Re: [ovirt-users] hyperconverged question

Jim - here is my test: - All VM's on node2: hosted engine and 1 test VM - Test VM on gluster storage domain (with mount options set) - hosted engine is on gluster as well, with settings persisted to hosted-engine.conf for backupvol All VM's stayed up. Nothing in dmesg of the test vm indicating a pause or an issue or anything However, what I did notice during this, is my /datatest volume doesnt have quorum set. So I will set that now and report back what happens # gluster volume info datatest Volume Name: datatest Type: Replicate Volume ID: 229c25f9-405e-4fe7-b008-1d3aea065069 Status: Started Snapshot Count: 0 Number of Bricks: 1 x 3 = 3 Transport-type: tcp Bricks: Brick1: node1:/gluster/data/datatest/brick1 Brick2: node2:/gluster/data/datatest/brick1 Brick3: node3:/gluster/data/datatest/brick1 Options Reconfigured: transport.address-family: inet nfs.disable: on Perhaps quorum may be more trouble than its worth when you have 3 nodes and/or 2 nodes + arbiter? Since I am keeping my 3rd node out of ovirt, I am more content on keeping it as a warm spare if I **had** to swap it in to ovirt cluster, but keeps my storage 100% quorum On Fri, Sep 1, 2017 at 5:18 PM, Jim Kusznir <jim(a)palousetech.com&gt; wrote: > I can confirm that I did set it up manually, and I did specify backupvol, > and in the "manage domain" storage settings, I do have under mount > options, backup-volfile-servers=192.168.8.12:192.168.8.13 (and this was > done at initial install time). > > The "used managed gluster" checkbox is NOT checked, and if I check it and > save settings, next time I go in it is not checked. > > --Jim > > On Fri, Sep 1, 2017 at 2:08 PM, Charles Kozler <ckozleriii(a)gmail.com&gt; > wrote: > >> @ Jim - here is my setup which I will test in a few (brand new cluster) >> and report back what I found in my tests >> >> - 3x servers direct connected via 10Gb >> - 2 of those 3 setup in ovirt as hosts >> - Hosted engine >> - Gluster replica 3 (no arbiter) for all volumes >> - 1x engine volume gluster replica 3 manually configured (not using >> ovirt managed gluster) >> - 1x datatest volume (20gb) replica 3 manually configured (not using >> ovirt managed gluster) >> - 1x nfstest domain served from some other server in my infrastructure >> which, at the time of my original testing, was master domain >> >> I tested this earlier and all VMs stayed online. However, ovirt cluster >> reported DC/cluster down, all VM's stayed up >> >> As I am now typing this, can you confirm you setup your gluster storage >> domain with backupvol? Also, confirm you updated hosted-engine.conf with >> backupvol mount option as well? >> >> On Fri, Sep 1, 2017 at 4:22 PM, Jim Kusznir <jim(a)palousetech.com&gt; wrote: >> >>> So, after reading the first document twice and the 2nd link thoroughly >>> once, I believe that the arbitrator volume should be sufficient and count >>> for replica / split brain. EG, if any one full replica is down, and the >>> arbitrator and the other replica is up, then it should have quorum and all >>> should be good. >>> >>> I think my underlying problem has to do more with config than the >>> replica state. That said, I did size the drive on my 3rd node planning to >>> have an identical copy of all data on it, so I'm still not opposed to >>> making it a full replica. >>> >>> Did I miss something here? >>> >>> Thanks! >>> >>> On Fri, Sep 1, 2017 at 11:59 AM, Charles Kozler <ckozleriii(a)gmail.com&gt; >>> wrote: >>> >>>> These can get a little confusing but this explains it best: >>>> https://gluster.readthedocs.io/en/latest/Administrator >>>> %20Guide/arbiter-volumes-and-quorum/#replica-2-and-replica-3-volumes >>>> >>>> Basically in the first paragraph they are explaining why you cant have >>>> HA with quorum for 2 nodes. Here is another overview doc that explains some >>>> more >>>> >>>> http://openmymind.net/Does-My-Replica-Set-Need-An-Arbiter/ >>>> >>>> From my understanding arbiter is good for resolving split brains. >>>> Quorum and arbiter are two different things though quorum is a mechanism to >>>> help you **avoid** split brain and the arbiter is to help gluster resolve >>>> split brain by voting and other internal mechanics (as outlined in link 1). >>>> How did you create the volume exactly - what command? It looks to me like >>>> you created it with 'gluster volume create replica 2 arbiter 1 {....