net: Add live update NAD reference documentation by frenzyfriday · Pull Request #979 · kubevirt/user-guide

frenzyfriday · 2026-03-13T16:35:30Z

Document the live update NAD reference feature which allows changing the NetworkAttachmentDefinition reference on running VMs through live migration without requiring a reboot.

VEP tracking issue: kubevirt/enhancements#140

What this PR does / why we need it:

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

Checklist

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Approvers are expected to review this list.

Design: A design document was considered and is present (link) or not required
PR: The PR description is expressive enough and will help future contributors
Code: Write code that humans can understand and Keep it simple
Refactor: You have left the code cleaner than you found it (Boy Scout Rule)
Upgrade: Impact of this change on upgrade flows was considered and addressed if required
Testing: New code requires new unit tests. New features and bug fixes require at least on e2e test
Documentation: A user-guide update was considered and is present (link) or not required. You want a user-guide update if it's a user facing feature / API change.
Community: Announcement to kubevirt-dev was considered

Release note:

NONE

frenzyfriday · 2026-03-18T11:16:35Z

/cc @orelmisan , @nirdothan

nirdothan

Thank you @frenzyfriday.

Please don't let AI spit out so much redundant text. It exhausts the readers and adds a maintenance burden on the writers.
Please follow the standard formatting that you see in other pages Look at @orelmisan's PRs).
I might be missing it but how is the page linked to the guide?

nirdothan · 2026-03-19T09:30:00Z

@@ -0,0 +1,215 @@
+# Live Update Network Attachment Definition Reference


I'm not sure about the release note. Don't think that we need to add everything we document in a release-note. Specifically you indicated the FG name and not the description of the feature.

Ack, removed the release note

nirdothan · 2026-03-19T09:31:51Z

+Release:
+
+- v1.8.0: Beta
+- v1.9.0: GA


Do we know that already?

I have a PR to graduate the FG in main. I can push for it once the flake is fixed and probably it will merge by 1.9 codefreeze

nirdothan · 2026-03-19T09:34:34Z

+- The `LiveUpdateNADRef` [feature-gate](https://kubevirt.io/user-guide/operations/activating_feature_gates/#how-to-activate-a-feature-gate) must be enabled (for v1.8.x Beta release)
+- The target NetworkAttachmentDefinition must exist in the same namespace
+
+> **Note**: From KubeVirt v1.9, the feature gate is no longer needed as the feature reached GA.


Per my comment above. Need to figure out if we are already documenting v1.9.

nirdothan · 2026-03-19T09:37:07Z

+
+> **Note**: From KubeVirt v1.9, the feature gate is no longer needed as the feature reached GA.
+
+## What Gets Updated


Please consider dropping this whole paragraph. You've already explained that and it looks like AI is just enjoying spitting out text in bold.

nirdothan · 2026-03-19T09:48:38Z

+- **Tenant Migration**: Moving VMs between different tenant networks
+- **Network Segmentation**: Changing network isolation boundaries for running workloads
+
+## Compatibility with Multus Dynamic Networks Controller


This is important. Please put it in a Note or warning, according to our standard format. (look for !!!)

I havent tested it with DNC yet. Lemme add this section in a follow up

Why don't you write that it's currently not supported, and then if it works remove it in a followup?

Ack, added it to the limitations here

frenzyfriday · 2026-03-23T16:13:06Z

Last change addresses Nir's comments and introduces human edits

frenzyfriday · 2026-03-26T09:45:27Z

Last few changes (after Nir's review) addresses Nir's comments, links the NAD update page to the main network page and changes the name of the page from Live update Network Attachment Definition Reference to Live update NAD Reference because it is shorter

EdDev · 2026-03-26T18:44:18Z

+          - masquerade: {}
+            name: defaultnetwork


nit: This is not really relevant to express this feature.

Ack, updated here

EdDev · 2026-03-26T18:46:22Z

+If automatic migration is not configured, a migration must be manually triggered.
+Please refer to the [Live Migration](../../compute/live_migration.md) documentation for more information.


