如何通过Ingress weight分发请求

Ingress如何根据weight分发用户请求，从而控制某一服务的访问占比。

Ingress提供了canary功能，可以通过nginx.ingress.kubernetes.io/canary-weight 设置对某一服务访问流量的权重。

1.部署两个 echoserver 用于测试

$ kubectl get pod -n default 
NAME                         READY   STATUS    RESTARTS   AGE
canary-5978bccbf6-x44t8      1/1     Running   0          8s
production-8ffb86cb4-gvzc8   1/1     Running   0          5m24s

$ kubectl get svc -n default 
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE
canary       ClusterIP   10.99.3.0       <none>        80/TCP    17s
production   ClusterIP   10.99.224.239   <none>        80/TCP    5m33s

# 访问production svc
$ root@k8s-master01:/usr/local/src/canary# curl 10.99.224.239


Hostname: production-8ffb86cb4-gvzc8

Pod Information:
        node name:      192.168.0.75
        pod name:       production-8ffb86cb4-gvzc8
        pod namespace:  default
        pod IP: 10.233.87.35

Server values:
        server_version=nginx: 1.13.3 - lua: 10008

Request Information:
        client_address=10.233.15.89
        method=GET
        real path=/
        query=
        request_version=1.1
        request_scheme=http
        request_uri=http://10.99.224.239:8080/

Request Headers:
        accept=*/*
        host=10.99.224.239
        user-agent=curl/7.68.0

Request Body:
        -no body in request-

# 访问canary svc
$ curl 10.99.3.0


Hostname: canary-5978bccbf6-x44t8

Pod Information:
        node name:      192.168.0.75
        pod name:       canary-5978bccbf6-x44t8
        pod namespace:  default
        pod IP: 10.233.90.160

Server values:
        server_version=nginx: 1.13.3 - lua: 10008

Request Information:
        client_address=10.233.15.89
        method=GET
        real path=/
        query=
        request_version=1.1
        request_scheme=http
        request_uri=http://10.99.3.0:8080/

Request Headers:
        accept=*/*
        host=10.99.3.0
        user-agent=curl/7.68.0

Request Body:
        -no body in request-

2.创建ingress

$ cat production-ingress.yaml 
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: production
spec:
  ingressClassName: nginx      
  rules:
  - host: "prod.xxx.com"
    http:
      paths:
      - pathType: Prefix
        path: /
        backend:
          service:
            name: production
            port:
              number: 80

$ cat canary-weight-ingress.yaml 
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: canary-weight
  annotations:
    nginx.ingress.kubernetes.io/canary: "true"
    nginx.ingress.kubernetes.io/canary-weight: "30"  
spec:
  ingressClassName: nginx      
  rules:
  - host: "prod.xxx.com"
    http:
      paths:
      - pathType: Prefix
        path: /
        backend:
          service:
            name: canary
            port:
              number: 80

$ kubectl apply -f production-ingress.yaml
$ kubectl apply -f canary-weight-ingress.yaml 
$ kubectl get ingress -n default 
NAME            CLASS   HOSTS          ADDRESS         PORTS   AGE
canary-weight   nginx   prod.xxx.com   10.99.115.162   80      91s
production      nginx   prod.xxx.com   10.99.115.162   80      2m5s

3.验证

$ c=0;p=0;for i in $(seq 1000); do result=$(curl -s prod.xxx.com:32080 | grep  Hostname | awk -F: '{print $2}'); [[ ${result} =~ ^[[:space:]]canary ]] && let c++ || let p++; done;echo "production:${p}; canary:${c};"
production:721; canary:280;

[1] https://kubernetes.github.io/ingress-nginx/user-guide/nginx-configuration/annotations/#canary 如果您有其他问题，欢迎您联系火山引擎技术支持服务