}' per >>>> your earlier mention of "replica 2 arbiter 1". That being said, if you did >>>> that and then setup quorum in the volume configuration, this would cause >>>> your gluster to halt up since quorum was lost (as you saw until you >>>> recovered node 1) >>>> >>>> As you can see from the docs, there is still a corner case for getting >>>> in to split brain with replica 3, which again, is where arbiter would help >>>> gluster resolve it >>>> >>>> I need to amend my previous statement: I was told that arbiter volume >>>> does not store data, only metadata. I cannot find anything in the docs >>>> backing this up however it would make sense for it to be. That being said, >>>> in my setup, I would not include my arbiter or my third node in my ovirt VM >>>> cluster component. I would keep it completely separate >>>> >>>> >>>> On Fri, Sep 1, 2017 at 2:46 PM, Jim Kusznir <jim(a)palousetech.com&gt; >>>> wrote: >>>> >>>>> I'm now also confused as to what the point of an arbiter is / what it >>>>> does / why one would use it. >>>>> >>>>> On Fri, Sep 1, 2017 at 11:44 AM, Jim Kusznir <jim(a)palousetech.com&gt; >>>>> wrote: >>>>> >>>>>> Thanks for the help! >>>>>> >>>>>> Here's my gluster volume info for the data export/brick (I have 3: >>>>>> data, engine, and iso, but they're all configured the same): >>>>>> >>>>>> Volume Name: data >>>>>> Type: Replicate >>>>>> Volume ID: e670c488-ac16-4dd1-8bd3-e43b2e42cc59 >>>>>> Status: Started >>>>>> Snapshot Count: 0 >>>>>> Number of Bricks: 1 x (2 + 1) = 3 >>>>>> Transport-type: tcp >>>>>> Bricks: >>>>>> Brick1: ovirt1.nwfiber.com:/gluster/brick2/data >>>>>> Brick2: ovirt2.nwfiber.com:/gluster/brick2/data >>>>>> Brick3: ovirt3.nwfiber.com:/gluster/brick2/data (arbiter) >>>>>> Options Reconfigured: >>>>>> performance.strict-o-direct: on >>>>>> nfs.disable: on >>>>>> user.cifs: off >>>>>> network.ping-timeout: 30 >>>>>> cluster.shd-max-threads: 8 >>>>>> cluster.shd-wait-qlength: 10000 >>>>>> cluster.locking-scheme: granular >>>>>> cluster.data-self-heal-algorithm: full >>>>>> performance.low-prio-threads: 32 >>>>>> features.shard-block-size: 512MB >>>>>> features.shard: on >>>>>> storage.owner-gid: 36 >>>>>> storage.owner-uid: 36 >>>>>> cluster.server-quorum-type: server >>>>>> cluster.quorum-type: auto >>>>>> network.remote-dio: enable >>>>>> cluster.eager-lock: enable >>>>>> performance.stat-prefetch: off >>>>>> performance.io-cache: off >>>>>> performance.read-ahead: off >>>>>> performance.quick-read: off >>>>>> performance.readdir-ahead: on >>>>>> server.allow-insecure: on >>>>>> [root@ovirt1 ~]# >>>>>> >>>>>> >>>>>> all 3 of my brick nodes ARE also members of the virtualization >>>>>> cluster (including ovirt3). How can I convert it into a full replica >>>>>> instead of just an arbiter? >>>>>> >>>>>> Thanks! >>>>>> --Jim >>>>>> >>>>>> On Fri, Sep 1, 2017 at 9:09 AM, Charles Kozler <ckozleriii(a)gmail.com >>>>>> > wrote: >>>>>> >>>>>>> @Kasturi - Looks good now. Cluster showed down for a moment but >>>>>>> VM's stayed up in their appropriate places. Thanks! >>>>>>> >>>>>>> < Anyone on this list please feel free to correct my response to >>>>>>> Jim if its wrong> >>>>>>> >>>>>>> @ Jim - If you can share your gluster volume info / status I can >>>>>>> confirm (to the best of my knowledge). From my understanding, If you setup >>>>>>> the volume with something like 'gluster volume set <vol> group virt' this >>>>>>> will configure some quorum options as well, Ex: >>>>>>> http://i.imgur.com/Mya4N5o.png >>>>>>> >>>>>>> While, yes, you are configured for arbiter node you're still losing >>>>>>> quorum by dropping from 2 -> 1. You would need 4 node with 1 being arbiter >>>>>>> to configure quorum which is in effect 3 writable nodes and 1 arbiter. If >>>>>>> one gluster node drops, you still have 2 up. Although in this case, you >>>>>>> probably wouldnt need arbiter at all >>>>>>> >>>>>>> If you are configured, you can drop quorum settings and just let >>>>>>> arbiter run since you're not using arbiter node in your VM cluster part (I >>>>>>> believe), just storage cluster part. When using quorum, you need > 50% of >>>>>>> the cluster being up at one time. Since you have 3 nodes with 1 arbiter, >>>>>>> you're actually losing 1/2 which == 50 which == degraded / hindered gluster >>>>>>> >>>>>>> Again, this is to the best of my knowledge based on other quorum >>>>>>> backed software....and this is what I understand from testing with gluster >>>>>>> and ovirt thus far >>>>>>> >>>>>>> On Fri, Sep 1, 2017 at 11:53 AM, Jim Kusznir <jim(a)palousetech.com&gt; >>>>>>> wrote: >>>>>>> >>>>>>>> Huh...Ok., how do I convert the arbitrar to full replica, then? I >>>>>>>> was misinformed when I created this setup. I thought the arbitrator held >>>>>>>> enough metadata that it could validate or refudiate any one replica (kinda >>>>>>>> like the parity drive for a RAID-4 array). I was also under the impression >>>>>>>> that one replica + Arbitrator is enough to keep the array online and >>>>>>>> functional. >>>>>>>> >>>>>>>> --Jim >>>>>>>> >>>>>>>> On Fri, Sep 1, 2017 at 5:22 AM, Charles Kozler < >>>>>>>> ckozleriii(a)gmail.com&gt; wrote: >>>>>>>> >>>>>>>>> @ Jim - you have only two data volumes and lost quorum. >>>>>>>>> Arbitrator only stores metadata, no actual files. So yes, you were running >>>>>>>>> in degraded mode so some operations were hindered. >>>>>>>>> >>>>>>>>> @ Sahina - Yes, this actually worked fine for me once I did that. >>>>>>>>> However, the issue I am still facing, is when I go to create a new gluster >>>>>>>>> storage domain (replica 3, hyperconverged) and I tell it "Host to use" and >>>>>>>>> I select that host. If I fail that host, all VMs halt. I do not recall this >>>>>>>>> in 3.6 or early 4.0. This to me makes it seem like this is "pinning" a node >>>>>>>>> to a volume and vice versa like you could, for instance, for a singular >>>>>>>>> hyperconverged to ex: export a local disk via NFS and then mount it via >>>>>>>>> ovirt domain. But of course, this has its caveats. To that end, I am using >>>>>>>>> gluster replica 3, when configuring it I say "host to use: " node 1, then >>>>>>>>> in the connection details I give it node1:/data. I fail node1, all VMs >>>>>>>>> halt. Did I miss something? >>>>>>>>> >>>>>>>>> On Fri, Sep 1, 2017 at 2:13 AM, Sahina Bose <sabose(a)redhat.com&gt; >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> To the OP question, when you set up a gluster storage domain, >>>>>>>>>> you need to specify backup-volfile-servers=<server2>:<server3> >>>>>>>>>> where server2 and server3 also have bricks running. When server1 is down, >>>>>>>>>> and the volume is mounted again - server2 or server3 are queried to get the >>>>>>>>>> gluster volfiles. >>>>>>>>>> >>>>>>>>>> @Jim, if this does not work, are you using 4.1.5 build with >>>>>>>>>> libgfapi access? If not, please provide the vdsm and gluster mount logs to >>>>>>>>>> analyse >>>>>>>>>> >>>>>>>>>> If VMs go to paused state - this could mean the storage is not >>>>>>>>>> available. You can check "gluster volume status <volname>" to see if >>>>>>>>>> atleast 2 bricks are running. >>>>>>>>>> >>>>>>>>>> On Fri, Sep 1, 2017 at 11:31 AM, Johan Bernhardsson < >>>>>>>>>> johan(a)kafit.se&gt; wrote: >>>>>>>>>> >>>>>>>>>>> If gluster drops in quorum so that it has less votes than it >>>>>>>>>>> should it will stop file operations until quorum is back to normal.If i >>>>>>>>>>> rember it