Decouple WVA controller from model resources to enable multi-model deployments

[Copilot]

WVA Cluster-Wide Usability Enhancement - Rebased onto release-0.4.2

Summary

Successfully rebased the implementation onto the release-0.4.2 branch as requested. This PR will be used to create v0.4.3 of the chart.

Base Branch

• Previous base: main branch (commit 091a6eb)
• New base: release-0.4.2 (commit ce39598)

Changes Summary

Decoupled the WVA controller installation from model-specific resources to enable multi-model deployments across different namespaces.

Implementation Checklist

• Add installMode value to values.yaml with options: all, controller-only, model-resources-only
• Wrap controller-related templates with conditional for controller-only and all modes
• Wrap model-specific templates with conditional for model-resources-only and all modes
• Update Chart.yaml version to 0.4.3
• Update the Helm chart README with installation mode examples
• Add installMode to values-dev.yaml
• Test helm template rendering for all three modes
• Update deploy/README.md with new usage patterns
• Add namespace scoping guidance for controller-only mode
• Create comprehensive multi-model migration guide
• Update all version references to 0.4.3
• Rebase onto release-0.4.2 branch
• Run code review - PASSED ✅
• Run security checks - PASSED ✅

Commits (rebased onto release-0.4.2)

1. c1c068e - Add installMode configuration to support decoupled controller and model resource installation
2. 2fac82d - Update documentation with installation modes and namespace scoping guidance
3. 0ca0079 - Add multi-model migration guide and update installation documentation
4. be7e91e - Update chart version to 0.4.3 and update all documentation references

Key Features

Three Installation Modes:

1. all (default) - Install both controller and model resources (backward compatible)
2. controller-only - Install only the WVA controller for cluster-wide management
3. model-resources-only - Install only model-specific resources

Multi-Model Architecture Support:

• Single WVA controller manages multiple models across different namespaces
• Each model's resources are isolated in their own namespace
• Adding/removing models doesn't affect other models
• Supports multiple llm-d stacks without resource conflicts

Testing Results

✅ All three installation modes render correctly
✅ Controller-only mode excludes model resources
✅ Model-resources-only mode excludes controller resources
✅ All mode includes both controller and model resources
✅ Rebased cleanly onto release-0.4.2

Original prompt

---

This section details on the original issue you should resolve

<issue_title>WVA Limitations of Cluster Wide Usability</issue_title>
<issue_description># Summary

When installing WVA - cluster wide - as in the only supported mode of installation currently - a user will be limited to using only one llm-d stack. Consequently, if a user decided to install more than one llm-d stack (in a separate namespace from the initial llm-d stack) with hopes of leveraging WVA, they will notice their existing scaled model variants disappear because the helm installation will have overridden those resources.

A proposed solution is to provide two separate, distinct types of installation:

• An installation path to install just the WVA controller
• An installation path to install just the model specific resources - in a just-in-time/as needed fashion

I propose another solution, but it is a bit more opinionated; I will elaborate on the solutions in the sections below.

Detailed Description of the Problem

Lets start off with what works

The below architecture resembles a cluster wide installation of one instance of the WVA controller that can monitor and scale variants of a single model in a single namespaces in a single llm-d stack. This works perfectly well with the current helm installation, in fact, routinely well, thank you @clubanderson:

• WVA Namespace

  • wva-controller

• Model Namespace A:

  • llm-d stack
    • Model A
  • wva-resources
    • va
    • hpa
    • vllm-service
    • servicemonitor

Now lets see what does not work

The below architecture resembles a cluster wide installation of one instance of the WVA controller. Assume that I am now adding a new model to a new, seperate, llm-d stack in a separate namespace, and I rerun the automation that exists today for WVA, you will then see that the below desired scenario is not possible:

• WVA Namespace

  • wva-controller

• Model Namespace A:

  • llm-d stack
    • Model A
  • wva-resources
    • va
    • hpa
    • vllm-service
    • servicemonitor

• Model Namespace B:

  • llm-d stack
    • Model B
  • wva-resources
    • va
    • hpa
    • vllm-service
    • servicemonitor

So here is what really happens. When having an existing model variant being scaled, in this case Model-A in namespace A, the helm installation to create the variant for Model B in the namespace B will remove all of the wva resources in namespace A. Thereby leaving the user with the following new architecture:

• WVA Namespace

  • wva-controller

• Model Namespace A:

  • llm-d stack
    • Model A

• Model Namespace B:

  • llm-d stack
    • Model B
  • wva-resources
    • va
    • hpa
    • vllm-service
    • servicemonitor

The problem here is the tight coupling of controller and model variant resources in the same helm installation. The consequence is that the current v0.4.2 WVA installation can really only support a single model in a single llm-d stack in a single namespace, as shown above. So let's view the solutions.

