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    xcp-ng server crashed/rebooted due to issues with drbd/linstor?

    Scheduled Pinned Locked Moved XOSTOR
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    • J Offline
      Jonathon @Jonathon
      last edited by Jonathon

      My first idea was to have velero use a different storage class. Something like

      apiVersion: storage.k8s.io/v1
      kind: StorageClass
      metadata:
        name: linstor-ephemeral-retain
      parameters:
        linstor.csi.linbit.com/allowRemoteVolumeAccess: "true"
        linstor.csi.linbit.com/disklessOnRemaining: "true"
        linstor.csi.linbit.com/disklessStoragePool: DfltDisklessStorPool
        linstor.csi.linbit.com/placementCount: "3"
      provisioner: linstor.csi.linbit.com
      **reclaimPolicy: Retain**
      volumeBindingMode: WaitForFirstConsumer
      

      Then have a cronjob collected the Released pvcs every hour. The problem is that can not work, as velero uses the storage class of the backed up pvc. So I would have to change every linstor storage class to Retain, and would effectively disable the automatic garbage collection for the cluster. Which might be fine, but would love to avoid it.

      My second idea is to eliminate the need for the resizing (another work around to hopefully get away from this race condition/bug)
      I am also not seeing any way to modify the storageclass to round up or pad the pv. This would be to attempt to eliminate the need for drbd_bm_resize.
      Currently looking into Kyverno Mutating Webhook to dynamically pad these volumes on the fly to see if that would help me out at all.
      All pvs are already whole numbers of Gi.
      Velero calculates the size of the temporary clone pvc based on the exact byte-count of the used/allocated snapshot metadata, not the #Gi specification of the original pvc.
      Just confirmed with a test
      594a3691-1055-4aa3-a3f4-b35e731390d4-image.jpeg

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      • J Offline
        Jonathon @Jonathon
        last edited by

        I was just moving around the velero backup schedules when it decided to run some again even though it was not time. Crashed xen04 this time. Deleting the possible offending backup schedule until this bug can be identified and fixed.

        Uploaded new bug bundle to nextcloud too.

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        • J Offline
          Jonathon @Jonathon
          last edited by Jonathon

          Logs from xen04 look like they are the same too. Which makes sense.

          20:01:53.805: The Linstor DeviceManager on xen04 triggered an asynchronous alignment for a newly created volume (pvc-fac0a18b-2c23-4fe8-b005-b4f492cec92f), padding it from 26220040 KiB to 26222592 KiB.
          
          20:01:54.034: Simultaneously, an orchestrator (like Velero) began tearing the volume down, shifting the DRBD state to conn( Connected -> TearDown ) and pdsk( Diskless -> DUnknown ).
          
          20:01:58.484: The DRBD worker thread evaluated the shrinking bitmap while the alignment was trying to alter it. This caused the general protection fault: 0000 [#1] SMP NOPTI at instruction RIP: e030:drbd_bm_count_bits+0x223/0x300 [drbd], crashing the kernel.
          
          poddingueP 1 Reply Last reply Reply Quote 0
          • poddingueP Online
            poddingue Vates 🪐 @Jonathon
            last edited by

            That timeline is the clearest version of this yet. xen04 going down the same way as xen05 makes the race look real to me rather than coincidental, unless I am reading the ordering wrong.
            The fault lands inside drbd_bm_count_bits, so in the DRBD module itself, which makes me think this is an upstream LINBIT question as much as an XCP-ng one. I do not know enough about how that module gets packaged here to say who owns the fix though. Might be worth another mention to @Team-Storage so someone can open your bundles with your post #10 next to them.
            On the padding idea I am out of my depth: no idea whether LINSTOR can be told to pre-round a volume at creation, but asking LINBIT directly seems worth a try since it would sidestep drbd_bm_resize entirely. 🤷

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            • M Online
              MajorP93 @poddingue
              last edited by MajorP93

              @jonathon are you using your LINSTOR/DRBD stack in the form of licensed XOSTOR? Your issue looks a case for pro support. Did you consider opening a case with pro support?

