Fix for race when automatically assigning IP to Vms

[abh1sar]

Description

Fixes: #7907

This PR fixes the issue where two VMs can be assigned the same IP if they are created at the same time.
NetworkOrchestrator.allocateNic() calls guru.alocate() which returns a free IP address.
NetworkOrchestrator.allocateNic() then calls _nicDao.persists()

But guru.allocate() can return same IPs to two VMs if the first VM hasn't persisted the nic to the DB yet.
Doing the whole thing in a transaction might be costly.

So the fix is to check if the IP returned by guru.allocate is already assigned just before persisting the NicVO in a transaction.
Check will be done only for cases where Ipv4 allocation might race.

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

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?

Wasn't possible to reproduce the actual race, but I tested by manually setting values with debugger and verifying that the code does what it is supposed to.

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

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 48 lines in your changes missing coverage. Please review.

Project coverage is 14.98%. Comparing base (b2ef53b) to head (1fb61ae).
Report is 70 commits behind head on 4.19.

Files	Patch %	Lines
...tack/engine/orchestration/NetworkOrchestrator.java	0.00%	41 Missing ⚠️
api/src/main/java/com/cloud/vm/NicProfile.java	0.00%	6 Missing ⚠️
.../java/com/cloud/network/guru/GuestNetworkGuru.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               4.19    #9240      +/-   ##
============================================
+ Coverage     14.96%   14.98%   +0.01%     
- Complexity    11013    11048      +35     
============================================
  Files          5377     5389      +12     
  Lines        469567   470615    +1048     
  Branches      60162    57503    -2659     
============================================
+ Hits          70285    70517     +232     
- Misses       391498   392263     +765     
- Partials       7784     7835      +51     

Flag	Coverage Δ
uitests	4.28% <ø> (-0.02%)	⬇️
unittests	15.69% <0.00%> (+0.01%)	⬆️

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[DaanHoogland]

Check will be done only for cases where Ipv4 allocation might race.

right now, this means when allocating for the GuestNetworkGuru. Can you look at @hsato03 's implementation (together with him) to see if it can be unified?

[rohityadavcloud]

@abh1sar can you review and address outstanding comments? And, can you care to run packaging and smoketests for your own PRs that are ready for review.
@blueorangutan package

[blueorangutan]

@rohityadavcloud 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]: ✖️ el7 ✔️ el8 ✔️ el9 ✖️ debian ✔️ suse15. SL-JID 10097

[sureshanaparti]

@blueorangutan package

[blueorangutan]

@sureshanaparti 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]: ✔️ el7 ✔️ el8 ✔️ el9 ✔️ debian ✔️ suse15. SL-JID 10101

[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]: ✔️ el7 ✔️ el8 ✔️ el9 ✔️ debian ✔️ suse15. SL-JID 10135

[abh1sar]

@blueorangutan test

[blueorangutan]

@abh1sar a [SL] Trillian-Jenkins test job (centos7 mgmt + kvm-centos7) has been kicked to run smoke tests

[blueorangutan]

[SF] Trillian test result (tid-10631)
Environment: kvm-centos7 (x2), Advanced Networking with Mgmt server 7
Total time taken: 41624 seconds
Marvin logs: https://github.com/blueorangutan/acs-prs/releases/download/trillian/pr9240-t10631-kvm-centos7.zip
Smoke tests completed. 131 look OK, 0 have errors, 0 did not run
Only failed and skipped tests results shown below:

Test	Result	Time (s)	Test File

[weizhouapache]

I tried to reproduce the issue on a env without this PR

• create a shared network with 5 IPs (1 for VR, 3 for test vms). deployed 6 vms in parallel, 3 works and 3 failed
  

• create isolated network with netmask 255.255.255.248 (6 IPs in total, 1 for VR, 2 for existing VM, 2 for test vms). deploy 6 vms in parallel

2 vms failed, 4 vms succeeded (3 vms have the same IP)

With this PR (on another env)

• create isolated network with netmask 255.255.255.248 (6 IPs in total, 1 for VR, 3 for existing VM, 2 for test vms). deploy 6 vms in parallel, 2 succeeded, 4 failed. looks nice
  

[weizhouapache]

lgtm

cc @sureshanaparti

[vishesh92]

clgtm