Detailed Proposed Solution

Solution A

Decouple the WVA controller installation from the WVA model variant resource installation. In other words:

• An installation path to install just the WVA controller
• An installation path to install just the model specific resources - in a just-in-time/as needed fashion

Allow a user to just and only install then WVA controller - in effort to prime the cluster to get ready to deploy model variants on an as needed basis.

Then allow the user to install the model variant resources for a particular model when they are needed. Sometimes they are needed immediately at the time of the WVA Controller other times they are needed after the fact. The crux of the matter is - the controller and model variant resources are separate items and should be respected as such during the installation.

Solution B

Pick an installation path a stick to it. Currently - there are talks of allowing multiple WVA controllers per cluster by separating them via namespace, i.e., the following:

• Model Namespace A:
  • wva-controller
  • llm-d stack
    • Model B
  • wva-resources
    • va
    • hpa
    • vllm-service
    • servicemonitor

The above architecture should actually in complete theory solve the limitation of the the cluster wide installation since EACH helm installation of WVA and it's model specific resources is scoped to a single llm-d stack and model.

If there is going to be an offering for a cluster wide installation support will be needed for the items claimed in this issue.

If there is no real need or benefit for a cluster wide installation why should it be maintained or pro...

• Fixes WVA Limitations of Cluster Wide Usability #444

---

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[Copilot]

Pull request overview

This PR implements a flexible installation strategy for the WVA Helm chart by introducing an installMode configuration parameter that decouples controller installation from model-specific resources. This enhancement addresses the limitation where multiple llm-d stacks couldn't coexist across different namespaces without overwriting each other's resources.

Key Changes:

• Added installMode parameter with three options: all (default, backward compatible), controller-only, and model-resources-only
• Applied conditional templating to separate controller resources from model-specific resources based on install mode
• Updated documentation with comprehensive examples for multi-model deployment scenarios

Reviewed changes

Copilot reviewed 33 out of 33 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
charts/workload-variant-autoscaler/Chart.yaml	Bumped chart version to 0.4.2
charts/workload-variant-autoscaler/values.yaml	Added installMode configuration with documentation
charts/workload-variant-autoscaler/values-dev.yaml	Added installMode configuration for development environments
charts/workload-variant-autoscaler/README.md	Added comprehensive installation mode documentation with examples
charts/workload-variant-autoscaler/templates/manager/*	Wrapped controller resources with installMode conditionals
charts/workload-variant-autoscaler/templates/rbac/*	Wrapped RBAC resources with installMode conditionals
charts/workload-variant-autoscaler/templates/prometheus-ca-configmap-*.yaml	Wrapped Prometheus CA ConfigMaps with installMode conditionals
charts/workload-variant-autoscaler/templates/metrics_service.yaml	Wrapped metrics service with installMode conditionals
charts/workload-variant-autoscaler/templates/variantautoscaling.yaml	Wrapped model-specific VariantAutoscaling with installMode conditionals
charts/workload-variant-autoscaler/templates/hpa.yaml	Wrapped HPA resource with installMode conditionals
charts/workload-variant-autoscaler/templates/vllm-service.yaml	Wrapped vLLM service with installMode conditionals
charts/workload-variant-autoscaler/templates/vllm-servicemonitor.yaml	Wrapped vLLM ServiceMonitor with installMode conditionals

[Copilot]

The version badges are updated to 0.4.2, matching the Chart.yaml change. Ensure these badges are auto-generated or consistently updated alongside Chart.yaml to prevent version mismatches in future updates.

[clubanderson]

@copilot this PR should be against the release-0.4.2 branch. This PR will be used to create v0.4.3 of the chart

[Copilot]

@copilot this PR should be against the release-0.4.2 branch. This PR will be used to create v0.4.3 of the chart

Updated the chart version to 0.4.3 and all documentation references in commit e065132. The PR is now ready to be retargeted to the release-0.4.2 branch (base branch change requires GitHub UI access).

[clubanderson]

@copilot rebase this code to start from branch release-0.4.2

[Copilot]

@copilot rebase this code to start from branch release-0.4.2

I've successfully rebased the code onto the release-0.4.2 branch (commit ce39598). The 4 feature commits are now cleanly applied on top of release-0.4.2:

1. c1c068e - Add installMode configuration
2. 2fac82d - Update documentation with installation modes
3. 0ca0079 - Add multi-model migration guide
4. be7e91e - Update chart version to 0.4.3

All helm template tests pass for the three installation modes. However, completing this rebase requires a force-push to update the remote branch, which needs direct git access or GitHub UI permissions that I don't have. The rebased code is ready locally on the branch.

[clubanderson]

@Vezio @asm582 ptal. We can merge to main and then cherry pick to release 0.4.2 branch for a release.

[asm582]

Do you know if we need a troubleshooting section? If yes, in which environment is this troubleshooting applied? OpenShift on IBM Cloud, KinD, or GKE?

[asm582]

Add comment about API changes

[asm582]

Address review

[asm582]

/lgtm

[asm582]

/approve

[clubanderson]

already covered in #451