KVM: skip mountpoint check for RBD storage pools

[jeanvetorello]

Description

When using Ceph RBD as primary storage on KVM, the agent currently tries to run:

mountpoint -q /mnt/

This fails because RBD pools are not mounted like NFS or other network filesystems.
As a result, snapshot and template operations fail with errors such as:

libvirt failed to mount storage pool at /mnt/

This patch updates LibvirtStorageAdaptor to skip the mountpoint check when the storage pool type is RBD.
It prevents false errors while keeping the logic unchanged for NFS/NetFS pools.

Types of changes

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

Bug Severity

Major (affects snapshot/template functionality on Ceph RBD)

How Has This Been Tested?

CloudStack 4.21.0.0 + Ceph RBD backend (client.cloudstack user)

Created multiple VM snapshots → successfully registered in Ceph

Created templates from snapshots → completed without mountpoint errors

Verified no regressions on other pool types (NFS untouched)

Checked agent.log: no further mountpoint failures for RBD pools

Related issues

N/A (first-time fix)

[codecov]

Codecov Report

❌ Patch coverage is 60.00000% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 17.39%. Comparing base (f9513b4) to head (945646b).
⚠️ Report is 101 commits behind head on main.

Files with missing lines	Patch %	Lines
.../hypervisor/kvm/storage/LibvirtStorageAdaptor.java	60.00%	4 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #11690      +/-   ##
============================================
+ Coverage     17.36%   17.39%   +0.03%     
- Complexity    15234    15283      +49     
============================================
  Files          5886     5889       +3     
  Lines        525680   526194     +514     
  Branches      64159    64243      +84     
============================================
+ Hits          91261    91544     +283     
- Misses       424120   424304     +184     
- Partials      10299    10346      +47     

Flag	Coverage Δ
uitests	3.62% <ø> (-0.01%)	⬇️
unittests	18.44% <60.00%> (+0.04%)	⬆️

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[DaanHoogland]

@blueorangutan package

[blueorangutan]

@DaanHoogland 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.

[DaanHoogland]

clgtm

[blueorangutan]

Packaging result [SF]: ✔️ el8 ✔️ el9 ✔️ el10 ✔️ debian ✔️ suse15. SL-JID 15124

[harikrishna-patnala]

@blueorangutan test

[blueorangutan]

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

[blueorangutan]

[SF] Trillian test result (tid-14419)
Environment: kvm-ol8 (x2), zone: Advanced Networking with Mgmt server ol8
Total time taken: 51416 seconds
Marvin logs: https://github.com/blueorangutan/acs-prs/releases/download/trillian/pr11690-t14419-kvm-ol8.zip
Smoke tests completed. 146 look OK, 1 have errors, 0 did not run
Only failed and skipped tests results shown below:

Test	Result	Time (s)	Test File
ContextSuite context=TestClusterDRS>:setup	Error	0.00	test_cluster_drs.py

[weizhouapache]

this is called only once by

cloudstack/plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/storage/LibvirtStorageAdaptor.java

Lines 879 to 881 in 4884f52

	if (type == StoragePoolType.NetworkFilesystem) {
	checkNetfsStoragePoolMounted(name);
	}

this PR seems not needed

[weizhouapache]

@jeanvetorello
have you faced any issue in your testing ? any logs ?

[jeanvetorello]

thanks for the help ,
I’m going to open an issue describing the problem in detail, along with the logs, to see if you can help resolve it.

[jeanvetorello]

#11724

[weizhouapache]

thanks @jeanvetorello

did you face the issue #11697 when you test with this patch or not ?

[jeanvetorello]

Thanks for the reviews.
I’ve realized that this PR is not the right fix for the issue.
Skipping the NFS check allowed snapshots to proceed, but it prevents the actual backup to secondary storage, which is required.
Therefore, this is not a valid solution.
The problem is in the way the KVM agent assigns/mounts the pool UUID when handling Ceph + NFS snapshots, and needs to be fixed in another way.
I’ll close this PR and continue investigating the correct approach. Sorry for the noise.