Using strace(8), I found this:
open("/cgroup/cpuset/lxc/test/tasks", O_WRONLY|O_CREAT|O_TRUNC|O_CLOEXEC, 0666) = 11
write(11, "21347", 5)                   = -1 ENOSPC (No space left on device)
close(11)                               = 0

Switching back to lxc-0.9.0, this same container starts just fine.

0.9.0 has its own set of problems when used under RHEL-6.5, but containers
do at least start - and can be shut down again.  I had hoped that 1.0.0
would resolve the issues of 0.9.0...  (lxc-ps and lxc-netstat don't work)

So, my first question would be:  Is RHEL-6.5 (and CentOS 6.5, and others)
a "supported" platform for lxc-1.0.0?

And if so:  What should I do to debug this further?  Are there already
some patches I could test?


	Robert