istio internal GRPC services communication - grpc

Question

I am having trouble having two in-cluster GRPC services (written in netcore3.0) I get Grpc.Core.RpcException: Status(StatusCode=Unavailable, Detail="Connection reset by peer") (with uri = <service>.default.svc.cluster.local) or Grpc.Core.RpcException: Status(StatusCode=Unimplemented, Detail="") with uri = user.default.svc.cluster.local:80. The weird part is all the services work fine if they are communicating from different clusters. I'm I using the right urls. The configuration of one of the services in attached here.
apiVersion: v1
kind: Service
metadata:
name: user
labels:
app: user
service: user
spec:
ports:
- port: 80
name: grpc-port
protocol: TCP
selector:
app: user
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: user-v1
labels:
app: user
version: v1
spec:
replicas: 1
template:
metadata:
labels:
app: user
version: v1
spec:
containers:
- name: user
image: ***
imagePullPolicy: IfNotPresent
env:
- name: GOOGLE_APPLICATION_CREDENTIALS
value: "***"
ports:
- containerPort: 80
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: user
spec:
hosts:
- user.default.svc.cluster.local
http:
- route:
- destination:
port:
number: 80
host: user.default.svc.cluster.local
subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
name: user
spec:
host: user.default.svc.cluster.local
subsets:
- name: v1
labels:
version: v1
---
FIXED: I managed to the it to work by using gRPC's .NETCORE3 client factory integration as described here

Answer 1

Instead of creating a channel and client manually as one would usually do. i.e
var endpoint = "test"; //or http://test
AppContext.SetSwitch("System.Net.Http.SocketsHttpHandler.Http2UnencryptedSupport", true);
Channel channel = new Channel(endpoint, ChannelCredentials.Insecure);
client = new TestService.TestServiceClient(channel);
I used GRPC client factory integration (in ConfigureServices (startup.cs) like this (after adding Grpc.Net.ClientFactory package version 0.1.22-pre1:
services.AddGrpcClient<TestService.TestServiceClient>(o =>
{
AppContext.SetSwitch("System.Net.Http.SocketsHttpHandler.Http2UnencryptedSupport", true);
o.BaseAddress = new Uri("http://test");
});
Thereafter you can access the client by using Dependency Injection.
I'm not sure why the second approach works but the first one doesn't.