Fix NPE in NASBackupProvider when no running KVM host is available by jmsperu · Pull Request #12680 · apache/cloudstack

jmsperu · 2026-02-21T19:50:58Z

Description

NASBackupProvider.syncBackupStorageStats() crashes with a NullPointerException when ResourceManager.findOneRandomRunningHostByHypervisor() returns null. This happens when no KVM host in the zone has status=Up at the moment the BackupSyncTask runs (e.g., during management server startup, brief agent disconnections, or host state transitions).

The NPE kills the entire BackupSyncTask background job every sync interval (default 300s), flooding the management server log with stack traces and preventing backup storage stats from being updated.

The same pattern exists in deleteBackup() where host can be null when the VM is removed and no running KVM host is available.

Stack Trace

ERROR [o.a.c.b.B.BackupSyncTask] Error trying to run backup-sync background task due to:
[Cannot invoke "com.cloud.host.Host.getId()" because "host" is null].
java.lang.NullPointerException: Cannot invoke "com.cloud.host.Host.getId()" because "host" is null
at org.apache.cloudstack.backup.NASBackupProvider.syncBackupStorageStats(NASBackupProvider.java:544)
at org.apache.cloudstack.backup.BackupManagerImpl$BackupSyncTask.runInContext(BackupManagerImpl.java:1947)

Changes

syncBackupStorageStats(): Add early return with warning log when no running KVM host is found
deleteBackup(): Add null check with descriptive CloudRuntimeException

How Has This Been Tested

Tested on a production CloudStack 4.22.0.0 deployment with 3 KVM hosts and NAS (NFS) backup provider. Before the fix, the NPE fired every 5 minutes after management server restart. After applying the patch, the BackupSyncTask runs cleanly — logging a warning during startup and resuming normally once hosts reconnect.

Types of changes

Bug fix (non-breaking change which fixes an issue)

Screenshot / Video (if applicable)

Before (every 5 minutes):

ERROR [o.a.c.b.B.BackupSyncTask] Error trying to run backup-sync background task due to:
[Cannot invoke "com.cloud.host.Host.getId()" because "host" is null]

After:

WARN [o.a.c.b.NASBackupProvider] Unable to find a running KVM host in zone 1 to sync backup storage stats

ResourceManager.findOneRandomRunningHostByHypervisor() can return null when no KVM host in the zone has status=Up (e.g. during management server startup, brief agent disconnections, or host state transitions). NASBackupProvider.syncBackupStorageStats() and deleteBackup() call host.getId() without a null check, causing a NullPointerException that crashes the entire BackupSyncTask background job every sync interval. This adds null checks in both methods: - syncBackupStorageStats: log a warning and return early - deleteBackup: throw CloudRuntimeException with a descriptive message

boring-cyborg · 2026-02-21T19:51:01Z

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Pull request overview

This PR fixes a NullPointerException in NASBackupProvider that occurs when no running KVM host is available in a zone. The NPE was crashing the BackupSyncTask background job every sync interval and preventing backup storage stats from being updated.

Changes:

Added null check in syncBackupStorageStats() with early return and warning log when no running KVM host is found
Added null check in deleteBackup() with descriptive exception when no running KVM host is available

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Copilot · 2026-02-23T04:36:17Z

+ if (CollectionUtils.isEmpty(repositories)) {
+ return;
+ }


The empty repositories check is placed after the method starts processing but before the host lookup. If repositories are empty, the host lookup at line 573 becomes unnecessary. Consider moving this check before the host lookup, or better yet, to the beginning of the method to avoid any unnecessary operations when there are no repositories to process.

codecov · 2026-02-23T04:42:44Z

Codecov Report

❌ Patch coverage is 0% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 17.92%. Comparing base (30e6c22) to head (80435b4).
⚠️ Report is 23 commits behind head on main.

Files with missing lines	Patch %	Lines
...rg/apache/cloudstack/backup/NASBackupProvider.java	0.00%	4 Missing and 3 partials ⚠️

Additional details and impacted files

@@ Coverage Diff @@## main #12680 +/- ##
============================================
- Coverage 17.92% 17.92% -0.01% 
Complexity 16154 16154 ============================================
Files 5939 5939 Lines 533181 533188 +7 Branches 65237 65240 +3 ============================================
+ Hits 95585 95586 +1 - Misses 426856 426860 +4 - Partials 10740 10742 +2

Flag	Coverage Δ
uitests	`3.67% <ø> (ø)`
unittests	`19.03% <0.00%> (-0.01%)`	⬇️

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DaanHoogland · 2026-02-23T15:10:37Z

@jmsperu , would you want this included in the next 22 release (in which case you might to want to base it of the 4.22 branch)

jmsperu · 2026-02-24T16:58:06Z

@jmsperu , would you want this included in the next 22 release (in which case you might to want to base it of the 4.22 branch)

Hello, am good with int he next release.

