[ovirt-users] Hosted engine on gluster problem

Fri Aug 26 02:54:24 EDT 2016

On Tue, Aug 23, 2016 at 8:44 PM, David Gossage <dgossage at carouselchecks.com>
wrote:

>
> On Fri, Apr 15, 2016 at 8:00 AM, Luiz Claudio Prazeres Goncalves <
> luizcpg at gmail.com> wrote:
>
>> I'm not planning to move to ovirt 4 until it gets stable, so would be
>> great to backport to 3.6 or ,ideally, gets developed on the next release of
>> 3.6 branch. Considering the urgency (its a single point of failure) x
>> complexity wouldn't be hard to make the proposed fix.
>>
>>
> Bumping old email sorry.  Looks like https://bugzilla.redhat.com/
> show_bug.cgi?id=1298693 was finished against 3.6.7 according to that RFE.
>
> So does that mean if I add appropriate lines to my
>  /etc/ovirt-hosted-engine/hosted-engine.conf the next time I restart
> engine and agent/brokers to mount that storage point it will utilize the
> backupvol-server features?
>
> If so are appropriate settings outlined in docs somewhere?
>
> Running ovirt 3.6.7 and gluster 3.8.2 on centos 7 nodes.
>

Adding Simone

>
>
> I'm using today a production environment on top of gluster replica 3 and
>> this is the only SPF I have.
>>
>> Thanks
>> Luiz
>>
>> Em sex, 15 de abr de 2016 03:05, Sandro Bonazzola <sbonazzo at redhat.com>
>> escreveu:
>>
>>> On Thu, Apr 14, 2016 at 7:35 PM, Nir Soffer <nsoffer at redhat.com> wrote:
>>>
>>>> On Wed, Apr 13, 2016 at 4:34 PM, Luiz Claudio Prazeres Goncalves
>>>> <luizcpg at gmail.com> wrote:
>>>> > Nir, here is the problem:
>>>> > https://bugzilla.redhat.com/show_bug.cgi?id=1298693
>>>> >
>>>> > When you do a hosted-engine --deploy and pick "glusterfs" you don't
>>>> have a
>>>> > way to define the mount options, therefore, the use of the
>>>> > "backupvol-server", however when you create a storage domain from the
>>>> UI you
>>>> > can, like the attached screen shot.
>>>> >
>>>> >
>>>> > In the hosted-engine --deploy, I would expect a flow which includes
>>>> not only
>>>> > the "gluster" entrypoint, but also the gluster mount options which is
>>>> > missing today. This option would be optional, but would remove the
>>>> single
>>>> > point of failure described on the Bug 1298693.
>>>> >
>>>> > for example:
>>>> >
>>>> > Existing entry point on the "hosted-engine --deploy" flow
>>>> > gluster1.xyz.com:/engine
>>>>
>>>> I agree, this feature must be supported.
>>>>
>>>
>>> It will, and it's currently targeted to 4.0.
>>>
>>>
>>>
>>>>
>>>> > Missing option on the "hosted-engine --deploy" flow :
>>>> > backupvolfile-server=gluster2.xyz.com,fetch-attempts=3,log-l
>>>> evel=WARNING,log-file=/var/log/glusterfs/gluster_engine_domain.log
>>>> >
>>>> > Sandro, it seems to me a simple solution which can be easily fixed.
>>>> >
>>>> > What do you think?
>>>> >
>>>> > Regards
>>>> > -Luiz
>>>> >
>>>> >
>>>> >
>>>> > 2016-04-13 4:15 GMT-03:00 Sandro Bonazzola <sbonazzo at redhat.com>:
>>>> >>
>>>> >>
>>>> >>
>>>> >> On Tue, Apr 12, 2016 at 6:47 PM, Nir Soffer <nsoffer at redhat.com>
>>>> wrote:
>>>> >>>
>>>> >>> On Tue, Apr 12, 2016 at 3:05 PM, Luiz Claudio Prazeres Goncalves
>>>> >>> <luizcpg at gmail.com> wrote:
>>>> >>> > Hi Sandro, I've been using gluster with 3 external hosts for a
>>>> while
>>>> >>> > and
>>>> >>> > things are working pretty well, however this single point of
>>>> failure
>>>> >>> > looks
>>>> >>> > like a simple feature to implement,but critical to anyone who
>>>> wants to
>>>> >>> > use
>>>> >>> > gluster on production  . This is not hyperconvergency which has
>>>> other
>>>> >>> > issues/implications. So , why not have this feature out on 3.6
>>>> branch?
>>>> >>> > It
>>>> >>> > looks like just let vdsm use the 'backupvol-server' option when
>>>> >>> > mounting the
>>>> >>> > engine domain and make the property tests.