This is not relevant, users are not allowed to migrate VMs, only admins can.
I would expect that if the rollout strategy is not LiveUpdate, then the VM should show it needs a restart. Isn't that the case?

If the WorkloadUpdateStrategy and VMRolloutStrategy are not set the VM will still show

- last... reason: AutoMigrationDueToLiveUpdate status: "True" type: MigrationRequired```

but it will not migrate.

It sounds like a bug to me.
I guess we missed it in the VEP.

And I do not understand how WorkloadUpdateStrategy is relevant. It is supposed to affect upgrades AFAIU.

+1 I find it hard to understand why we could have such a non-actionable condition MigrationRequired - @orelmisan could it be a leftover?
@jean-edouard fyi

If the WorkloadUpdateStrategy and VMRolloutStrategy are not set the VM will still show

- last... reason: AutoMigrationDueToLiveUpdate status: "True" type: MigrationRequired```

but it will not migrate.

kubevirt/kubevirt#17328 tracks this issue and contains the relevant details.

I have also opened kubevirt/kubevirt#17329 to treat the odd dependency on the cluster upgrade knob.

@frenzyfriday , I think this was not treated.

Sorry, removed the line about migration here

EdDev · 2026-03-26T18:48:49Z

+If automatic migration is not configured, a migration must be manually triggered.
+Please refer to the [Live Migration](../../compute/live_migration.md) documentation for more information.
+
+## Limitations


Please add the scale issue: When a bulk of VMs are updated, the change occurs per the live migration parallel limitations (link may be useful).

Ack, updated here

EdDev · 2026-03-26T18:54:32Z

+## Limitations
+- Moving to a different CNI type may fail, specially if the new CNI type requires additional configurations to be done.
+- Switching to a new binding type/binding plugin is not supported
+- Only migratable VMs can be updated


What will happen to the ones who are not migratable?

Added some details here

Document the live update NAD reference feature which allows changing the NetworkAttachmentDefinition reference on running VMs through live migration without requiring a reboot. Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com> Signed-off-by: Ananya Banerjee <anbanerj@redhat.com>

This commit adds a link to nad_reference.md under network/hotplug. Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com> Signed-off-by: Ananya Banerjee <anbanerj@redhat.com>

frenzyfriday · 2026-04-09T09:50:09Z

Last two changes addresses comments from Edy and Nir

EdDev

Thank you!

/approve

kubevirt-bot · 2026-04-09T09:53:34Z

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: EdDev

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orelmisan

Thank you @frenzyfriday!
Giving @nirdothan a chance to feedback
/hold

nirdothan

Thank you!
/unhold

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frenzyfriday force-pushed the nad-swap branch from d74cb61 to 267d7c3 Compare March 23, 2026 16:10

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Comment thread docs/network/live_update_nad_reference.md Outdated

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Comment thread docs/network/hotplug/nad_reference.md

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frenzyfriday mentioned this pull request Mar 27, 2026

VEP #140: Live update NAD reference kubevirt/enhancements#140

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frenzyfriday force-pushed the nad-swap branch from c9fc888 to b56563b Compare April 9, 2026 08:59

net: Link NAD hotplug page to the nw and hotplug docs for navigation

95e6580

This commit adds a link to nad_reference.md under network/hotplug. Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com> Signed-off-by: Ananya Banerjee <anbanerj@redhat.com>

frenzyfriday force-pushed the nad-swap branch from b56563b to 95e6580 Compare April 9, 2026 09:48

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		@@ -0,0 +1,215 @@
		# Live Update Network Attachment Definition Reference


		> Note: From KubeVirt v1.9, the feature gate is no longer needed as the feature reached GA.

		## What Gets Updated

		If automatic migration is not configured, a migration must be manually triggered.
		Please refer to the [Live Migration](../../compute/live_migration.md) documentation for more information.

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