Multiple CD-ROM / ISO Support Per VM

[Damans227]

Description

Adds multiple CD-ROM support per VM on KVM. Today CloudStack allows only one ISO per VM, forcing a manual ISO-swap workflow to install Windows on KVM (Windows installer + VirtIO drivers). After this PR each VM can hold up to vm.cdrom.max.count ISOs simultaneously, each appearing as its own CD-ROM inside the guest.

What changes:

• detachIso takes an optional id (required when multiple ISOs are attached).
• listVirtualMachines returns isos[]; legacy isoid still reflects the bootable ISO.
• New global config vm.cdrom.max.count (default 1), clamped by the hypervisor cap (KVM/IDE = 2).
• New vm_iso_map table holds extra slots; user_vm.iso_id is kept as the bootable pointer for back-compat.

Scope: KVM only.

Design doc: https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=421957739

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)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

Screenshots (if appropriate):

Screen.Recording.2026-05-04.at.5.20.18.PM.mov

How Has This Been Tested?

• End-to-end on a KVM lab across cap=1/2/5, plus the UI manually.
• Unit tests added in TemplateManagerImplTest for slot allocation, the duplicate-attach check, and the detach-id resolution helper.

How did you try to break this feature and the system with this change?

• Set the global cap both lower and higher than the hypervisor's actual capacity to confirm clamping
• Tried to re-attach an already-attached ISO
• Detached the bootable and non-bootable ISO in turn to confirm user_vm.iso_id and vm_iso_map stay in sync
• Stopped and restarted a multi-ISO VM to confirm boot-time persistence
• Confirmed legacy single-ISO API consumers (isoid in listVirtualMachines) see no functional change

[codecov]

Codecov Report

❌ Patch coverage is 20.98765% with 192 lines in your changes missing coverage. Please review.
✅ Project coverage is 18.08%. Comparing base (1e512ab) to head (61396a1).

Files with missing lines	Patch %	Lines
...n/java/com/cloud/template/TemplateManagerImpl.java	27.20%	91 Missing and 8 partials ⚠️
...rc/main/java/com/cloud/vm/dao/VmIsoMapDaoImpl.java	0.00%	36 Missing ⚠️
...e/cloudstack/api/response/AttachedIsoResponse.java	0.00%	21 Missing ⚠️
.../schema/src/main/java/com/cloud/vm/VmIsoMapVO.java	37.50%	15 Missing ⚠️
...ava/com/cloud/api/query/dao/UserVmJoinDaoImpl.java	18.18%	7 Missing and 2 partials ⚠️
...ud/hypervisor/kvm/storage/KVMStorageProcessor.java	0.00%	7 Missing ⚠️
...apache/cloudstack/api/response/UserVmResponse.java	33.33%	4 Missing ⚠️
.../cloudstack/api/command/user/iso/DetachIsoCmd.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #13101      +/-   ##
============================================
- Coverage     18.08%   18.08%   -0.01%     
- Complexity    16706    16722      +16     
============================================
  Files          6037     6041       +4     
  Lines        542437   542707     +270     
  Branches      66420    66471      +51     
============================================
+ Hits          98088    98126      +38     
- Misses       433333   433554     +221     
- Partials      11016    11027      +11     

Flag	Coverage Δ
uitests	3.52% <ø> (+<0.01%)	⬆️
unittests	19.24% <20.98%> (-0.01%)	⬇️

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[Damans227]

@blueorangutan package

[blueorangutan]

@Damans227 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]

Packaging result [SF]: ✖️ el8 ✖️ el9 ✖️ debian ✖️ suse15. SL-JID 17708

[Damans227]

@blueorangutan package

[blueorangutan]

@Damans227 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]

Packaging result [SF]: ✔️ el8 ✔️ el9 ✔️ el10 ✔️ debian ✔️ suse15. SL-JID 17709

[sureshanaparti]

@blueorangutan package

[blueorangutan]

@sureshanaparti 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.