Red Hat Bugzilla – Bug 1018730
Add workaround for systemd failing to remove cgroups on VM shutdown
Last modified: 2014-06-17 20:57:30 EDT
Description of problem:
systemd-machined will often fail to remove cgroups during VM shutdown. This will then prevent libvirtd starting the VM again until the host is rebooted. This problem appears to affect LXC guests quite alot more than KVM guests, for reasons unknown.
It will become a big problem for RHEL-7 when LXC error reporting is fixed per this bug
The workaround is upstream already
Author: Cédric Bosdonnat <email@example.com>
Date: Mon Sep 30 16:46:29 2013 +0200
LXC: workaround machined uncleaned data with containers running systemd.
The problem is described by  but its effect on libvirt is that
starting a container with a full distro running systemd after having
stopped it simply fails.
The container cleanup now calls the machined Terminate function to make
sure that everything is in order for the next run.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. virsh -c lxc:/// start guest
2. virsh -c lxc:/// destroy guest
3. goto step 1
Eventually 'start' will fail with an error about cgroups (if you are lucky).
Hi Daniel ,
I still can't meet the error after downgrade the libvirt , systemd , kernel to previous version.
With the command , run 30 minutes
# while true ; do virsh -c lxc:/// start test ; virsh -c lxc:/// destroy test ; done
Does any other packages related to this issue else ?
Or is there an effective way to reproduce the cgroup error with libvirt?
(In reply to time.su from comment #3)
> Hi Daniel ,
> I still can't meet the error after downgrade the libvirt , systemd , kernel
> to previous version.
> With the command , run 30 minutes
> # while true ; do virsh -c lxc:/// start test ; virsh -c lxc:/// destroy
> test ; done
> Does any other packages related to this issue else ?
> Or is there an effective way to reproduce the cgroup error with libvirt?
> Thanks .
It turns out that the key thing is that you want to have systemd itself running inside the container. The best way to get this setup is to use libvirt-sandbox eg
virt-sandbox-service create -u httpd.service myapache
and then do your 'while true' loop using the 'myapache' guest.
Thanks your kindly help , Daniel.
Verify this bug with libvirt-1.1.1-16.el7.x86_64
#virt-sandbox-service create -u httpd.service myapache
#while true ; do virsh -c lxc:/// start myapache ; virsh -c lxc:/// destroy myapache ; done
Expected:the container can be started and destroyed successfully
The steps will cause
1.systemd crashed and generate core dump by abrtd
Assertion 'n_pids > 0' failed at src/shared/cgroup-show.c:47, function show_pid_array(). Aborting.
Aborted (core dumped)
3.The container fail to start again due systemd has gone away.
This request was resolved in Red Hat Enterprise Linux 7.0.
Contact your manager or support representative in case you have further questions about the request.