right you need two bricks to write for quorum to be met and that >>>>>>>>>>> the arbiter only is a vote to avoid split brain. >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Basically what you have is a raid5 solution without a spare. >>>>>>>>>>> And when one disk dies it will run in degraded mode. And some raid systems >>>>>>>>>>> will stop the raid until you have removed the disk or forced it to run >>>>>>>>>>> anyway. >>>>>>>>>>> >>>>>>>>>>> You can read up on it here: https://gluster.readthed >>>>>>>>>>> ocs.io/en/latest/Administrator%20Guide/arbiter-volumes-and-q >>>>>>>>>>> uorum/ >>>>>>>>>>> >>>>>>>>>>> /Johan >>>>>>>>>>> >>>>>>>>>>> On Thu, 2017-08-31 at 22:33 -0700, Jim Kusznir wrote: >>>>>>>>>>> >>>>>>>>>>> Hi all: >>>>>>>>>>> >>>>>>>>>>> Sorry to hijack the thread, but I was about to start >>>>>>>>>>> essentially the same thread. >>>>>>>>>>> >>>>>>>>>>> I have a 3 node cluster, all three are hosts and gluster nodes >>>>>>>>>>> (replica 2 + arbitrar). I DO have the mnt_options=backup-volfile-servers= >>>>>>>>>>> set: >>>>>>>>>>> >>>>>>>>>>> storage=192.168.8.11:/engine >>>>>>>>>>> mnt_options=backup-volfile-servers=192.168.8.12:192.168.8.13 >>>>>>>>>>> >>>>>>>>>>> I had an issue today where 192.168.8.11 went down. ALL VMs >>>>>>>>>>> immediately paused, including the engine (all VMs were running on >>>>>>>>>>> host2:192.168.8.12). I couldn't get any gluster stuff working until host1 >>>>>>>>>>> (192.168.8.11) was restored. >>>>>>>>>>> >>>>>>>>>>> What's wrong / what did I miss? >>>>>>>>>>> >>>>>>>>>>> (this was set up "manually" through the article on setting up >>>>>>>>>>> self-hosted gluster cluster back when 4.0 was new..I've upgraded it to 4.1 >>>>>>>>>>> since). >>>>>>>>>>> >>>>>>>>>>> Thanks! >>>>>>>>>>> --Jim >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> On Thu, Aug 31, 2017 at 12:31 PM, Charles Kozler < >>>>>>>>>>> ckozleriii(a)gmail.com&gt; wrote: >>>>>>>>>>> >>>>>>>>>>> Typo..."Set it up and then failed that **HOST**" >>>>>>>>>>> >>>>>>>>>>> And upon that host going down, the storage domain went down. I >>>>>>>>>>> only have hosted storage domain and this new one - is this why the DC went >>>>>>>>>>> down and no SPM could be elected? >>>>>>>>>>> >>>>>>>>>>> I dont recall this working this way in early 4.0 or 3.6 >>>>>>>>>>> >>>>>>>>>>> On Thu, Aug 31, 2017 at 3:30 PM, Charles Kozler < >>>>>>>>>>> ckozleriii(a)gmail.com&gt; wrote: >>>>>>>>>>> >>>>>>>>>>> So I've tested this today and I failed a node. Specifically, I >>>>>>>>>>> setup a glusterfs domain and selected "host to use: node1". Set it up and >>>>>>>>>>> then failed that VM >>>>>>>>>>> >>>>>>>>>>> However, this did not work and the datacenter went down. My >>>>>>>>>>> engine stayed up, however, it seems configuring a domain to pin to a host >>>>>>>>>>> to use will obviously cause it to fail >>>>>>>>>>> >>>>>>>>>>> This seems counter-intuitive to the point of glusterfs or any >>>>>>>>>>> redundant storage. If a single host has to be tied to its function, this >>>>>>>>>>> introduces a single point of failure >>>>>>>>>>> >>>>>>>>>>> Am I missing something obvious? >>>>>>>>>>> >>>>>>>>>>> On Thu, Aug 31, 2017 at 9:43 AM, Kasturi Narra < >>>>>>>>>>> knarra(a)redhat.com&gt; wrote: >>>>>>>>>>> >>>>>>>>>>> yes, right. What you can do is edit the hosted-engine.conf >>>>>>>>>>> file and there is a parameter as shown below [1] and replace h2 and h3 with >>>>>>>>>>> your second and third storage servers. Then you will need to restart >>>>>>>>>>> ovirt-ha-agent and ovirt-ha-broker services in all the nodes . >>>>>>>>>>> >>>>>>>>>>> [1] 'mnt_options=backup-volfile-servers=<h2>:<h3>' >>>>>>>>>>> >>>>>>>>>>> On Thu, Aug 31, 2017 at 5:54 PM, Charles Kozler < >>>>>>>>>>> ckozleriii(a)gmail.com&gt; wrote: >>>>>>>>>>> >>>>>>>>>>> Hi Kasturi - >>>>>>>>>>> >>>>>>>>>>> Thanks for feedback >>>>>>>>>>> >>>>>>>>>>> > If cockpit+gdeploy plugin would be have been used then that >>>>>>>>>>> would have