[ovirt-devel] qemu packaging - add the "qemu" user to a "gluster" group?

[Sandro Bonazzola]

On Wed, Apr 26, 2017 at 3:36 PM, Niels de Vos <ndevos at redhat.com> wrote:

> Hi,
>
> We're trying to improve the debugability of Gluster backed VMs and one
> of the features for this is to be able to gather "statedumps". These
> statedumps include memory allocation details and other information about
> the Gluster client. QEMU is one of the applications that can be
> configured to use libgfapi.so Gluster client.
>
> Gluster provides the /var/run/gluster/ directory and the libgfapi.so
> library that qemu (in block/gluster.c) uses that. Would there be a
> problem for the "qemu" packages to use add the "qemu" user to a
> "gluster" group? I'm not sure yet how this is done for other packages
> with their own users, but there would be a dependent installation order
> of some kind (needs rpm triggers?).
>
> What is your opinion on this issue, or would you recommend an other
> approach?
>

Adding Miroslav, Karen and Doron.
I'm not sure about how libgfapi is consumed by qemu-kvm(-ev/-rhev) but if
its support is enable by default and doesn't require additional qemu-kvm
sub packages to be enabled, I would suggest to just follow
https://fedoraproject.org/wiki/Packaging:UsersAndGroups
and add the qemu user to the gluster group in %pre.

>From oVirt point of view, I think it shouldn't affect us very much. On
CentOS Virt SIG we'll consume whatever will come from qemu-kvm-rhev.



>
> Thanks,
> Niels
>
> PS: https://bugzilla.redhat.com/1445569 can be used to reply as well
>
>
> From http://lists.gluster.org/pipermail/gluster-devel/2017-
> April/052629.html:
> On Tue, Apr 25, 2017 at 07:53:06PM +0200, Niels de Vos wrote:
> > Hi,
> >
> > Recently a new ability to trigger statedumps through the Gluster-CLI [0]
> > has been added. This makes it possible to get statedump from
> > applications that use gfapi. By default, statedumps are saved under
> > /var/run/gluster/... and this directory is only writable by root.
> > Applications that use gfapi do not require root permissions (like QEMU),
> > and therefore fail to write the statedump :-/
> >
> > One approach would be to create a "gluster" group and give the group
> > permissions to write to /var/run/gluster/... Other 'fixes' include
> > setting ACLs on the directory so that specified users can write there.
> > because many daemons have a "home directory" that does not exist, it
> > probably is not a good idea to use $HOME to store statedumps.
> >
> > What suggestions do others have?
> >
> > Thanks,
> > Niels
> >
> >
> > 0. https://github.com/gluster/glusterfs/blob/master/doc/
> debugging/statedump.md
>
>
>


-- 

SANDRO BONAZZOLA

ASSOCIATE MANAGER, SOFTWARE ENGINEERING, EMEA ENG VIRTUALIZATION R&D

Red Hat EMEA <https://www.redhat.com/>
<https://red.ht/sig>
TRIED. TESTED. TRUSTED. <https://redhat.com/trusted>
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