>>>> >>>
>>>> >>> Can you explain what is the problem, and what is the suggested
>>>> solution?
>>>> >>>
>>>> >>> Engine and vdsm already support the backupvol-server option - you
>>>> can
>>>> >>> define this option in the storage domain options when you create a
>>>> >>> gluster
>>>> >>> storage domain. With this option vdsm should be able to connect to
>>>> >>> gluster
>>>> >>> storage domain even if a brick is down.
>>>> >>>
>>>> >>> If you don't have this option in engine , you probably cannot add
>>>> it with
>>>> >>> hosted
>>>> >>> engine setup, since for editing it you must put the storage domain
>>>> in
>>>> >>> maintenance
>>>> >>> and if you do this the engine vm will be killed :-) This is is one
>>>> of
>>>> >>> the issues with
>>>> >>> engine managing the storage domain it runs on.
>>>> >>>
>>>> >>> I think the best way to avoid this issue, is to add a DNS entry
>>>> >>> providing the addresses
>>>> >>> of all the gluster bricks, and use this address for the gluster
>>>> >>> storage domain. This way
>>>> >>> the glusterfs mount helper can mount the domain even if one of the
>>>> >>> gluster bricks
>>>> >>> are down.
>>>> >>>
>>>> >>> Again, we will need some magic from the hosted engine developers to
>>>> >>> modify the
>>>> >>> address of the hosted engine gluster domain on existing system.
>>>> >>
>>>> >>
>>>> >> Magic won't happen without a bz :-) please open one describing what's
>>>> >> requested.
>>>> >>
>>>> >>
>>>> >>>
>>>> >>>
>>>> >>> Nir
>>>> >>>
>>>> >>> >
>>>> >>> > Could you add this feature to the next release of 3.6 branch?
>>>> >>> >
>>>> >>> > Thanks
>>>> >>> > Luiz
>>>> >>> >
>>>> >>> > Em ter, 12 de abr de 2016 05:03, Sandro Bonazzola <
>>>> sbonazzo at redhat.com>
>>>> >>> > escreveu:
>>>> >>> >>
>>>> >>> >> On Mon, Apr 11, 2016 at 11:44 PM, Bond, Darryl <
>>>> dbond at nrggos.com.au>
>>>> >>> >> wrote:
>>>> >>> >>>
>>>> >>> >>> My setup is hyperconverged. I have placed my test results in
>>>> >>> >>> https://bugzilla.redhat.com/show_bug.cgi?id=1298693
>>>> >>> >>>
>>>> >>> >>
>>>> >>> >> Ok, so you're aware about the limitation of the single point of
>>>> >>> >> failure.
>>>> >>> >> If you drop the host referenced in hosted engine configuration
>>>> for the
>>>> >>> >> initial setup it won't be able to connect to shared storage even
>>>> if
>>>> >>> >> the
>>>> >>> >> other hosts in the cluster are up since the entry point is down.
>>>> >>> >> Note that hyperconverged deployment is not supported in 3.6.
>>>> >>> >>
>>>> >>> >>
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> Short description of setup:
>>>> >>> >>>
>>>> >>> >>> 3 hosts with 2 disks each set up with gluster replica 3 across
>>>> the 6
>>>> >>> >>> disks volume name hosted-engine.
>>>> >>> >>>
>>>> >>> >>> Hostname hosted-storage configured in /etc//hosts to point to
>>>> the
>>>> >>> >>> host1.
>>>> >>> >>>
>>>> >>> >>> Installed hosted engine on host1 with the hosted engine storage
>>>> path
>>>> >>> >>> =
>>>> >>> >>> hosted-storage:/hosted-engine
>>>> >>> >>>
>>>> >>> >>> Install first engine on h1 successful. Hosts h2 and h3 added to
>>>> the
>>>> >>> >>> hosted engine. All works fine.
>>>> >>> >>>
>>>> >>> >>> Additional storage and non-hosted engine hosts added etc.
>>>> >>> >>>
>>>> >>> >>> Additional VMs added to hosted-engine storage (oVirt Reports VM
>>>> and
>>>> >>> >>> Cinder VM). Additional VM's are hosted by other storage -
>>>> cinder and
>>>> >>> >>> NFS.
>>>> >>> >>>
>>>> >>> >>> The system is in production.
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> Engine can be migrated around with the web interface.
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> - 3.6.4 upgrade released, follow the upgrade guide, engine is
>>>> >>> >>> upgraded
>>>> >>> >>> first , new Centos kernel requires host reboot.
>>>> >>> >>>
>>>> >>> >>> - Engine placed on h2 -  h3 into maintenance (local) upgrade and
>>>> >>> >>> Reboot
>>>> >>> >>> h3 - No issues - Local maintenance removed from h3.