automatically detected glusterfs replica 3 volume created during >>>>>>>>>>> Hosted Engine deployment and this question would not have been asked >>>>>>>>>>> >>>>>>>>>>> Actually, doing hosted-engine --deploy it too also auto detects >>>>>>>>>>> glusterfs. I know glusterfs fuse client has the ability to failover >>>>>>>>>>> between all nodes in cluster, but I am still curious given the fact that I >>>>>>>>>>> see in ovirt config node1:/engine (being node1 I set it to in hosted-engine >>>>>>>>>>> --deploy). So my concern was to ensure and find out exactly how engine >>>>>>>>>>> works when one node goes away and the fuse client moves over to the other >>>>>>>>>>> node in the gluster cluster >>>>>>>>>>> >>>>>>>>>>> But you did somewhat answer my question, the answer seems to be >>>>>>>>>>> no (as default) and I will have to use hosted-engine.conf and change the >>>>>>>>>>> parameter as you list >>>>>>>>>>> >>>>>>>>>>> So I need to do something manual to create HA for engine on >>>>>>>>>>> gluster? Yes? >>>>>>>>>>> >>>>>>>>>>> Thanks so much! >>>>>>>>>>> >>>>>>>>>>> On Thu, Aug 31, 2017 at 3:03 AM, Kasturi Narra < >>>>>>>>>>> knarra(a)redhat.com&gt; wrote: >>>>>>>>>>> >>>>>>>>>>> Hi, >>>>>>>>>>> >>>>>>>>>>> During Hosted Engine setup question about glusterfs volume >>>>>>>>>>> is being asked because you have setup the volumes yourself. If >>>>>>>>>>> cockpit+gdeploy plugin would be have been used then that would have >>>>>>>>>>> automatically detected glusterfs replica 3 volume created during Hosted >>>>>>>>>>> Engine deployment and this question would not have been asked. >>>>>>>>>>> >>>>>>>>>>> During new storage domain creation when glusterfs is >>>>>>>>>>> selected there is a feature called 'use managed gluster volumes' and upon >>>>>>>>>>> checking this all glusterfs volumes managed will be listed and you could >>>>>>>>>>> choose the volume of your choice from the dropdown list. >>>>>>>>>>> >>>>>>>>>>> There is a conf file called /etc/hosted-engine/hosted-engine.conf >>>>>>>>>>> where there is a parameter called backup-volfile-servers="h1:h2" and if one >>>>>>>>>>> of the gluster node goes down engine uses this parameter to provide ha / >>>>>>>>>>> failover. >>>>>>>>>>> >>>>>>>>>>> Hope this helps !! >>>>>>>>>>> >>>>>>>>>>> Thanks >>>>>>>>>>> kasturi >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> On Wed, Aug 30, 2017 at 8:09 PM, Charles Kozler < >>>>>>>>>>> ckozleriii(a)gmail.com&gt; wrote: >>>>>>>>>>> >>>>>>>>>>> Hello - >>>>>>>>>>> >>>>>>>>>>> I have successfully created a hyperconverged hosted engine >>>>>>>>>>> setup consisting of 3 nodes - 2 for VM's and the third purely for storage. >>>>>>>>>>> I manually configured it all, did not use ovirt node or anything. Built the >>>>>>>>>>> gluster volumes myself >>>>>>>>>>> >>>>>>>>>>> However, I noticed that when setting up the hosted engine and >>>>>>>>>>> even when adding a new storage domain with glusterfs type, it still asks >>>>>>>>>>> for hostname:/volumename >>>>>>>>>>> >>>>>>>>>>> This leads me to believe that if that one node goes down (ex: >>>>>>>>>>> node1:/data), then ovirt engine wont be able to communicate with that >>>>>>>>>>> volume because its trying to reach it on node 1 and thus, go down >>>>>>>>>>> >>>>>>>>>>> I know glusterfs fuse client can connect to all nodes to >>>>>>>>>>> provide failover/ha but how does the engine handle this? >>>>>>>>>>> >>>>>>>>>>> _______________________________________________ >>>>>>>>>>> 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 >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> _______________________________________________ >>>>>>>>>>> Users mailing listUsers@ovirt.orghttp://lists.ovirt.org/mailman/listinfo/users >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> _______________________________________________ >>>>>>>>>>> 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 >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>> >>>> >>> >> >