On 3/15/16, 3:56 PM, "linux-lvm-bounces@redhat.com on behalf of Zdenek Kabelac" <linux-lvm-bounces@redhat.com on behalf of zdenek.kabelac@gmail.com> wrote: >Dne 15.3.2016 v 23:31 Serguei Bezverkhi (sbezverk) napsal(a): >> Hello folks, >> >> While trying to make lvm work within a docker container I came across >>an issue when all lvcreate/lvremove got stuck indefinetly or until >>control-c. When I checked process I noticed lvm was waiting on one >>semaphore, I found that other folks hit similar issue and they fixed it >>by setting udev_sync and udev_rules to 0. It also helped my case too. >> >> I would greatly appreciate if you could share your thought if this >>change in future can potentially have any negative impact. >> >> Thank you > >Hi > > >To 'unblock' stuck processes waiting on udev cookie - you could run: > >'dmsetup udevcomplete_all' > > >However the key question is - how you could get stuck. >That may need further debugging. > >You would need to expose your OS version and also version of lvm2 in use. > >Non working cookies are bad - and disabling udev sync is even more bad >idea... Zdeknek, To expand on what Serguei is doing, he is working on a patch to add LVM2+Iscsi in a container for the Cinder (block storage AAS) project in OpenStack. He is doing this in the upstream repository here: http://github.com/openstack/klla The LVM processes are running within a container. I suspect if the process is stuck on a semaphore it has something to do with semaphores not being shared with the host OS, because containers naturally create a contained environment. There are solutions for things like sockets, but not necessarily for things like semaphores for the container to communicate with the host OS. Is there another mechanism besides semaphores to get lvm2 to communicate with udev? Turning off udev sync side-steps the problem because then udev is not in the picture. Some people in our community think this is a security risk, although we assume the servers are completely secure. Your advice welcome on how to solve the problem would be mighty nice :) To see the change in full, check out: https://review.openstack.org/#/c/291285/ Regards, -steve > >Regards > >Zdenek > > >_______________________________________________ >linux-lvm mailing list >linux-lvm@redhat.com >https://www.redhat.com/mailman/listinfo/linux-lvm >read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
