lxc-start occasionally fails on cgmanager_move_pid_sync during initialization

[teague-]

We have been occasionally seeing containers fail to boot in our continuous
integration system due to the following error:

lxc-start 1408141187.084 ERROR    lxc_cgmanager - call to cgmanager_move_pid_sync failed: invalid request

It happens only to one container during our startup process (of which we have
~30) seemingly at random, but to a particular container config and fails the
build. This only happens about 1/100 times, which suggests a race condition in
cgroup creation between the cgroup and lxc_cgmanager, but I haven't been able
to chase the error much farther than that.

This report on the mailing list was the only related report I found: https://lists.linuxcontainers.org/pipermail/lxc-users/2014-February/006252.html
However on inspection it 1) does not look like it was resolved and 2) is not totally related (the problems are different)

We use a lowlatency kernel on Ubuntu 12.04:
Ubuntu 3.2.0-58.60-lowlatency 3.2.53
and are currently on lxc 1.0.4-0ubuntu2 (the backport to ubuntu 12)

We make heavy use of the RR scheduler, setting cpu.rt_runtime_us on all
our cgroups.

Here's an example lxc config minus the nfs mounts and networking:

#
# generated by lxcrunner
#

# root filesystem location
lxc.rootfs = /tmp/tmpJe1KzL/fs/container1

# real-time runtime to enable chrt
lxc.cgroup.cpu.rt_runtime_us = 18765

# general
lxc.tty = 1

lxc.haltsignal = SIGKILL

[CameronNemo]

Are you still able to reproduce this with recent versions of both cgmanager and LXC? Maybe it has been fixed in the past few months... hopeful me :)

[teague-]

Still happening with:

$ dpkg -l | grep lxc
ii  lxc   1.0.7-0ubuntu0.1~ubuntu12.04.1~ppa1     Linux Containers userspace tools

[brunetto]

Hi!
I started today trying to use lxc and ran into this problem... I also read bug1413927 and other similar issues around...
I still can't understand if there's a fix and how to fix it...

[daald]

Same problem here (but it happens always on 15.04 vivid). I hope, together we can solve this problem... http://askubuntu.com/questions/623789/problem-setting-up-a-user-space-lxc-container

[brauner]

cgmanager is now officially deprecated (https://s3hh.wordpress.com/2016/06/18/whither-cgmanager/).