05流量管理原理-1请求路由

整个任务中都使用Bookinfo示例应用程序作为示例。

1. 准备工作

安装好前面的环境

export PATH=$PATH:/root/istio-1.6.2/bin
istioctl version

[root@master ~]# istioctl manifest apply --set profile=demo
[root@master ~]# kubectl get all -nistio-system

[root@master ~]# kubectl edit deployment prometheus -nistio-system
deployment.apps/prometheus edited
        image: docker.io/istio/proxyv2:1.6.2
        imagePullPolicy: IfNotPresent  //如果无法联网，及时修改这里的拉取策略。暂时未找到根源上的修改

[root@master ~]# kubectl edit svc istio-ingressgateway  -nistio-system

 //这里默认的的service.spec.type字段值为LoadBalancer，需改为NodePort，单机实验
[root@master ~]# kubectl edit svc kiali -n istio-system   //账号密码均为admin
   type: NodePort

[root@master ~]# kubectl label namespace default istio-injection=enabled
namespace/default labeled     //default命名空间将注入istio

[root@master ~]# kubectl edit cm  istio-sidecar-injector -nistio-system
configmap/istio-sidecar-injector edited
...
  values: |-
    {
      "global": {
...
        "hub": "docker.io/istio",
        "imagePullPolicy": "IfNotPresent",
  ...修改注入时重新拉取镜像的问题

kubectl apply -f istio-1.6.2/samples/bookinfo/platform/kube/bookinfo.yaml
kubectl apply -f istio-1.6.2/samples/bookinfo/networking/bookinfo-gateway.yaml

关于该任务

istio Bookinfo案例包含4个微服务，其中reviews有三个不同的版本。要说明这导致的问题，在浏览器中访问Bookinfo应用程序的/productpage并刷新几次。你会注意到，有时书评输出包含星级评级，有时不包含。这是因为如果没有显式的默认服务版本来路由，Istio就会以循环的方式将请求路由到所有可用的版本。

此任务的初始目标是应用将所有流量路由到微服务的v1(版本1)的规则。稍后，您将根据HTTP请求头的值将规则应用于路由流量。

测试

多刷新几次http://192.168.1.11:30016/productpage，看到多个版本的页面

立刻登录kiali查看graph http://192.168.1.11:31228/，观察到流量从istio-ingressgateway进入后的走向

这里有4个微服务，details、productpage、ratings、reviews，reviews3个版本

1、应用虚拟服务

要仅路由到一个版本，需要应用虚拟服务来设置微服务的默认版本。在这种情况下，虚拟服务将把所有流量路由到每个微服务的v1。

观察一下destination-rule，与pod的标签匹配关系

[root@master ~]# cat istio-1.6.2/samples/bookinfo/networking/destination-rule-all.yaml
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: productpage
spec:
  host: productpage      //匹配的服务名，查看svc确认
  subsets:
  - name: v1
    labels:             //符合svc的pod需有的标签
      version: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: reviews
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
  - name: v3
    labels:
      version: v3
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: ratings
spec:
  host: ratings
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
  - name: v2-mysql
    labels:
      version: v2-mysql
  - name: v2-mysql-vm
    labels:
      version: v2-mysql-vm
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: details
spec:
  host: details
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
---

[root@master ~]# kubectl get svc productpage -oyaml
spec:
  selector:
    app: productpage 

[root@master ~]# kubectl get svc reviews -oyaml
spec:
  selector:
    app: reviews    //符合reviews的pod有3个标签，v1,v2,v3
[root@master ~]# kubectl describe svc reviews
Endpoints:         10.244.1.68:9080,10.244.1.70:9080,10.244.1.71:9080  
[root@master ~]# kubectl get pod -owide    //这与上面的Endpoints对应
NAME                             READY   STATUS    RESTARTS   AGE    IP            NODE   
reviews-v1-7bccdbbf96-fknxx       2/2     Running   0          140m   10.244.1.71   node1 
reviews-v2-7c9685df46-lh5ln       2/2     Running   0          140m   10.244.1.68   node1 
reviews-v3-58fc46b64-szd4w        2/2     Running   0          140m   10.244.1.70   node1

