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Posted to commits@cloudstack.apache.org by "jmsperu (via GitHub)" <gi...@apache.org> on 2026/02/21 19:46:45 UTC
[I] NullPointerException in NASBackupProvider.syncBackupStorageStats when no KVM host is in "Up" state [cloudstack]
jmsperu opened a new issue, #12679:
URL: https://github.com/apache/cloudstack/issues/12679
### problem
`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 exact 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.
## 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)
## Affected Code
File: plugins/backup/nas/src/main/java/org/apache/cloudstack/backup/NASBackupProvider.java`
java
@Override
public void syncBackupStorageStats(Long zoneId) {
final List<BackupRepository> repositories = backupRepositoryDao.listByZoneAndProvider(zoneId, getName());
final Host host = resourceManager.findOneRandomRunningHostByHypervisor(Hypervisor.HypervisorType.KVM, zoneId);
// host can be null here, but no null check before using it:
for (final BackupRepository repository : repositories) {
...
answer = (BackupStorageStatsAnswer) agentManager.send(host.getId(), command); // NPE
...
}
}
findOneRandomRunningHostByHypervisor in ResourceManagerImpl returns null when no matching host is found:
if (CollectionUtils.isEmpty(hosts)) {
return null;
}
The same pattern also exists in deleteBackup() (line ~450) where the host can be null when the VM is removed and no running KVM host is available.
Suggested Fix
Add a null check after findOneRandomRunningHostByHypervisor, log a warning, and return early:
@Override
public void syncBackupStorageStats(Long zoneId) {
final List<BackupRepository> repositories = backupRepositoryDao.listByZoneAndProvider(zoneId, getName());
if (repositories.isEmpty()) {
return;
}
final Host host = resourceManager.findOneRandomRunningHostByHypervisor(Hypervisor.HypervisorType.KVM, zoneId);
if (host == null) {
logger.warn("Unable to find a running KVM host in zone {} to sync backup storage stats", zoneId);
return;
}
for (final BackupRepository repository : repositories) {
...
}
}
And similarly for deleteBackup():
Host host = vm != null ? getVMHypervisorHost(vm) :
resourceManager.findOneRandomRunningHostByHypervisor(HypervisorType.KVM, Long.valueOf(backup.getZoneId()));
if (host == null) {
throw new CloudRuntimeException("Unable to find a running KVM host to process backup deletion");
}
Environment
- CloudStack version: 4.22.0.0
- Hypervisor: KVM
- Backup provider: NAS (NFS)
- OS: Ubuntu 24.04, Java 21
How to Reproduce
1. Configure NAS backup provider with an NFS backup repository
2. Assign backup offerings to VMs
3. Restart cloudstack-management (or wait for a transient host disconnect)
4. Observe management-server.log — the NPE fires every backup.framework.sync.interval seconds
Impact
- BackupSyncTask fails completely on every cycle, backup storage capacity stats are never updated
- Log spam (one full stack trace every 5 minutes)
- No data loss, but backup monitoring/reporting is degraded
### versions
The versions of ACS, hypervisors, storage, network etc..
### The steps to reproduce the bug
1.
2.
3.
...
### What to do about it?
_No response_
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Re: [I] NullPointerException in NASBackupProvider.syncBackupStorageStats when no KVM host is in "Up" state [cloudstack]
Posted by "boring-cyborg[bot] (via GitHub)" <gi...@apache.org>.
boring-cyborg[bot] commented on issue #12679:
URL: https://github.com/apache/cloudstack/issues/12679#issuecomment-3939317210
Thanks for opening your first issue here! Be sure to follow the issue template!
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Re: [I] NullPointerException in NASBackupProvider.syncBackupStorageStats when no KVM host is in "Up" state [cloudstack]
Posted by "DaanHoogland (via GitHub)" <gi...@apache.org>.
DaanHoogland commented on issue #12679:
URL: https://github.com/apache/cloudstack/issues/12679#issuecomment-3944834611
thanks @jmsperu , for your extensive analysis. Should be an easy fix. @abh1sar can we just abandon after logging, or should an extra error message/event/alert be created?
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Re: [I] NullPointerException in NASBackupProvider.syncBackupStorageStats when no KVM host is in "Up" state [cloudstack]
Posted by "abh1sar (via GitHub)" <gi...@apache.org>.
abh1sar closed issue #12679: NullPointerException in NASBackupProvider.syncBackupStorageStats when no KVM host is in "Up" state
URL: https://github.com/apache/cloudstack/issues/12679
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Re: [I] NullPointerException in NASBackupProvider.syncBackupStorageStats when no KVM host is in "Up" state [cloudstack]
Posted by "abh1sar (via GitHub)" <gi...@apache.org>.
abh1sar commented on issue #12679:
URL: https://github.com/apache/cloudstack/issues/12679#issuecomment-4197814619
Fixed by https://github.com/apache/cloudstack/pull/12805
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