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    Detached VM Snapshots after Warm Migration

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    • DustyArmstrongD Offline
      DustyArmstrong
      last edited by

      I recently migrated all my VMs to new hosts in a new pool via warm migration, which worked great, but I am now seeing "detached snapshots" for the VMs that I moved. I have tested on another VM which was created natively on one of the new hosts and it does not have the same problem.

      It says it has a "Missing VM":

      ff5b9719-c951-4ceb-8b02-048737513911-image.png

      I also recently migrated from a Xen Orchestra container to another (x86 -> ARM), but unsure if that has anything to do with it - I restored my XO config from a metadata backup. The natively created VM was made after this move.

      Is there something I need to do or re-configure to prevent this? The snapshots appear to work, but I have not yet tried to revert to one.

      DustyArmstrongD 1 Reply Last reply Reply Quote 0
      • DustyArmstrongD Offline
        DustyArmstrong @DustyArmstrong
        last edited by DustyArmstrong

        Looked at some other posts, it seems it probably does have something to do with my old XO. This is no longer active, can I re-associate the VMs with my current XO instance? I imported my config from a backup, so I thought that would cover it, my new XO instance spun up exactly like the old one.

        Broken snapshot (logs show it initiated from the pool master's IP):

        5505 HTTPS 123.456.789.2->:::80|Async.VM.snapshot

        ALLOWED' 'OK' 'API' 'VM.snapshot' (('vm' '' '' 'OpaqueRef:cce8c856-3310-a551-7cf3-f3ec6d68903d')

        Working snapshot (logs show it initiated from my XO's IP):

        62327 HTTPS 123.456.789.6->|Async.VM.snapshot

        ALLOWED' 'OK' 'API' 'VM.snapshot' (('vm' 'CCTV' 'cd95df02-a907-bdaa-2c0e-ca503656460b' 'OpaqueRef:00c31a47-69d9-753d-5481-d5a10e881e13')

        So it seems that the broken VMs are being initiated from the host they run on, not XO.

        DustyArmstrongD 1 Reply Last reply Reply Quote 0
        • DustyArmstrongD Offline
          DustyArmstrong @DustyArmstrong
          last edited by

          OK, I still had my old pool master registered as a server in XO (disabled), removing this and restarting XO now shows the VMs properly in the audit logs when snapshot, and it shows them being initiated by my XO IP, but the snapshots are still seen as detached ("Missing VM").

          Maybe it will just resolve itself eventually if XAPI is holding onto stale references? I still have my old backups ("Detached backups") that I'm waiting to remove (job itself removed), maybe that's also impacting things - I will be removing the backed up VHDs once my NAS has copied them to an external drive (very slow!).

          I'm not opposed to blowing XO away and starting it over, I need to start a new backup job anyway - if there's a procedure/best practice to go by in order to re-create all the metadata I'd be interested.

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          • P Online
            Pilow @DustyArmstrong
            last edited by

            @DustyArmstrong I have a corner case where I see these detached snapshots, related to backup.

            I have a (remote) pool, the master is attached by a XOproxy on main XOA.
            All snapshots done by remote XOA are seen as "detached" snapshots on the main XOA where the pool is a distant one.

            Main XOA do not own backup jobs, so it is not aware of the snapshots, so mark them as detached.

            I think this is your current situation, you have 2 XO servers, one doing snapshots, the other seeing them as detached.

            DustyArmstrongD 1 Reply Last reply Reply Quote 0
            • DustyArmstrongD Offline
              DustyArmstrong @Pilow
              last edited by

              @Pilow Thanks for your reply.

              I only have 1 XO currently, the other old one is offline - they're both on the same physical box, just a different Docker container. The old XO is currently downed and has been for a while, it never interacted with this new pool I made either. I downed it, restored my XO config to the new XO, which all worked fine. Steps were:

              1. Down old XO
              2. Up new XO and restore XO config (same IP), all good
              3. Install XCP on new hosts (hardware refresh)
              4. Create pool from new hosts on new XO
              5. Warm migrate VMs from old hosts to new hosts, all good

              My old XO server hasn't interacted with any of this, it can't, it would cause a clash by using the same ports. I haven't checked yet today, but I'm hoping it just kind of resolves itself now the audit logs are showing the correct VM info. I feel like it's just a sticky frontend cache of some sort.

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              • P Online
                Pilow @DustyArmstrong
                last edited by

                @DustyArmstrong ho okay, so old XO is downed.

                You could have 2 XO connected to the same pools, as long as they do not have same IP address.

                beware, I do not tell you to do that, it is not best practice at all if you ever are in this situation, you must understand what could happen (detached snaps, licence problems, ...)

                but I thought this was the case

                in your case, did you do snaps/backups BEFORE reverting the XO config of old XO to new XO ?
                as far as I understand, this could have get you detached snapshots (snapshots being on VMs but not initiated by the restored version of your current online XO)

                or do I overthink this too much ?!

                keep us informed if you manage to clear the situation, curious about it

                DustyArmstrongD 1 Reply Last reply Reply Quote 0
                • DustyArmstrongD Offline
                  DustyArmstrong @Pilow
                  last edited by

                  @Pilow They would have the same IP address, the new XO is just a new Docker container on the same physical host but with a new database (different version of Redis on ARM so couldn't like-for-like re-use). There is only 1 XO running, 100% certain. The snapshots in the audit log now reflect XO as having initiated them, where before it was the host itself (fallback) - this may all be magically resolved now, but I'm not home to look yet.

                  No, I made a backup of all my VMs before the warm migration, but the backup was made on the new XO instance, successfully, backing up the VMs on the old hosts (XCP1 & XCP2).

                  So the full process I took was:

                  1. 2 weeks ago, downed old XO
                  2. Brought up brand new XO (fresh Redis DB), imported config, all working
                  3. This weekend, spun up 2 new XCP hosts (lot of drama but we will ignore that) XC1 & XC2
                  4. Created new pool containing the new XCP hosts (XC1 & XC2)
                  5. Initiated a backup of all VMs on old host pool (XCP1 & XCP2) using an existing scheduled backup - manually triggered - backup succeeds
                  6. Warm migrate VMs from pool XCP1/XCP2 to XC1/XC2 - success
                  7. Disable old host pool XCP1/XCP2, VMs working as expected
                  8. Snapshot a warm migrated VM - detached snapshot - snapshotting a VM created natively on XC1/XC2 does not have this issue
                  9. Removed old pool XCP1/XCP2 entirely from XO - this solved the audit logs side of things (I think this is XAPI)
                  10. Logs now show VM info correctly, but frontend still displays a detached snapshot

                  My guess is that it may think the snapshots were happening on the old pool/old VM, not the warm migrated copy, or something like that.

                  I will update the thread if I manage to resolve everything, I'll keep an eye out anyway in case someone from Vates knows any more on this!

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