Fix rollback disk snapshots on instance snapshot failure by sureshanaparti · Pull Request #12949 · apache/cloudstack

sureshanaparti · 2026-04-02T05:13:37Z

Description

This PR fixes rollback disk snapshots on instance snapshot failure.

Fixes #12927

Types of changes

Breaking change (fix or feature that would cause existing functionality to change)
New feature (non-breaking change which adds functionality)
Bug fix (non-breaking change which fixes an issue)
Enhancement (improves an existing feature and functionality)
Cleanup (Code refactoring and cleanup, that may add test cases)
Build/CI
Test (unit or integration test code)

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sureshanaparti · 2026-04-02T05:16:27Z

@blueorangutan package

blueorangutan · 2026-04-02T05:18:04Z

@sureshanaparti a [SL] Jenkins job has been kicked to build packages. It will be bundled with KVM, XenServer and VMware SystemVM templates. I'll keep you posted as I make progress.

codecov · 2026-04-02T05:22:54Z

Codecov Report

❌ Patch coverage is 20.00000% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 17.60%. Comparing base (4708121) to head (db0ea04).

Files with missing lines	Patch %	Lines
.../storage/vmsnapshot/StorageVMSnapshotStrategy.java	20.00%	8 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               4.22   #12949      +/-   ##
============================================
- Coverage     17.60%   17.60%   -0.01%     
+ Complexity    15677    15676       -1     
============================================
  Files          5918     5918              
  Lines        531681   531685       +4     
  Branches      65005    65006       +1     
============================================
- Hits          93623    93616       -7     
- Misses       427498   427509      +11     
  Partials      10560    10560

Flag	Coverage Δ
uitests	`3.70% <ø> (ø)`
unittests	`18.67% <20.00%> (-0.01%)`	⬇️

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blueorangutan · 2026-04-02T06:22:02Z

Packaging result [SF]: ✔️ el8 ✔️ el9 ✔️ el10 ✔️ debian ✔️ suse15. SL-JID 17339

Copilot

Pull request overview

Fixes cleanup/rollback of per-volume disk snapshots when an instance (VM) snapshot operation fails, preventing orphaned snapshots and incorrect snapshot resource counts (issue #12927).

Changes:

Track created disk snapshots for rollback using a Map<volumeId, SnapshotInfo> to ensure snapshots are rolled back even if creation fails mid-way.
Harden rollback logic with null checks and improve rollback logging.
Update the KVM VM snapshot strategy unit test to match the new createDiskSnapshot method signature.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
engine/storage/snapshot/src/main/java/org/apache/cloudstack/storage/vmsnapshot/StorageVMSnapshotStrategy.java	Track snapshots for rollback via volume-id map; ensure rollback attempts occur on failures; add null-safety/logging improvements.
engine/storage/snapshot/src/test/java/org/apache/cloudstack/storage/vmsnapshot/VMSnapshotStrategyKVMTest.java	Adjust unit test to pass the new rollback map parameter to `createDiskSnapshot`.

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Copilot · 2026-04-02T08:43:56Z

...apshot/src/main/java/org/apache/cloudstack/storage/vmsnapshot/StorageVMSnapshotStrategy.java

@@ -456,7 +464,7 @@ protected SnapshotInfo createDiskSnapshot(VMSnapshot vmSnapshot, List<SnapshotIn
        if (snapshotInfo == null) {
            throw new CloudRuntimeException("Failed to create snapshot");
        } else {


volumeToSnapshotInfoMapForRollback.put(vol.getId(), snapshotInfo) is performed twice (before and after takeSnapshot). If the intent is to ensure rollback coverage when takeSnapshot throws, keep the pre-takeSnapshot put, but drop the else block and only overwrite the map entry if takeSnapshot returns a different SnapshotInfo instance. This removes redundant writes and makes the intent clearer.

Suggested change

} else {

}

if (snapshotInfo != volumeToSnapshotInfoMapForRollback.get(vol.getId())) {

Copilot · 2026-04-02T08:43:57Z

...apshot/src/main/java/org/apache/cloudstack/storage/vmsnapshot/StorageVMSnapshotStrategy.java

