Re: [ovirt-users] Hosted engine on gluster problem

Sandro, any word here? Btw, I'm not talking about hyperconvergency in this case, but 3 external gluster nodes using replica 3 Regards Luiz Em qua, 13 de abr de 2016 10:34, Luiz Claudio Prazeres Goncalves < luizcpg(a)gmail.com&gt; escreveu: > 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 > > > Missing option on the "hosted-engine --deploy" flow : > backupvolfile-server=gluster2.xyz.com > ,fetch-attempts=3,log-level=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(a)redhat.com&gt;: > >> >> >> On Tue, Apr 12, 2016 at 6:47 PM, Nir Soffer <nsoffer(a)redhat.com&gt; wrote: >> >>> On Tue, Apr 12, 2016 at 3:05 PM, Luiz Claudio Prazeres Goncalves >>> <luizcpg(a)gmail.com&gt; 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(a)redhat.com&gt; >>> > escreveu: >>> >> >>> >> On Mon, Apr 11, 2016 at 11:44 PM, Bond, Darryl <dbond(a)nrggos.com.au&gt; >>> >> 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(a)redhat.com&gt; >>> >>> 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@tbi.univie.ac.at<mailto:hawk@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@ovirt.org<mailto:users@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 >>> >>> > >>> >>> > >>> >>> > >>> >>> > >>> >>> > ________________________________ >>> >>> > >>> >>> > The contents of this electronic message and any attachments are >>> >>> > intended only for the addressee and may contain legally >>> privileged, >>> >>> > personal, sensitive or confidential information. 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Powered by community >>> collaboration. >>> >> See how it works at redhat.com >>> >> _______________________________________________ >>> >> Users mailing list >>> >> Users(a)ovirt.org >>> >> http://lists.ovirt.org/mailman/listinfo/users >>> > >>> > >>> > _______________________________________________ >>> > Users mailing list >>> > Users(a)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 >> > >