fix helm chart support for gke v1alpha2.

[zetxqx]

What type of PR is this?
/kind bug
/kind helm

What this PR does / why we need it:
The current GKE helm chart is not working well with v1alpha2 version.

Verified the current fix working by the following step

1. create model server, use model sim for easy deploy

apiVersion: apps/v1
kind: Deployment
metadata:
  name: vllmsim
spec:
  replicas: 1
  selector:
    matchLabels:
      app: vllmsim
  template:
    metadata:
      labels:
        app: vllmsim
    spec:
      containers:
      - name: vllm-sim
        image: ghcr.io/llm-d/llm-d-inference-sim:v0.3.0
        imagePullPolicy: Always
        args:
        - --model
        - meta-llama/Llama-3.1-8B-Instruct
        - --port
        - "8000"
        - --max-loras
        - "2"
        - --lora-modules
        - '{"name": "food-review-1"}'
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        ports:
        - containerPort: 8000
          name: http
          protocol: TCP
        resources:
          requests:
            cpu: 10m

2. install helm

helm install vllminfpool ./config/charts/inferencepool \
--set inferencePool.modelServers.matchLabels.app=vllmsim \
--set provider.name=gke \
--set inferencePool.apiVersion=inference.networking.x-k8s.io/v1alpha2

3. install gateway and httproute

kubectl apply -f https://github.com/kubernetes-sigs/gateway-api-inference-extension/raw/main/config/manifests/gateway/gke/gateway.yaml

kubectl apply -f - <<EOF
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: llm-route
spec:
  parentRefs:
  - group: gateway.networking.k8s.io
    kind: Gateway
    name: inference-gateway
  rules:
  - backendRefs:
    - group: inference.networking.x-k8s.io
      kind: InferencePool
      name: vllminfpool
    matches:
    - path:
        type: PathPrefix
        value: /
EOF

Which issue(s) this PR fixes:

NONE

Does this PR introduce a user-facing change?:

NONE

[k8s-ci-robot]

@zetxqx: The label(s) kind/helm cannot be applied, because the repository doesn't have them.

In response to this:

What type of PR is this?
/kind bug
/kind helm

What this PR does / why we need it:
The current GKE helm chart is not working well with v1alpha2 version.

Verified the current fix working by the following step

1. create model server, use model sim for easy deploy

apiVersion: apps/v1
kind: Deployment
metadata:
 name: vllmsim
spec:
 replicas: 1
 selector:
   matchLabels:
     app: vllmsim
 template:
   metadata:
     labels:
       app: vllmsim
   spec:
     containers:
     - name: vllm-sim
       image: ghcr.io/llm-d/llm-d-inference-sim:v0.3.0
       imagePullPolicy: Always
       args:
       - --model
       - meta-llama/Llama-3.1-8B-Instruct
       - --port
       - "8000"
       - --max-loras
       - "2"
       - --lora-modules
       - '{"name": "food-review-1"}'
       env:
       - name: POD_NAME
         valueFrom:
           fieldRef:
             fieldPath: metadata.name
       - name: NAMESPACE
         valueFrom:
           fieldRef:
             fieldPath: metadata.namespace
       ports:
       - containerPort: 8000
         name: http
         protocol: TCP
       resources:
         requests:
           cpu: 10m

2. install helm

helm install vllminfpool ./config/charts/inferencepool \
--set inferencePool.modelServers.matchLabels.app=vllmsim \
--set provider.name=gke \
--set inferencePool.apiVersion=inference.networking.x-k8s.io/v1alpha2

3. install gateway and httproute

kubectl apply -f https://github.com/kubernetes-sigs/gateway-api-inference-extension/raw/main/config/manifests/gateway/gke/gateway.yaml

kubectl apply -f - <<EOF
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
 name: llm-route
spec:
 parentRefs:
 - group: gateway.networking.k8s.io
   kind: Gateway
   name: inference-gateway
 rules:
 - backendRefs:
   - group: inference.networking.x-k8s.io
     kind: InferencePool
     name: vllminfpool
   matches:
   - path:
       type: PathPrefix
       value: /
EOF

Which issue(s) this PR fixes:

NONE

Does this PR introduce a user-facing change?:

NONE

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

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[nirrozenbaum]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: nirrozenbaum, zetxqx

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