DaanHoogland · 2026-02-25T08:46:29Z

@blueorangutan package

blueorangutan · 2026-02-25T08:48:04Z

@DaanHoogland a [SL] Jenkins job has been kicked to build packages. It will be bundled with no SystemVM templates. I'll keep you posted as I make progress.

blueorangutan · 2026-02-25T09:49:52Z

Packaging result [SF]: ✔️ el8 ✔️ el9 ✔️ el10 ✔️ debian ✔️ suse15. SL-JID 16940

DaanHoogland · 2026-02-25T11:40:56Z

@blueorangutan test

blueorangutan · 2026-02-25T11:42:05Z

@DaanHoogland a [SL] Trillian-Jenkins test job (ol8 mgmt + kvm-ol8) has been kicked to run smoke tests

blueorangutan · 2026-02-26T02:39:24Z

[SF] Trillian test result (tid-15525)
Environment: kvm-ol8 (x2), zone: Advanced Networking with Mgmt server ol8
Total time taken: 50963 seconds
Marvin logs: https://github.com/blueorangutan/acs-prs/releases/download/trillian/pr12680-t15525-kvm-ol8.zip
Smoke tests completed. 145 look OK, 5 have errors, 0 did not run
Only failed and skipped tests results shown below:

Test	Result	Time (s)	Test File
test_LoginApiDomain	`Error`	7.70	test_accounts.py
ContextSuite context=TestListIdsParams>:teardown	`Error`	1.15	test_list_ids_parameter.py
test_01_verify_ipv6_network	`Failure`	491.74	test_network_ipv6.py
test_01_snapshot_root_disk	`Error`	5.00	test_snapshots.py
test_02_list_snapshots_with_removed_data_store	`Error`	46.85	test_snapshots.py
test_02_list_snapshots_with_removed_data_store	`Error`	46.85	test_snapshots.py
ContextSuite context=TestSnapshotStandaloneBackup>:teardown	`Error`	27.62	test_snapshots.py
test_01_snapshot_usage	`Error`	28.00	test_usage.py
test_01_vpn_usage	`Error`	1.12	test_usage.py

sureshanaparti

clgtm

sureshanaparti · 2026-02-26T04:23:24Z

Hi @jmsperu Can you re-base with 4.22 branch if this is relavent and can targeted for 4.22.1. Thanks.

weizhouapache · 2026-03-11T14:24:54Z

@abh1sar
can you please review it ?

abh1sar

Code LGTM

abh1sar · 2026-03-12T03:18:16Z

@jmsperu Can you please rebase to 4.22?

jmsperu · 2026-03-12T18:28:16Z

Hello, done.

DaanHoogland · 2026-03-12T18:44:22Z

Hello, done.

hello @jmsperu , what do you mean done? did you rebase or is your issue gone? Is this PR no longer relevant?

jmsperu · 2026-03-12T18:53:50Z

Rebased onto 4.22 and opened a new PR since the original couldn't be reopened after the base branch change: #12805

DaanHoogland · 2026-03-12T18:57:18Z

Rebased onto 4.22 and opened a new PR since the original couldn't be reopened after the base branch change: #12805

ok, thanks, that wouldn’t have been a problem @jmsperu .

boring-cyborgBot added the component:backup label Feb 21, 2026

shwstppr requested a review from Copilot February 23, 2026 04:34

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DaanHoogland linked an issue Feb 23, 2026 that may be closed by this pull request
NullPointerException in NASBackupProvider.syncBackupStorageStats when no KVM host is in "Up" state #12679
Closed

DaanHoogland added this to the 4.23.0 milestone Feb 25, 2026

sureshanaparti approved these changes Feb 26, 2026
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bernardodemarco mentioned this pull request Mar 5, 2026
API key pair restructure #9504
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Pearl1594 mentioned this pull request Mar 10, 2026
Add support to clone existing offerings and update them #12357
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weizhouapache requested a review from abh1sar March 11, 2026 14:25

abh1sar approved these changes Mar 12, 2026
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abh1sar changed the base branch from main to 4.22March 12, 2026 03:17

boring-cyborgBot added component:agent component:api component:build component:integration labels Mar 12, 2026

abh1sar changed the base branch from 4.22 to mainMarch 12, 2026 03:18

Merge branch 'main' into fix/nas-backup-null-host-npe
c60f95e

jmsperu closed this Mar 12, 2026

jmsperu mentioned this pull request Mar 12, 2026
Fix NPE in NASBackupProvider when no running KVM host is available #12805
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jmsperu commented Feb 21, 2026

Description

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Changes

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Types of changes

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