>>>> >>> >>>
>>>> >>> >>> - Engine placed on h3 -  h2 into maintenance (local) upgrade and
>>>> >>> >>> Reboot
>>>> >>> >>> h2 - No issues - Local maintenance removed from h2.
>>>> >>> >>>
>>>> >>> >>> - Engine placed on h3 -h1 into mainteance (local) upgrade and
>>>> reboot
>>>> >>> >>> h1 -
>>>> >>> >>> engine crashes and does not start elsewhere, VM(cinder)  on h3
>>>> on
>>>> >>> >>> same
>>>> >>> >>> gluster volume pauses.
>>>> >>> >>>
>>>> >>> >>> - Host 1 takes about 5 minutes to reboot (Enterprise box with
>>>> all
>>>> >>> >>> it's
>>>> >>> >>> normal BIOS probing)
>>>> >>> >>>
>>>> >>> >>> - Engine starts after h1 comes back and stabilises
>>>> >>> >>>
>>>> >>> >>> - VM(cinder) unpauses itself,  VM(reports) continued fine the
>>>> whole
>>>> >>> >>> time.
>>>> >>> >>> I can do no diagnosis on the 2 VMs as the engine is not
>>>> available.
>>>> >>> >>>
>>>> >>> >>> - Local maintenance removed from h1
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> I don't believe the issue is with gluster itself as the volume
>>>> >>> >>> remains
>>>> >>> >>> accessible on all hosts during this time albeit with a missing
>>>> server
>>>> >>> >>> (gluster volume status) as each gluster server is rebooted.
>>>> >>> >>>
>>>> >>> >>> Gluster was upgraded as part of the process, no issues were seen
>>>> >>> >>> here.
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> I have been able to duplicate the issue without the upgrade by
>>>> >>> >>> following
>>>> >>> >>> the same sort of timeline.
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> ________________________________
>>>> >>> >>> From: Sandro Bonazzola <sbonazzo at redhat.com>
>>>> >>> >>> Sent: Monday, 11 April 2016 7:11 PM
>>>> >>> >>> To: Richard Neuboeck; Simone Tiraboschi; Roy Golan; Martin
>>>> Sivak;
>>>> >>> >>> Sahina
>>>> >>> >>> Bose
>>>> >>> >>> Cc: Bond, Darryl; users
>>>> >>> >>> Subject: Re: [ovirt-users] Hosted engine on gluster problem
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> On Mon, Apr 11, 2016 at 9:37 AM, Richard Neuboeck
>>>> >>> >>> <hawk at tbi.univie.ac.at<mailto:hawk at tbi.univie.ac.at>> wrote:
>>>> >>> >>> Hi Darryl,
>>>> >>> >>>
>>>> >>> >>> I'm still experimenting with my oVirt installation so I tried to
>>>> >>> >>> recreate the problems you've described.
>>>> >>> >>>
>>>> >>> >>> My setup has three HA hosts for virtualization and three
>>>> machines
>>>> >>> >>> for the gluster replica 3 setup.
>>>> >>> >>>
>>>> >>> >>> I manually migrated the Engine from the initial install host
>>>> (one)
>>>> >>> >>> to host three. Then shut down host one manually and interrupted
>>>> the
>>>> >>> >>> fencing mechanisms so the host stayed down. This didn't bother
>>>> the
>>>> >>> >>> Engine VM at all.
>>>> >>> >>>
>>>> >>> >>> Did you move the host one to maintenance before shutting down?
>>>> >>> >>> Or is this a crash recovery test?
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> To make things a bit more challenging I then shut down host
>>>> three
>>>> >>> >>> while running the Engine VM. Of course the Engine was down for
>>>> some
>>>> >>> >>> time until host two detected the problem. It started the Engine
>>>> VM
>>>> >>> >>> and everything seems to be running quite well without the
>>>> initial
>>>> >>> >>> install host.
>>>> >>> >>>
>>>> >>> >>> Thanks for the feedback!
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> My only problem is that the HA agent on host two and three
>>>> refuse to
>>>> >>> >>> start after a reboot due to the fact that the configuration of
>>>> the
>>>> >>> >>> hosted engine is missing. I wrote another mail to
>>>> >>> >>> users at ovirt.org<mailto:users at ovirt.org>
>>>> >>> >>> about that.
>>>> >>> >>>
>>>> >>> >>> This is weird. Martin,  Simone can you please investigate on
>>>> this?
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> Cheers
>>>> >>> >>> Richard
>>>> >>> >>>
>>>> >>> >>> On 04/08/2016 01:38 AM, Bond, Darryl wrote:
>>>> >>> >>> > There seems to be a pretty severe bug with using hosted
>>>> engine on
>>>> >>> >>> > gluster.