              J 1 Reply Last reply Reply Quote 0
              • J Offline
                Jonathon @MajorP93
                last edited by Jonathon

                @MajorP93 No we do not have pro support at the moment

                hmmm. Really seems like a build with 9.2.19 could fix all of this.
                How can I request for a build @poddingue ?

                https://github.com/LINBIT/drbd/blob/drbd-9.2.19/ChangeLog#L61
                9.2.17

                • Fix a kernel crash triggered by a crafted/invalid netlink message

                https://github.com/LINBIT/drbd/blob/drbd-9.2.19/ChangeLog#L24
                9.2.19

                • Fix an AB-BA deadlock between online resize and activity-log transactions
                • Fix several races during connection teardown that could crash or
                  hang (ack_sender requeue, pending ping work, in-progress lb-tcp
                  connect)
                poddingueP 1 Reply Last reply Reply Quote 0
                • poddingueP Online
                  poddingue Vates 🪐 @Jonathon
                  last edited by

                  On the version question, 8.3 ships DRBD 9.2.18 right now (that's what kmod-drbd.spec says on the 8.3 branch), so you'd be asking for a single point bump rather than a big jump.
                  That probably helps you. Of your two links though, I think the netlink crash fix is a 9.2.17 entry, which would mean it's already in what you're running. 🤷
                  The 9.2.19 line that looks closest to your crash to me is the connection-teardown races one rather than the AB-BA deadlock, since a deadlock would hang rather than throw a GPF, but you've read these traces far more closely than I have so correct me if that's backwards.
                  I can't request a build myself, that's a @Team-Storage call rather than mine, though your post #13 timeline next to those changelog lines is a stronger case than most version-bump requests turn up with.

                  J 1 Reply Last reply Reply Quote 0
                  • J Offline
                    Jonathon @poddingue
                    last edited by Jonathon

                    @poddingue I'm fully up to date, but only at version 9.2.16

                    [14:57 ovbh-pprod-xen02 ~]# drbdadm --version
                    DRBDADM_BUILDTAG=GIT-hash:\ 71c8bcff6ea77a022b272a7eba649a774251bac4\ build\ by\ @buildsystem\,\ 2025-11-03\ 10:21:36
                    DRBDADM_API_VERSION=2
                    DRBD_KERNEL_VERSION_CODE=0x090210
                    DRBD_KERNEL_VERSION=9.2.16
                    DRBDADM_VERSION_CODE=0x092100
                    DRBDADM_VERSION=9.33.0
                    [14:57 ovbh-pprod-xen02 ~]# drbd-reactor --version
                    drbd-reactor 1.9.0
                    [14:57 ovbh-pprod-xen02 ~]# 
                    

                    ae60a96f-99c9-4e31-9f74-362d7d4426d7-image.jpeg

                    There are no updates that I can install

                    [14:08 ovbh-pprod-xen02 ~]# yum check-update
                    Loaded plugins: fastestmirror
                    Loading mirror speeds from cached hostfile
                    Excluding mirror: updates.xcp-ng.org
                     * xcp-ng-base: mirrors.xcp-ng.org
                    Excluding mirror: updates.xcp-ng.org
                     * xcp-ng-updates: mirrors.xcp-ng.org
                    zabbix                                                                                                                                                                                                                                 | 3.0 kB  00:00:00     
                    zabbix-non-supported                                                                                                                                                                                                                   | 2.9 kB  00:00:00     
                    zabbix/x86_64/primary_db                                                                                                                                                                                                               | 114 kB  00:00:00     
                    
                    zabbix-agent.x86_64                                                                                                         7.0.28-release1.el7                                                                                                         zabbix
                    
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                    • J Offline
                      Jonathon @Jonathon
                      last edited by

                      For now I have upgraded all hosts to use --enablerepo=xcp-ng-linstor-testing to get kmod-drbd.x86_64 0:9.2.18-2.0.xcpng8.3
                      That way it is there to be picked up if the host crashes again.
                      https://github.com/xcp-ng-rpms/drbd/blob/master/SPECS/kmod-drbd.spec
                      https://koji.xcp-ng.org/buildinfo?buildID=5747

