Backport: kvm: truncate vnc password to 8 chars (#6244)

[nvazquez]

Description

This PR backports #6244 to 4.16
(This PR truncates the vnc password of kvm vms to 8 chars to support latest versions of libvirt.)

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)

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?

[NuxRo]

lgtm

[nvazquez]

@blueorangutan package

[blueorangutan]

@nvazquez a 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.

[weizhouapache]

code lgtm

[blueorangutan]

Packaging result: ✔️ el7 ✔️ el8 ✔️ debian ✔️ suse15. SL-JID 3455

[nvazquez]

@blueorangutan test

[blueorangutan]

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

[slavkap]

LGTM

[blueorangutan]

Trillian test result (tid-4219)
Environment: kvm-centos7 (x2), Advanced Networking with Mgmt server 7
Total time taken: 29818 seconds
Marvin logs: https://github.com/blueorangutan/acs-prs/releases/download/trillian/pr6402-t4219-kvm-centos7.zip
Smoke tests completed. 92 look OK, 0 have errors
Only failed tests results shown below:

Test	Result	Time (s)	Test File

[leolleeooleo]

This PR has an another issue when migrate VM which was started before update this PR.

I tried to edit xml (virsh edit i-12-68-VM), but it did not work.
It needs to stop VM and start again.
Is there any way to migrate without stopping the VM?

[nvazquez]

Hi @leolleeooleo are you able to reproduce after the fix? Not sure if possible without stopping the VM, but was wondering how did you manage to start the VM prior to this fix? Was the VM created prior upgrading libvirt maybe?

[leolleeooleo]

Hi @nvazquez
Yes, VM was created prior upgrading libvirt.
For example on two KVM host cluster.
Enable maintenance mode on the first KVM host. Update the system (dnf update), reboot, and disable maintenance mode.
Then it needs to migrate VM from the second KVM host to the first KVM host in order to update the second KVM host.
But the exception occur during migrate VM.

[nvazquez]

@leolleeooleo thanks for the explanation, let me explore if its possible to add a check for the VNC password length before the migration is executed

[nvazquez]

Hi @leolleeooleo I have created this PR to fix the issue: #6404 could you please test it?