[libvirt-users] libvirt_lxc namespace and umount in global namespace
Hi, I am currently having an issue with the libvirt_lxc binary that is launched when starting a lxc instance using libvirt. This process seems to have its own namespace for mounts. What happens is that if I umount something in the global namespace, it stays mounted in the libvirt_lxc namespace. I'm working with drbd, and after unmounting the mount point, I want to change the state of the drbd resource as Secondary. But if fails. Indeed, libvirt_lxc has still the resource which is mounted in its namespace. Currently, I wanted to test the setns tool to enter the namespace and umount the mount point. But I am currently on Ubuntu 12.04 with a 3.2.0-59 kernel which does not have /proc/[pid]/ns/mnt I can't upgrade to 3.8 (which have the proc mnt file) as the drbd tools are not compatible. Do you have an idea of what I could try ? Here I the steps I do to reproduce the issue: - Mount a drbd file system - Start a lxc instance with libvirt - Umount the drbd file system - Set the drbd resource as secondary. => Does not work
On Thu, Feb 20, 2014 at 01:47:52PM +0100, Olivier Nicaise wrote:
Hi,
I am currently having an issue with the libvirt_lxc binary that is launched when starting a lxc instance using libvirt. This process seems to have its own namespace for mounts. What happens is that if I umount something in the global namespace, it stays mounted in the libvirt_lxc namespace. I'm working with drbd, and after unmounting the mount point, I want to change the state of the drbd resource as Secondary. But if fails. Indeed, libvirt_lxc has still the resource which is mounted in its namespace.
Currently, I wanted to test the setns tool to enter the namespace and umount the mount point. But I am currently on Ubuntu 12.04 with a 3.2.0-59 kernel which does not have /proc/[pid]/ns/mnt I can't upgrade to 3.8 (which have the proc mnt file) as the drbd tools are not compatible.
Do you have an idea of what I could try ?
Ahh, interesting scenario that I'd not considered. With LXC there are in fact 3 mounts namespaces in play - The host OS namespace - The libvirt_lxc namespace - The actual container namespace The libvirt_lxc namespace is basically the same as the host namespace, but with the addition of a devpts for the container's /dev/pts. We explicitly don't allow dynamic changes to propagate from the host OS to the container namespace, however, it sounds like we *should* allow host OS changes to propagage to the libvirt_lxc process namespace. Can you file a bug about this, so it doesn't get forgotten. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
Thanks for your fast feedback! I created the bug: https://bugzilla.redhat.com/show_bug.cgi?id=1067489 2014-02-20 15:03 GMT+01:00 Daniel P. Berrange <berrange@redhat.com>:
On Thu, Feb 20, 2014 at 01:47:52PM +0100, Olivier Nicaise wrote:
Hi,
I am currently having an issue with the libvirt_lxc binary that is launched when starting a lxc instance using libvirt. This process seems to have its own namespace for mounts. What happens is that if I umount something in the global namespace, it stays mounted in the libvirt_lxc namespace. I'm working with drbd, and after unmounting the mount point, I want to change the state of the drbd resource as Secondary. But if fails. Indeed, libvirt_lxc has still the resource which is mounted in its namespace.
Currently, I wanted to test the setns tool to enter the namespace and umount the mount point. But I am currently on Ubuntu 12.04 with a 3.2.0-59 kernel which does not have /proc/[pid]/ns/mnt I can't upgrade to 3.8 (which have the proc mnt file) as the drbd tools are not compatible.
Do you have an idea of what I could try ?
Ahh, interesting scenario that I'd not considered. With LXC there are in fact 3 mounts namespaces in play
- The host OS namespace - The libvirt_lxc namespace - The actual container namespace
The libvirt_lxc namespace is basically the same as the host namespace, but with the addition of a devpts for the container's /dev/pts.
We explicitly don't allow dynamic changes to propagate from the host OS to the container namespace, however, it sounds like we *should* allow host OS changes to propagage to the libvirt_lxc process namespace. Can you file a bug about this, so it doesn't get forgotten.
Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/:| |: http://libvirt.org -o- http://virt-manager.org:| |: http://autobuild.org -o- http://search.cpan.org/~danberr/:| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc:|
participants (2)
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Daniel P. Berrange -
Olivier Nicaise