amitmvyas opened a new issue, #13825:
URL: https://github.com/apache/cloudstack/issues/13825
## Bug: `CreateSharedFileSystem` throws NPE ("template is null") when a zone
has more than one hypervisor type
**Component:**
`plugins/storage/sharedfs/storagevm/src/main/java/org/apache/cloudstack/storage/sharedfs/lifecycle/StorageVmSharedFSLifeCycle.java`
**Affected versions:** 4.22.1.0 (confirmed present on `main` as of
2026-08-06 — same code, unrelated to the two unrelated API-signature diffs
between `main` and `4.22.1.0` in this file)
### Summary
`createSharedFileSystem` fails immediately with:
```
java.lang.NullPointerException: Cannot invoke
"com.cloud.storage.VMTemplateVO.getId()" because "template" is null
```
on any zone that has **more than one hypervisor type**, where at least one
of those hypervisor types has no system VM template available (e.g. an
`External`/MaaS cluster alongside a `KVM` cluster in the same zone).
### Root cause
In `deploySharedFSVM()`:
```java
List<Hypervisor.HypervisorType> hypervisors =
resourceMgr.getSupportedHypervisorTypes(zoneId, false, null);
if (hypervisors.size() > 0) {
Collections.shuffle(hypervisors);
} ...
for (final Iterator<Hypervisor.HypervisorType> iter =
hypervisors.iterator(); iter.hasNext();) {
final Hypervisor.HypervisorType hypervisor = iter.next();
VMTemplateVO template = templateDao.findSystemVMReadyTemplate(zoneId,
hypervisor, preferredArchitecture);
if (template == null && !iter.hasNext()) {
throw new CloudRuntimeException(...);
}
LaunchPermissionVO existingPermission =
launchPermissionDao.findByTemplateAndAccount(template.getId(), owner.getId());
...
```
The hypervisor list is **shuffled**, and the null-check only throws when the
*current* hypervisor is the *last* one in the iteration (`!iter.hasNext()`). If
`template` is `null` for a hypervisor that is **not** last in the (randomized)
order — e.g. `External`, which has no CloudStack system VM template by design —
the code falls through to `template.getId()` on the same iteration instead of
`continue`-ing to the next hypervisor. This crashes before ever reaching a
hypervisor (e.g. `KVM`) that does have a valid, `Ready` system VM template.
Because the list is shuffled, this is intermittent: the call succeeds
whenever the working hypervisor happens to be drawn first, and fails whenever a
hypervisor with no system VM template is drawn first with more entries still
pending.
### Reproduction
1. Zone with two clusters of different hypervisor types, one of which has no
system VM template registered (e.g. `KVM` + `External`/MaaS).
2. Call `createSharedFileSystem` repeatedly.
3. Observe intermittent NPE vs. success depending on shuffle order, even
though the working hypervisor's system VM template is verified `Active` /
`Ready` / fully downloaded in the DB (`vm_template`, `template_zone_ref`,
`template_store_ref`).
### Fix
Only throw once every hypervisor candidate has been exhausted; otherwise
skip to the next one:
```java
VMTemplateVO template = templateDao.findSystemVMReadyTemplate(zoneId,
hypervisor, preferredArchitecture);
if (template == null) {
if (!iter.hasNext()) {
throw new CloudRuntimeException(String.format("Unable to find the
systemvm template for %s or it was not downloaded in %s.",
hypervisor.toString(), zone.toString()));
}
continue;
}
LaunchPermissionVO existingPermission =
launchPermissionDao.findByTemplateAndAccount(template.getId(), owner.getId());
```
Patch attached: `sharedfs-template-null-npe.patch` (applies cleanly to
`4.22.1.0` via `git apply` or `patch -p1` from the repo root).
### Impact
Any deployment mixing hypervisor types within one zone (common with hybrid
KVM + MaaS/External or KVM + VMware setups) can hit this nondeterministically
for every Shared FileSystem creation attempt, with no workaround short of
isolating hypervisor types into separate zones.
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