mirror of https://github.com/knative/docs.git
Replace Ingress/RouteRule in sample/knative-routing with VirtualService (#61)
* Replace Ingress/RouteRule in sample/knative-routing with VirtualService * fix typos and update the graph * fix typos
This commit is contained in:
Zhimin Xiang
Ryan Gregg
parent
0500d5f629
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88861c6cbb
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@ -1,16 +1,17 @@
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# Routing across Knative Services
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This example shows how to map multiple Knative services to different paths
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under a single domain name using the Istio Ingress and RouteRule concepts.
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under a single domain name using the Istio VirtualService concept.
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Since Istio is a general-purpose reverse proxy, these directions can also be
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used to configure routing based on other request data such as headers, or even
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to map Knative and external resources under the same domain name.
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In this sample, we set up two web services: "Search" service and "Login"
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service, which simply read in an env variable 'SERVICE_NAME' and prints
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"${SERVICE_NAME} is called". We'll then create an Ingress with host
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"example.com", and routing rules so that example.com/search maps to the Search
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service, and example.com/login maps to the Login service.
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"${SERVICE_NAME} is called". We'll then create a VirtualService with host
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"example.com", and define routing rules in the VirtualService so that
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"example.com/search" maps to the Search service, and "example.com/login" maps
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to the Login service.
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## Prerequisites
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@ -43,99 +44,93 @@ kubectl apply -f sample/knative-routing/sample.yaml
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```
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## Exploring
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Once deployed, you can inspect Knative services with
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```shell
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kubectl get service.knative.dev
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```
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You should see 2 Knative services: Search and Login.
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And you can inspect the corresponding Ingress with
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```shell
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kubectl get Ingress
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```
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You should see 2 Ingress objects:
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A shared Gateway "knative-shared-gateway" is used within Knative service mesh
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for serving all incoming traffic. You can inspect it and its corresponding k8s
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service with
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```shell
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# Check shared Gateway
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kubectl get Gateway -n knative-serving -oyaml
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# Check the corresponding k8s service for the shared gateway
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kubectl get svc knative-ingressgateway -n istio-system -oyaml
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```
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NAME HOSTS ADDRESS PORTS
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login-service-ela-ingress login-service.default.example.com,*.login-service.default.example.com 35.237.65.249 80
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search-service-ela-ingress search-service.default.example.com,*.search-service.default.example.com 35.237.65.249 80
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And you can inspect the deployed Knative services with
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```shell
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kubectl get service.serving.knative.dev
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```
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The login-service-ela-ingress and search-service-ela-ingress are Ingresses corresponding to "Login" service and "Search" service.
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You should see 2 Knative services: search-service and login-service.
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You can directly access "Search" service by running
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```shell
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curl http://35.237.65.249 --header "Host:search-service.default.example.com"
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# Get the ingress IP.
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export GATEWAY_IP=`kubectl get svc knative-ingressgateway -n istio-system -o jsonpath="{.status.loadBalancer.ingress[*]['ip']}"`
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export SERVICE_HOST=`kubectl get route search-service -o jsonpath="{.status.domain}"`
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curl http://${GATEWAY_IP} --header "Host:${SERVICE_HOST}"
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```
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You should see
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```
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Search Service is called !
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```
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Similarly, you can also directly access "Login" service.
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Similarly, you can also directly access "Login" service with
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```shell
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# Get the ingress IP.
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export GATEWAY_IP=`kubectl get svc knative-ingressgateway -n istio-system -o jsonpath="{.status.loadBalancer.ingress[*]['ip']}"`
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export SERVICE_HOST=`kubectl get route login-service -o jsonpath="{.status.domain}"`
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curl http://${GATEWAY_IP} --header "Host:${SERVICE_HOST}"
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```
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You should see
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```
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Login Service is called !
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```
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## Apply Custom Routing Rule
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You can apply the custom routing rule defined in "routing.yaml" file with
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You can apply the custom routing rules defined in "routing.yaml" file with
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```shell
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kubectl apply -f sample/knative-routing/routing.yaml
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```
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The routing.yaml file will generate a new Ingress "entry-ingress" for domain
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"example.com". You can see it by running
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The routing.yaml file will generate a new VirtualService "entry-route" for
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domain "example.com". You can see it by running
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```shell
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kubectl get Ingress
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```
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And you should see "entry-ingress" is added into the Ingress results:
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```
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NAME HOSTS ADDRESS PORTS AGE
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entry-ingress example.com 35.237.65.249 80 4h
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kubectl get VirtualService entry-route -o yaml
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```
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Now you can send request to "Search" service and "Login" service by using
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different URI.
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```shell
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# Get the ingress IP.
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export GATEWAY_IP=`kubectl get svc knative-ingressgateway -n istio-system -o jsonpath="{.status.loadBalancer.ingress[*]['ip']}"`
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# send request to Search service
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curl http://35.237.65.249/search --header "Host:example.com"
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curl http://${GATEWAY_IP}/search --header "Host:example.com"
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# send request to Login service
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curl http://35.237.65.249/login --header "Host:example.com"
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curl http://${GATEWAY_IP}/login --header "Host:example.com"
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```
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You should get the same results as you directly access these services.
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## Exploring Custom Routing Rule
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Besides "entry-ingress" Ingress, there are another 3 objects that are
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generated:
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"entry-service" Service, "entry-route-search" RouteRule and
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"entry-route-login" RouteRule.