@@ -448,6 +455,7 @@ protected SnapshotInfo createDiskSnapshot(VMSnapshot vmSnapshot, List<SnapshotIn
        vol.addPayload(setPayload(vol, snapshot, quiescevm));
        SnapshotInfo snapshotInfo = snapshotDataFactory.getSnapshot(snapshot.getId(), vol.getDataStore());
        snapshotInfo.addPayload(vol.getpayload());
+        volumeToSnapshotInfoMapForRollback.put(vol.getId(), snapshotInfo);
        SnapshotStrategy snapshotStrategy = storageStrategyFactory.getSnapshotStrategy(snapshotInfo, SnapshotOperation.TAKE);
        if (snapshotStrategy == null) {
            throw new CloudRuntimeException("Could not find strategy for snapshot uuid:" + snapshotInfo.getUuid());
@@ -456,7 +464,7 @@ protected SnapshotInfo createDiskSnapshot(VMSnapshot vmSnapshot, List<SnapshotIn
        if (snapshotInfo == null) {
            throw new CloudRuntimeException("Failed to create snapshot");
        } else {


The new rollback behavior relies on adding the snapshot to the rollback map before snapshotStrategy.takeSnapshot(...) runs so that failures/exceptions still get cleaned up. There’s no unit test covering the failure path (e.g., takeSnapshot throws/returns null) and verifying that rollback deletes the persisted snapshot record. Please add a test for this scenario to prevent regressions of #12927.

DaanHoogland

I may be missing some context, hence my questions?!?

DaanHoogland · 2026-04-02T13:43:00Z

...apshot/src/main/java/org/apache/cloudstack/storage/vmsnapshot/StorageVMSnapshotStrategy.java

        vol.addPayload(setPayload(vol, snapshot, quiescevm));
        SnapshotInfo snapshotInfo = snapshotDataFactory.getSnapshot(snapshot.getId(), vol.getDataStore());
        snapshotInfo.addPayload(vol.getpayload());
+        volumeToSnapshotInfoMapForRollback.put(vol.getId(), snapshotInfo);


so it might be added twice right? so why the else at line 466?

The else is so we have the updated snapshot info to delete. Although, I'm not familiar enough with this code to say that it makes a difference. Anyway, if it does make a difference, I would just remove the else to reduce indentation; if it does not make a difference, I would only add the info once on the hashmap.

DaanHoogland · 2026-04-02T13:44:25Z

...apshot/src/main/java/org/apache/cloudstack/storage/vmsnapshot/StorageVMSnapshotStrategy.java

            }
            if (!result) {
-                for (SnapshotInfo snapshotInfo : forRollback) {
+                for (SnapshotInfo snapshotInfo : volumeToSnapshotInfoMapForRollback.values()) {


this seems the only usage, why not a HashSet?

the snapshot info object after take snapshot can be new/updated one, which will be considered during rollback. with HashSet, chances that another snapshot object for the same volume is added if it's new.

@DaanHoogland I updated it, back to List

sureshanaparti · 2026-04-07T07:12:06Z

@blueorangutan package

blueorangutan · 2026-04-07T07:14:05Z

@sureshanaparti a [SL] Jenkins job has been kicked to build packages. It will be bundled with KVM, XenServer and VMware SystemVM templates. I'll keep you posted as I make progress.

blueorangutan · 2026-04-07T08:09:48Z

Packaging result [SF]: ✔️ el8 ✔️ el9 ✔️ el10 ✔️ debian ✔️ suse15. SL-JID 17383

JoaoJandre

CLGTM, did not test it

Fix rollback disk snapshots on instance snapshot failure

bd1ca29

boring-cyborg bot added the component:storage label Apr 2, 2026

sureshanaparti mentioned this pull request Apr 2, 2026

snapshot resourcecount not updated when deleting a failed VM snapshot #12927

Open

sureshanaparti linked an issue Apr 2, 2026 that may be closed by this pull request

snapshot resourcecount not updated when deleting a failed VM snapshot #12927

Open

sureshanaparti added this to the 4.22.1 milestone Apr 2, 2026

sureshanaparti added this to Apache CloudStack 4.22.1 Apr 2, 2026

github-project-automation bot moved this to Todo in Apache CloudStack 4.22.1 Apr 2, 2026

sureshanaparti moved this from Todo to In Progress in Apache CloudStack 4.22.1 Apr 2, 2026

sureshanaparti added the status:needs-testing label Apr 2, 2026

sureshanaparti requested review from DaanHoogland, JoaoJandre, Copilot and slavkap April 2, 2026 08:39

Copilot started reviewing on behalf of sureshanaparti April 2, 2026 08:40 View session

Copilot AI reviewed Apr 2, 2026

View reviewed changes

DaanHoogland reviewed Apr 2, 2026

View reviewed changes

use list, and add snapshot info prior to take snapshot

db0ea04

JoaoJandre approved these changes Apr 7, 2026

View reviewed changes

	} else {
	}
	if (snapshotInfo != volumeToSnapshotInfoMapForRollback.get(vol.getId())) {

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Description

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sureshanaparti commented Apr 2, 2026 •

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