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Using istio, I want to create a virtual service to serve a virtual domain/host inside the cluster. So pods inside the cluster can request "http://internal.service.com/path" to reach certain destination services.

One way is to use make all "internal.service.com" host calls to go to istio-ingressgateway.istio-system, and let the gateway envoy handle the routing. But this loss the purpose of service MESH.

So, I'd like to create a virtual service, host=internal.service.com, gateway=mesh so the routing rules can be injected into all pod's sidecars, and the host+path can be accessible inside the pod.

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: internal-service-vs
spec:
  hosts:
    - "internal.service.com"
  gateways:
    - mesh
  http:
    - match:
        - uri:
            prefix: /path
      route:
        - destination:
            host: a-service.namespace.svc.cluster.local
            port:
              number: 5000

but inside the pod, when I request internal.service.com, it says the host's DNS cannot be resolved.

seems like virtual service is just creating a inbound routing rule, I thought it could work as an outbound rule.

so I need to request any service (with header Host: internal.service.com) to use the inbound routing rule.

but how to request to current pod's sidecar? I don't want to let the request to be outside the requesting pod, as that single target will take all the loads.

  • acceptable request destinations are: any-service.ns, any-service.ns.svc.cluster.local, service cluster ip
  • not acceptable request destinations I found: pod ip(why?), 127.0.0.1:15001(chatgpt told me it's the sidecar's HTTP inbound port)
N.Xu
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1 Answers1

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host's dns need to be resolved in the cluster first. So I need to create a ServiceEntry to make internal.service.com to be a valid host first.

then sidecar outbound route interceptor can handle the request and resolve the host.

N.Xu
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