[ceph-users] QEMU/Libvirt + librbd issue using Luminous 12.2.7

Jason Dillaman jdillama at redhat.com
Tue Oct 2 10:54:32 PDT 2018


On Tue, Oct 2, 2018 at 1:48 PM Andre Goree <andre at drenet.net> wrote:
>
> On 2018/10/02 1:29 pm, Jason Dillaman wrote:
> > On Tue, Oct 2, 2018 at 1:25 PM Andre Goree <andre at drenet.net> wrote:
> >>
> >>
> >> Unfortunately, it would appear that I'm not getting anything in the
> >> logs
> >> _but_ the creation of the rbd image -- i.e., nothing regarding the
> >> attempt to attach it via libvirt.  Here are the logs, for the sake of
> >> clarity: https://pastebin.com/usAUspCa
> >>
> >>
> >> I think this might be a problem in libvirt and/or QEMU, in that
> >> case...but then why am I only seeing this _after_ an upgrade past
> >> 12.2.4; that makes me think something changed between 12.2.4 & 12.2.5,
> >> libvirt-related, that is causing this (I've not upgraded my libvirt
> >> version in months).
> >
> > AFAIK, you are the only person reporting a similar issue. Are you
> > confident that your libvirt / QEMU user has access to write to the
> > specified log location (both permissions and SElinux/AppArmor)?
> >
> >> OS: Ubuntu 16.04
> >> Libvirt ver: libvirtd (libvirt) 1.3.1
> >> Ceph ver:  12.2.8
> >>
> >
> >
> > --
> > Jason
>
>
> I'm actually not so sure the libvirt user has write access to the
> location -- will libvirt automatically try to write to the file (given
> that it's a setting in ceph.conf)?
>
> I just confirmed that the libvirt-qemu user could NOT write to the
> location I have defined (/var/log/ceph_client.log).
>
> After adjusting perms though, I still have nothing printed in the logs
> except the creation.

Technically, libvirt will just use QEMU's monitor protocol to instruct
an already running QEMU instance to attach the device. Therefore, it
really comes down to the permissions of that QEMU process.

> FWIW, I'm creating the rbd image with 'qemu-img create -f rbd
> rbd:$image_name $storage_size' and I'm attaching the image with 'virsh
> attach-device $vm_name $xml --persistent'
>
>
> --
> Andre Goree
> -=-=-=-=-=-
> Email     - andre at drenet.net
> Website   - http://blog.drenet.net
> PGP key   - http://www.drenet.net/pubkey.html
> -=-=-=-=-=-



-- 
Jason


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