root@master ~]# kubectl get pods --show-labels   //截取了部分标签
NAME                              READY   STATUS    RESTARTS   AGE   LABELS
productpage-v1-7df7cb7f86-xb7nr app=productpage,version=v1
details-v1-6c9f8bcbcb-qcz2w     app=details,version=v1
ratings-v1-65cff55fb8-wmgtm     app=ratings,version=v1
reviews-v1-7bccdbbf96-fknxx     app=reviews,version=v1
reviews-v2-7c9685df46-lh5ln     app=reviews,version=v2
reviews-v3-58fc46b64-szd4w      app=reviews,version=v3

1.应用默认的目标规则

[root@master ~]# kubectl apply -f istio-1.6.2/samples/bookinfo/networking/destination-rule-all.yaml
destinationrule.networking.istio.io/productpage created
destinationrule.networking.istio.io/reviews created
destinationrule.networking.istio.io/ratings created
destinationrule.networking.istio.io/details created
[root@master ~]# kubectl get destinationrules
NAME          HOST          AGE
details       details       25s
productpage   productpage   25s
ratings       ratings       25s
reviews       reviews       25s

2.运行下面命令应用虚拟服务

[root@master ~]# cat istio-1.6.2/samples/bookinfo/networking/virtual-service-all-v1.yaml
//这里的服务规则全部都route到v1上了
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: productpage
spec:
  hosts:
  - productpage
  http:
  - route:
    - destination:
        host: productpage
        subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
  - reviews
  http:
  - route:
    - destination:
        host: reviews
        subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: ratings
spec:
  hosts:
  - ratings
  http:
  - route:
    - destination:
        host: ratings
        subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: details
spec:
  hosts:
  - details
  http:
  - route:
    - destination:
        host: details
        subset: v1
---

[root@master ~]# kubectl apply -f istio-1.6.2/samples/bookinfo/networking/virtual-service-all-v1.yaml
virtualservice.networking.istio.io/productpage created
virtualservice.networking.istio.io/reviews created
virtualservice.networking.istio.io/ratings created
virtualservice.networking.istio.io/details created

等待几秒钟，等待虚拟服务生效。多次刷新http://192.168.1.11:30016/productpage，页面将不会发生变化。流量指向到v1版本

3. 基于用户的标识进行路由

接下来，您将更改路由配置，以便将来自特定用户的所有流量路由到特定的服务版本。在本例中，来自一个名为Jason的用户的所有流量将被路由到reviews:v2。

[root@master ~]# kubectl get VirtualService reviews -oyaml
apiVersion: networking.istio.io/v1beta1
kind: VirtualService
spec:
  hosts:
  - reviews
  http:
  - route:
    - destination:
        host: reviews
        subset: v1       //上面的实验产生的转发给v1版本

1. 运行以下的命令开启基于用户的路由

[root@master ~]# kubectl apply -f  istio-1.6.2/samples/bookinfo/networking/virtual-service-reviews-test-v2.yaml
[root@master ~]# cat  istio-1.6.2/samples/bookinfo/networking/virtual-service-reviews-test-v2.yaml
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
    - reviews
  http:
  - match:
    - headers:
        end-user:
          exact: jason       //end-user报头包含jason，route到v2
    route:
    - destination:
        host: reviews
        subset: v2
  - route:
    - destination:
        host: reviews
        subset: v1

使用以下命令确定规则的创建

[root@master ~]# kubectl get VirtualService reviews -oyaml
spec:
  hosts:
  - reviews
  http:
  - match:
    - headers:
        end-user:
          exact: jason
    route:
    - destination:
        host: reviews
        subset: v2
  - route:
    - destination:
        host: reviews
        subset: v1

直接刷新测试结果如下：流量只走向了v1，没有登录jason（无密码），不会转向v2。v3没有配置，也不会route

清空试验

[root@master ~]# kubectl delete  -f istio-1.6.2/samples/bookinfo/networking/virtual-service-all-v1.yaml  
//删除virtual-service，再次访问，发现能看到多个画面，恢复到之前的状态