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You can inspect the details of each objects by running:
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```shell
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# Check details of entry-service Service:
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kubectl get Service entry-service -o yaml
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# Check details of entry-route-search RouteRule
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kubectl get RouteRule entry-route-search -o yaml
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# Check details of entry-route-login RouteRule
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kubectl get RouteRule entry-route-login -o yaml
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```
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## How It Works
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This is the traffic flow of this sample:
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4 components are defined in order to implement the routing.
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1. Ingress "entry-ingress": a new Ingress entry for routing traffic.
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2. Service "entry-service": a placeholder service needed for setting up Ingress and RouteRule
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3. RouteRule "entry-route-search": a RouteRule that checks if request has URI "
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/search", and forwards the request to "Search" service.
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4. RouteRule "entry-route-login": a RouteRule that checks if request has URI "
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/login", and forwards the request to "Login" service.
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When an external request reaches "entry-ingress" Ingress, the Ingress proxy
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will check if it has "/search" or "/login" URI. If it has, then the host of
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When an external request with host "example.com" reaches
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"knative-shared-gateway" Gateway, the "entry-route" VirtualService will check
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if it has "/search" or "/login" URI. If it has, then the host of
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request will be rewritten into the host of "Search" service or "Login" service
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correspondingly, which actually resets the final destination of the request.
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The host rewriting is defined in RouteRule ""entry-route-search" and "entry-route-login".
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The request with updated host will be forwarded to Ingress proxy again. The
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Ingress proxy checks the updated host, and forwards it to "Search" or "Login"
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service according to its host setting.
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The request with updated host will be forwarded to "knative-shared-gateway"
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Gateway again. The Gateway proxy checks the updated host, and forwards it to
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"Search" or "Login" service according to its host setting.
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## Cleaning up
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@ -1,93 +1,57 @@
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# This is the Ingress exposed as the entry of service mesh defined by user with custom routing rules.
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apiVersion: extensions/v1beta1
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kind: Ingress
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# Copyright 2018 The Knative Authors
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# https://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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apiVersion: networking.istio.io/v1alpha3
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kind: VirtualService
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metadata:
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annotations:
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kubernetes.io/ingress.class: istio
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name: entry-ingress
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name: entry-route
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namespace: default
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spec:
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rules:
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# This is the gateway shared in knative service mesh.
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gateways:
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- knative-shared-gateway.knative-serving.svc.cluster.local
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# Set host to the domain name that you own.
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- host: example.com
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http:
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paths:
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- backend:
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serviceName: entry-service
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servicePort: http
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---
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# This is the placeholder service that backs up the entry Ingress.
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# User does not need to change this component.
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apiVersion: v1
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kind: Service
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metadata:
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name: entry-service
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namespace: default
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spec:
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ports:
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- name: http
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port: 80
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protocol: TCP
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targetPort: 80
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sessionAffinity: None
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type: ClusterIP
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---
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# This is an example of routing rule that redirects requests with URI "/search" prefix
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# to Knative Search service.
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apiVersion: config.istio.io/v1alpha2
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kind: RouteRule
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metadata:
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name: entry-route-search
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namespace: default
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spec:
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destination:
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name: entry-service
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namespace: default
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# Define the rule matching request header with "/search" prefix.
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match:
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request:
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headers:
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uri:
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prefix: "/search"
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rewrite:
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# Rewrite the original host header to the host header of Search service
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# in order to redirect requests to Search service.
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authority: search-service.default.example.com
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route:
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- destination:
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# istio-ingress is the k8s service created by Istio as the actual entry of all traffic incoming to the cluster.
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# Basically here we redirect the request to the cluster entry again with updated header
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# "search-service.default.example.com" so the request will eventually be directed to Search service.
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name: istio-ingress
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namespace: istio-system
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weight: 100
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---
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# This is an example of routing rule that redirects requests with URI "/login" prefix
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# to Knative Login service.
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apiVersion: config.istio.io/v1alpha2
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kind: RouteRule
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metadata:
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name: entry-route-login
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namespace: default
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spec:
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destination:
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name: entry-service
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namespace: default
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# Define the rule matching request header with "/login" prefix.
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match:
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request:
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headers:
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uri:
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prefix: "/login"
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rewrite:
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# Rewrite the original host header to the host header of Login service
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# in order to redirect requests to Login service.
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authority: login-service.default.example.com
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route:
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# istio-ingress is the k8s service created by Istio as the actual entry of all traffic incoming to the cluster.
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# Basically here we redirect the request to the cluster entry again with updated header
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# "login-service.default.example.com" so the request will eventually be directed to Login service.
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- destination:
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name: istio-ingress
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namespace: istio-system
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weight: 100
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hosts:
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- example.com
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http:
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- match:
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- uri:
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prefix: "/search"
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rewrite:
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# Rewrite the original host header to the host header of Search service
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# in order to redirect requests to Search service.
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authority: search-service.default.example.com
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route:
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# knative-ingressgateway is the k8s service created by Knative as the
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# shared gateway of all traffic incoming to the cluster.
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# Basically here we redirect the request to the cluster entry again with
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# updated header "search-service.default.example.com" so the request will
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# eventually be directed to Search service.
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- destination:
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host: knative-ingressgateway.istio-system.svc.cluster.local
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weight: 100
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- match:
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- uri:
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prefix: "/login"
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rewrite:
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# Rewrite the original host header to the host header of Search service
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# in order to redirect requests to Search service.
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authority: login-service.default.example.com
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route:
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# Basically here we redirect the request to the cluster entry again with
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# updated header "login-service.default.example.com" so the request will
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# eventually be directed to LOgin service.
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- destination:
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host: knative-ingressgateway.istio-system.svc.cluster.local
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weight: 100
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