                      [12:15 ovbh-pprod-xen04 ~]# yum upgrade --enablerepo=xcp-ng-linstor-testing
                      Loaded plugins: fastestmirror
                      Loading mirror speeds from cached hostfile
                      Excluding mirror: updates.xcp-ng.org
                       * xcp-ng-base: mirrors.xcp-ng.org
                      Excluding mirror: updates.xcp-ng.org
                       * xcp-ng-updates: mirrors.xcp-ng.org
                      grafana/signature                                                                                                                                                                                                                      |  810 B  00:00:00     
                      grafana/signature                                                                                                                                                                                                                      | 3.0 kB  00:00:00 !!! 
                      xcp-ng-linstor-testing/signature                                                                                                                                                                                                       |  473 B  00:00:00     
                      xcp-ng-linstor-testing/signature                                                                                                                                                                                                       | 3.0 kB  00:00:00 !!! 
                      zabbix                                                                                                                                                                                                                                 | 3.0 kB  00:00:00     
                      zabbix-non-supported                                                                                                                                                                                                                   | 2.9 kB  00:00:00     
                      (1/3): grafana/primary_db                                                                                                                                                                                                              | 879 kB  00:00:00     
                      (2/3): xcp-ng-linstor-testing/primary_db                                                                                                                                                                                               | 2.4 kB  00:00:00     
                      (3/3): zabbix/x86_64/primary_db                                                                                                                                                                                                        | 114 kB  00:00:00     
                      Resolving Dependencies
                      --> Running transaction check
                      ---> Package kmod-drbd.x86_64 0:9.2.16-1.0.xcpng8.3 will be updated
                      ---> Package kmod-drbd.x86_64 0:9.2.18-2.0.xcpng8.3 will be an update
                      ---> Package zabbix-agent.x86_64 0:7.0.27-release1.el7 will be updated
                      ---> Package zabbix-agent.x86_64 0:7.0.28-release1.el7 will be an update
                      --> Finished Dependency Resolution
                      
                      Dependencies Resolved
                      
                      ==============================================================================================================================================================================================================================================================
                       Package                                                    Arch                                                 Version                                                           Repository                                                            Size
                      ==============================================================================================================================================================================================================================================================
                      Updating:
                       kmod-drbd                                                  x86_64                                               9.2.18-2.0.xcpng8.3                                               xcp-ng-linstor-testing                                               2.8 M
                       zabbix-agent                                               x86_64                                               7.0.28-release1.el7                                               zabbix                                                               660 k
                      
                      Transaction Summary
                      ==============================================================================================================================================================================================================================================================
                      Upgrade  2 Packages
                      
                      Total download size: 3.4 M
                      Is this ok [y/d/N]: y
                      Downloading packages:
                      Delta RPMs disabled because /usr/bin/applydeltarpm not installed.
                      (1/2): zabbix-agent-7.0.28-release1.el7.x86_64.rpm                                                                                                                                                                                     | 660 kB  00:00:00     
                      (2/2): kmod-drbd-9.2.18-2.0.xcpng8.3.x86_64.rpm                                                                                                                                                                                        | 2.8 MB  00:00:01     
                      --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                      Total                                                                                                                                                                                                                         2.8 MB/s | 3.4 MB  00:00:01     
                      Running transaction check
                      Running transaction test
                      Transaction test succeeded
                      Running transaction
                        Updating   : kmod-drbd-9.2.18-2.0.xcpng8.3.x86_64                                                                                                                                                                                                       1/4 
                        Updating   : zabbix-agent-7.0.28-release1.el7.x86_64                                                                                                                                                                                                    2/4 
                        Cleanup    : kmod-drbd-9.2.16-1.0.xcpng8.3.x86_64                                                                                                                                                                                                       3/4 
                        Cleanup    : zabbix-agent-7.0.27-release1.el7.x86_64                                                                                                                                                                                                    4/4 
                        Verifying  : zabbix-agent-7.0.28-release1.el7.x86_64                                                                                                                                                                                                    1/4 
                        Verifying  : kmod-drbd-9.2.18-2.0.xcpng8.3.x86_64                                                                                                                                                                                                       2/4 
                        Verifying  : kmod-drbd-9.2.16-1.0.xcpng8.3.x86_64                                                                                                                                                                                                       3/4 
                        Verifying  : zabbix-agent-7.0.27-release1.el7.x86_64                                                                                                                                                                                                    4/4 
                      
                      Updated:
                        kmod-drbd.x86_64 0:9.2.18-2.0.xcpng8.3                                                                                       zabbix-agent.x86_64 0:7.0.28-release1.el7                                                                                      
                      
                      Complete!
                      
                      poddingueP 1 Reply Last reply Reply Quote 0
                      • poddingueP Online
                        poddingue Vates 🪐 @Jonathon
                        last edited by poddingue

                        Oopsie, I was wrong.
                        I owe you a correction on the version, and that one is on me. I said 8.3 ships 9.2.18, but I was reading the spec file on the branch rather than what you actually get from the stable repo. 🤷
                        Your yum check-update output answers it better than I did: stable leaves you on 9.2.16, and 9.2.18 only turns up once xcp-ng-linstor-testing is enabled.

                        The screenshot in that same post is the part the still puzzles me. XO says "All good, patches up to date" while the module underneath is two point releases back, which I assume is what everyone else running XOSTOR sees too. If the connection-teardown fixes you found really are in 9.2.19, that is three releases of distance on the exact code path your traces land in, not the single bump I described.

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