Question 97229 in Nginx Question posted in
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Istio Routing – How to route default traffic to a specific service from istio gateway – Nginx

I am trying to implement following routing strategy in my K8S cluster.

  1. route foo/bar/* requests to bar-service
  2. route foo/* requests (except foo/bar/*) requests to foo-service

I am new to istio and this strategy was already implemented with nginx ingress controller using regex but could not find a way in istio gateway and virtual service.

Tags:

3

Answers


  1. 0

    Try with edit the virtulaservice

    • name: "/foo/bar/"
      match:

      • uri:
        prefix: /foo/bar/*
        rewrite:
        uri: /
        route:
      • destination:
        host: bar-service
        port:
        number: 80
    • name: "foo/*"
      match:

      • uri:
        prefix: /foo/*
        rewrite:
        uri: /
        route:
      • destination:
        host: foo-service
        port:
        number: 80
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  2. 0

    This can be accomplished with a VirtualService and HTTP route rules. Let’s say you have App1:

    apiVersion: apps/v1
kind: Deployment
metadata:
  name: app1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: app1
  template:
    metadata:
      labels:
        app: app1
    spec:
      containers:
        - name: app1
          image: ghcr.io/trstringer/httpbin2:0.1.0
          command: ["/httpbin2"]
          args:
            - "--message-hostname"
            - "--port"
            - "8080"
          ports:
            - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: app1
spec:
  selector:
    app: app1
  ports:
    - name: http
      port: 80
      targetPort: 8080

    And a second app, App2:

    apiVersion: apps/v1
kind: Deployment
metadata:
  name: app2
spec:
  replicas: 1
  selector:
    matchLabels:
      app: app2
  template:
    metadata:
      labels:
        app: app2
    spec:
      containers:
        - name: app2
          image: ghcr.io/trstringer/httpbin2:0.1.0
          command: ["/httpbin2"]
          args:
            - "--message-hostname"
            - "--port"
            - "8080"
          ports:
            - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: app2
spec:
  selector:
    app: app2
  ports:
    - name: http
      port: 80
      targetPort: 8080

    In the event that you want app2 to serve all requests to /specific-route, and all other requests to app1, you’d first have to create a Gateway:

    apiVersion: networking.istio.io/v1beta1
kind: Gateway
metadata:
  name: app-routing
spec:
  selector:
    istio: ingressgateway
  servers:
    - port:
        number: 80
        name: http
        protocol: HTTP
      hosts:
        - "httpbin2.com"

    Now wire up a VirtualService to this Gateway, which will handle the routing:

    apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: appvs
spec:
  hosts:
    - "httpbin2.com"
  gateways:
    - app-routing
  http:
    - match:
        - uri:
            prefix: /specific-route
      route:
        - destination:
            host: app2
    - match:
        - uri:
            prefix: /
      route:
        - destination:
            host: app1

    If you look at VirtualService.spec.http you’ll find the list of HTTPRoutes.

    Here is where you define the ordered list of routes. The first one that is matched will be used, so you have to make sure the sub route is listed first.

    Now if you do the following:

    $ curl -H "host: httpbin2.com" http://20.102.18.97/specific-route/more
(app2-75548c4dd9-cjdzd)

    You’ll see the request goes to app2. But if you do a different route that doesn’t match that, it’ll fall back to app1:

    curl -H "host: httpbin2.com" http://20.102.18.97/more/things/here
(app1-549c548585-8cqld)
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  3. 0

    Below virtual service can route requests to different foo, bar service respectively. if further change is required on request path change the regex pattern accordingly

    apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: fooapplication
  namespace: default
spec:
  gateways:
  - foo-gateway
  hosts:
  - '*'
  http:
  - match:
    - uri:
        prefix: /foo
     route:
    - destination:
        host: foo-service
        port:
          number: 8080
  - match:
    - uri:
        regex: /foo.*
    rewrite:
      uri: /bar-service
    route:
    - destination:
        host: bar-service
        port:
          number: 8080
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