k8s之Istio实现virtualservice基于权重分配流量(1)

Virtual Service实例

基于权重分配流量

• 在未使用Istio时，k8s在上述默认情况下，如果要访问httpd-1，就需要访问httpd-1的service，如果需要httpd-1和httpd-2都要访问的话，就需要创建一个service，将httpd-1和httpd-2都selector，但是在这种情况下用户在访问的时候是轮询的（即httpd-1和httpd-2轮流访问，没法去控制其访问流量权重）
• 在istio之间进行访问时，流量走向是基于istio配置的，如果其中某一方不在istio网格内，那么流量就不会按照istio规则进行分流

# 测试yaml
[root@k8s-master-1 access-weight]# cat deployment.yaml 
---
apiVersion: v1
kind: Namespace
metadata:
  name: web
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: httpd-1
  namespace: web
spec:
  selector:
    matchLabels:
      app: httpd-1
      server: web
  template:
    metadata:
      labels:
        app: httpd-1
        server: web
    spec:
      containers:
      - name: busybox
        image: busybox:1.28
        imagePullPolicy: IfNotPresent
        command: ["/bin/sh","-c","echo 'httpd-1' >> /var/www/index.html; httpd -f -p 80 -h /var/www"]
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: httpd-2
  namespace: web
spec:
  selector:
    matchLabels:
      app: httpd-2
      server: web
  template:
    metadata:
      labels:
        app: httpd-2
        server: web
    spec:
      containers:
      - name: busybox
        image: busybox:1.28
        imagePullPolicy: IfNotPresent
        command: ["/bin/sh","-c","echo 'httpd-2' >> /var/www/index.html; httpd -f -p 80 -h /var/www"]
---
apiVersion: v1
kind: Service
metadata:
  name: httpd-1
  namespace: web
spec:
  selector:
    app: httpd-1
  ports:
  - name: http
    port: 80
    targetPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: httpd-2
  namespace: web
spec:
  selector:
    app: httpd-2
  ports:
  - name: http
    port: 80
    targetPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: httpd
  namespace: web
spec:
  selector:
    server: web
  ports:
  - name: http
    port: 80
    targetPort: 80

# 查看endpoints
[root@k8s-master-1 access-weight]# kubectl get endpoints -n web
NAME      ENDPOINTS                     AGE
httpd     10.70.2.38:80,10.70.2.42:80   15s
httpd-1   10.70.2.42:80                 15s
httpd-2   10.70.2.38:80                 15s

# 查看svc
[root@k8s-master-1 access-weight]# kubectl get svc -n web
NAME      TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)   AGE
httpd     ClusterIP   10.0.21.70    <none>        80/TCP    93s
httpd-1   ClusterIP   10.0.42.178   <none>        80/TCP    93s
httpd-2   ClusterIP   10.0.18.166   <none>        80/TCP    93s

# 对httpd进行访问，可以发现其流量是轮询的
[root@k8s-master-1 access-weight]# curl 10.0.21.70
httpd-2
[root@k8s-master-1 access-weight]# curl 10.0.21.70
httpd-1
[root@k8s-master-1 access-weight]# curl 10.0.21.70
httpd-2
[root@k8s-master-1 access-weight]# curl 10.0.21.70
httpd-1
[root@k8s-master-1 access-weight]# curl 10.0.21.70
httpd-2

# 手工注入一下
[root@k8s-master-1 access-weight]# istioctl kube-inject -f deployment.yaml | kubectl apply -f -
namespace/web unchanged
deployment.apps/httpd-1 configured
deployment.apps/httpd-2 configured
service/httpd-1 unchanged
service/httpd-2 unchanged
service/httpd unchanged

# 查看virtualservice
[root@k8s-master-1 access-weight]# cat virtualservice.yaml 
apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
  name: httpd
spec:
  hosts:
  - httpd.web.svc.cluster.local
  http:
  - route:
    - destination: 
        host: httpd-1.web.svc.cluster.local
      weight: 70
    - destination:
        host: httpd-2.web.svc.cluster.local
      weight: 30


# 部署virtualservice
[root@k8s-master-1 access-weight]# kubectl apply -f virtualservice.yaml 
virtualservice.networking.istio.io/httpd created

# 查看virtualservice
[root@k8s-master-1 access-weight]# kubectl get virtualservice
NAME    GATEWAYS   HOSTS                             AGE
httpd              ["httpd.web.svc.cluster.local"]   30s


# 查看service
[root@k8s-master-1 istio]# kubectl get svc -n web
NAME      TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)   AGE
httpd     ClusterIP   10.0.82.52     <none>        80/TCP    2m48s
httpd-1   ClusterIP   10.0.157.208   <none>        80/TCP    2m48s
httpd-2   ClusterIP   10.0.179.208   <none>        80/TCP    2m48s

# 在istio网格之外进行访问测试，可以发现并没有实现基于权重访问
[root@k8s-master-1 access-weight]# curl 10.0.82.52
httpd-2
[root@k8s-master-1 access-weight]# curl 10.0.82.52
httpd-1
[root@k8s-master-1 access-weight]# curl 10.0.82.52
httpd-2
[root@k8s-master-1 access-weight]# curl 10.0.82.52
httpd-1
[root@k8s-master-1 access-weight]# curl 10.0.82.52
httpd-2
[root@k8s-master-1 access-weight]# curl 10.0.82.52
httpd-1


# 在istio网格内进行访问测试，可以发现访问结果并不是之前的轮询了
[root@k8s-master-1 access-weight]# kubectl run -it --rm busybox --image=busybox:1.28 -- /bin/sh
If you don't see a command prompt, try pressing enter.
/ # wget -q -O - http://httpd.web.svc.cluster.local
httpd-2
/ # wget -q -O - http://httpd.web.svc.cluster.local
httpd-1
/ # wget -q -O - http://httpd.web.svc.cluster.local
httpd-1
/ # wget -q -O - http://httpd.web.svc.cluster.local
httpd-1
/ # wget -q -O - http://httpd.web.svc.cluster.local
httpd-1
/ # wget -q -O - http://httpd.web.svc.cluster.local
httpd-2
/ # wget -q -O - http://httpd.web.svc.cluster.local
httpd-1
/ # wget -q -O - http://httpd.web.svc.cluster.local
httpd-1
/ # wget -q -O - http://httpd.web.svc.cluster.local
httpd-1
/ # wget -q -O - http://httpd.web.svc.cluster.local
httpd-1
/ # wget -q -O - http://httpd.web.svc.cluster.local
httpd-1
/ # wget -q -O - http://httpd.web.svc.cluster.local
httpd-2
/ # wget -q -O - http://httpd.web.svc.cluster.local
httpd-2
/ #