Snapshots copy from Linstor to NFS fail

ISSUE TYPE

• Bug Report

COMPONENT NAME

Storage - Linstor snapshot

CLOUDSTACK VERSION

4.22.1.0

CONFIGURATION

N/A

OS / ENVIRONMENT

• Cloudstack 4.22.1.0
• Hypervisor KVM
• AlmaLinux 9.8
• Primary storage: Linstor (LVM-thin)
• Secondary storage: NFS

SUMMARY

createSnapshot on any volume backed by a Linstor primary storage pool fails 100% of the time with: Failed to create Snapshot due to an internal error creating Snapshot for volume <volume-uuid>.

The failure is deterministic and reproducible on every attempt, regardless of volume, VM, or snapshot name.

First the snapshot is created succesfully on the Linstor backend, but then the copy to NFS (secundairy storage) fails as CloudStack's KVM agent invokes qemu-img convert against a /dev/mapper/... device path that does not match the path the kernel actually created.

Actual device location: /dev/mapper/linstor_pool-lv--thin-cs--12fc4055--3985--4025--8eb5--d6fd53effe37_00000
Path CloudStack looks for: /dev/mapper/linstor_pool-lvm-thin-cs--12fc4055--3985--4025--8eb5--d6fd53effe37_00000_cs--d7aea646--5f40--46a2--b9dc--77e41ea29336

Notice the missing dashes in the linstor_pool-lv--thin-cs-name.

STEPS TO REPRODUCE

Create disk snapshot on a Linstor volume with NFS as secundairy storage and observe the error message.

EXPECTED RESULTS

Snapshot is created on the Linstor backend and successfully copied to secondary (NFS) storage.

ACTUAL RESULTS

The error logged in management-server.log:

ERROR [o.a.c.a.c.u.s.CreateSnapshotCmd] Failed to create Snapshot due to an internal error creating Snapshot for volume 12fc4055-3985-4025-8eb5-d6fd53effe37 java.lang.RuntimeException: Unexpected exception
	at com.cloud.storage.VolumeApiServiceImpl.takeSnapshotInternal(VolumeApiServiceImpl.java:3999)
	at com.cloud.storage.VolumeApiServiceImpl.takeSnapshot(VolumeApiServiceImpl.java:3910)
	...
Caused by: com.cloud.utils.exception.CloudRuntimeException: Exception: org.apache.cloudstack.utils.qemu.QemuImgException
Message: qemu-img: Could not open '/dev/mapper/linstor_pool-lvm-thin-cs--12fc4055--3985--4025--8eb5--d6fd53effe37_00000_cs--d7aea646--5f40--46a2--b9dc--77e41ea29336': Could not open '/dev/mapper/linstor_pool-lvm-thin-cs--12fc4055--3985--4025--8eb5--d6fd53effe37_00000_cs--d7aea646--5f40--46a2--b9dc--77e41ea29336': No such file or directory
Stack: org.apache.cloudstack.utils.qemu.QemuImgException: ...
	at org.apache.cloudstack.utils.qemu.QemuImg.convert(QemuImg.java:495)
	...
	at com.cloud.hypervisor.kvm.resource.wrapper.LinstorBackupSnapshotCommandWrapper.convertImageToQCow2(LinstorBackupSnapshotCommandWrapper.java:99)
	at com.cloud.hypervisor.kvm.resource.wrapper.LinstorBackupSnapshotCommandWrapper.execute(LinstorBackupSnapshotCommandWrapper.java:156)
	...

	at org.apache.cloudstack.storage.snapshot.SnapshotServiceImpl.backupSnapshot(SnapshotServiceImpl.java:475)
	at org.apache.cloudstack.storage.snapshot.DefaultSnapshotStrategy.backupSnapshot(DefaultSnapshotStrategy.java:204)
	at com.cloud.storage.snapshot.SnapshotManagerImpl.backupSnapshotToSecondary(SnapshotManagerImpl.java:1787)
	at com.cloud.storage.snapshot.SnapshotManagerImpl.takeSnapshot(SnapshotManagerImpl.java:1660)
	...

Suggested fix: apply LVM's standard dash-doubling escape to the volume-group name the same way it's already correctly applied to the cs--<uuid> logical-volume/snapshot name portion.