>>>> >>> >>> >
>>>> >>> >>> > If the host that was used as the initial hosted-engine
>>>> --deploy
>>>> >>> >>> > host
>>>> >>> >>> > goes away, the engine VM wil crash and cannot be restarted
>>>> until
>>>> >>> >>> > the host
>>>> >>> >>> > comes back.
>>>> >>> >>>
>>>> >>> >>> is this an Hyperconverged setup?
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> >
>>>> >>> >>> > This is regardless of which host the engine was currently
>>>> running.
>>>> >>> >>> >
>>>> >>> >>> >
>>>> >>> >>> > The issue seems to be buried in the bowels of VDSM and is not
>>>> an
>>>> >>> >>> > issue
>>>> >>> >>> > with gluster itself.
>>>> >>> >>>
>>>> >>> >>> Sahina, can you please investigate on this?
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> >
>>>> >>> >>> > The gluster filesystem is still accessable from the host that
>>>> was
>>>> >>> >>> > running the engine. The issue has been submitted to bugzilla
>>>> but
>>>> >>> >>> > the fix is
>>>> >>> >>> > some way off (4.1).
>>>> >>> >>> >
>>>> >>> >>> >
>>>> >>> >>> > Can my hosted engine be converted to use NFS (using the
>>>> gluster NFS
>>>> >>> >>> > server on the same filesystem) without rebuilding my hosted
>>>> engine
>>>> >>> >>> > (ie
>>>> >>> >>> > change domainType=glusterfs to domainType=nfs)?
>>>> >>> >>>
>>>> >>> >>> >
>>>> >>> >>> > What effect would that have on the hosted-engine storage
>>>> domain
>>>> >>> >>> > inside
>>>> >>> >>> > oVirt, ie would the same filesystem be mounted twice or would
>>>> it
>>>> >>> >>> > just break.
>>>> >>> >>> >
>>>> >>> >>> >
>>>> >>> >>> > Will this actually fix the problem, does it have the same
>>>> issue
>>>> >>> >>> > when
>>>> >>> >>> > the hosted engine is on NFS?
>>>> >>> >>> >
>>>> >>> >>> >
>>>> >>> >>> > Darryl
>>>> >>> >>> >
>>>> >>> >>> >
>>>> >>> >>> >
>>>> >>> >>> >
>>>> >>> >>> > ________________________________
>>>> >>> >>> >
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>>>> >>> >>> >
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> --
>>>> >>> >>> /dev/null
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> _______________________________________________
>>>> >>> >>> Users mailing list
>>>> >>> >>> Users at ovirt.org<mailto:Users at ovirt.org>
>>>> >>> >>> http://lists.ovirt.org/mailman/listinfo/users
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>>
>>>> >>> >>> --
>>>> >>> >>> Sandro Bonazzola
>>>> >>> >>> Better technology. Faster innovation. Powered by community
>>>> >>> >>> collaboration.
>>>> >>> >>> See how it works at redhat.com<http://redhat.com>
>>>> >>> >>
>>>> >>> >>
>>>> >>> >>
>>>> >>> >>
>>>> >>> >> --
>>>> >>> >> Sandro Bonazzola
>>>> >>> >> Better technology. Faster innovation. Powered by community
>>>> >>> >> collaboration.
>>>> >>> >> See how it works at redhat.com
>>>> >>> >> _______________________________________________
>>>> >>> >> Users mailing list
>>>> >>> >> Users at ovirt.org
>>>> >>> >> http://lists.ovirt.org/mailman/listinfo/users
>>>> >>> >
>>>> >>> >
>>>> >>> > _______________________________________________
>>>> >>> > Users mailing list
>>>> >>> > Users at ovirt.org
>>>> >>> > http://lists.ovirt.org/mailman/listinfo/users
>>>> >>> >
>>>> >>
>>>> >>
>>>> >>
>>>> >>
>>>> >> --
>>>> >> Sandro Bonazzola
>>>> >> Better technology. Faster innovation. Powered by community
>>>> collaboration.
>>>> >> See how it works at redhat.com
>>>> >
>>>> >
>>>>
>>>
>>>
>>>
>>> --
>>> Sandro Bonazzola
>>> Better technology. Faster innovation. Powered by community collaboration.
>>> See how it works at redhat.com
>>>
>>
>> _______________________________________________
>> Users mailing list
>> Users at ovirt.org
>> http://lists.ovirt.org/mailman/listinfo/users
>>
>>
>

-- 
Sandro Bonazzola
Better technology. Faster innovation. Powered by community collaboration.
See how it works at redhat.com
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