enable istio as a provider + configuring destinationRule

Signed-off-by: greg pereira <[email protected]>

Author: Gregory-Pereira

config/charts/inferencepool/README.md

@@ -16,7 +16,7 @@ To install via the latest published chart in staging  (--version v0 indicates la
 ```txt
 $ helm install vllm-llama3-8b-instruct \
   --set inferencePool.modelServers.matchLabels.app=vllm-llama3-8b-instruct \
-  --set provider.name=[none|gke] \
+  --set provider.name=[none|gke|istio] \
   oci://us-central1-docker.pkg.dev/k8s-staging-images/gateway-api-inference-extension/charts/inferencepool --version v0
 ```
 
@@ -95,7 +95,7 @@ Use `--set inferencePool.modelServerType=triton-tensorrt-llm` to install for Tri
 $ helm install triton-llama3-8b-instruct \
   --set inferencePool.modelServers.matchLabels.app=triton-llama3-8b-instruct \
   --set inferencePool.modelServerType=triton-tensorrt-llm \
-  --set provider.name=[none|gke] \
+  --set provider.name=[none|gke|istio] \
   oci://us-central1-docker.pkg.dev/k8s-staging-images/gateway-api-inference-extension/charts/inferencepool --version v0
 ```
 

config/charts/inferencepool/templates/istio.yaml

@@ -0,0 +1,19 @@
+{{- if eq .Values.provider.name "istio" }}
+---
+{{- if .Values.istio.destinationRule.enabled }}
+apiVersion: networking.istio.io/v1beta1
+kind: DestinationRule
+metadata:
+  name: {{ include "gateway-api-inference-extension.name" . }}
+spec:
+  host: {{ .Values.istio.destinationRule.host | default (printf "%s.%s.svc.cluster.local" (include "gateway-api-inference-extension.name" .) .Release.Namespace) }}
+  trafficPolicy:
+    tls:
+      mode: SIMPLE
+      insecureSkipVerify: true
+    {{- if .Values.istio.destinationRule.trafficPolicy.connectionPool }}
+    connectionPool: 
+      {{- .Values.istio.destinationRule.trafficPolicy.connectionPool | toYaml | nindent 6 }}
+    {{- end }}
+{{- end }}
+{{- end }}

config/charts/inferencepool/values.yaml

@@ -67,6 +67,7 @@ inferencePool:
   # This will soon be deprecated when upstream GW providers support v1, just doing something simple for now.
   targetPortNumber: 8000
 
+# Options: ["gke", "istio", "none"]
 provider:
   name: none
 
@@ -75,3 +76,14 @@ provider:
   gke:
     # Set to true if the cluster is an Autopilot cluster.
     autopilot: false
+
+istio:
+  destinationRule:
+    enabled: true
+    # Provide a way to override the default calculated host
+    host: "" 
+    # Optional: Enables customization of the traffic policy
+    trafficPolicy: {}
+      # connectionPool:
+      #   http:
+      #     maxRequestsPerConnection: 256000