NAS BnR: Restore backed-up volume on live instances is not readable

[abh1sar]

Description

Issues:

1. Restore backed-up volume on live instances attaches the qcow2 volume as a Raw image, which causes the instance to not
   be able to read it.
2. In the cloudstack db the format of the restored volume is kept as Raw (for both live and stopped VMs). Although it doesn't cause any immediate effects, but it might cause some issue with other subsystems like volume migration.

Fix:

1. virsh attach-disk command which is used to attach the restored volume to the live instance should include --subdriver qcow2 argument.
2. NAS backup always converts the disk into Qcow2 format while backing up, so it's safe to set the disk format of the restored volume always to Qcow2 in the db.

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

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

Screenshots (if appropriate):

How Has This Been Tested?

1. Create a VM with a data vol
2. Install ext4 fs on the data vol, mount it and create a file
3. Take NAS backup
4. Create another instance and restore the data vol from the backup to the new instance
5. Try to mount the data vol
   Before fix it throws the following error:
   
   and domainxml shows the disk as raw

       <disk type='file' device='disk'>                                                                                                                                                                                                                                                                                    
      <driver name='qemu' type='raw' cache='none'/>                                                 

After fix these issues are resolved.

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

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 16.13%. Comparing base (b8359e8) to head (5ad1a43).
Report is 100 commits behind head on 4.20.

Files with missing lines	Patch %	Lines
...rg/apache/cloudstack/backup/NASBackupProvider.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               4.20   #10844      +/-   ##
============================================
+ Coverage     16.00%   16.13%   +0.12%     
- Complexity    13104    13217     +113     
============================================
  Files          5651     5651              
  Lines        495841   496759     +918     
  Branches      60044    60183     +139     
============================================
+ Hits          79365    80136     +771     
- Misses       407613   407699      +86     
- Partials       8863     8924      +61     

Flag	Coverage Δ
uitests	4.00% <ø> (+<0.01%)	⬆️
unittests	16.98% <0.00%> (+0.13%)	⬆️

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[Pearl1594]

code lgtm

[abh1sar]

@blueorangutan package

[blueorangutan]

@abh1sar 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.

[blueorangutan]

Packaging result [SF]: ✔️ el8 ✔️ el9 ✔️ debian ✔️ suse15. SL-JID 13336