在Serverless Kubernetes(ASK)叢集中使用Nginx Ingress

ASK: Alibaba Cloud Serverless Kubernetes

導讀

不同于阿裡雲ACK叢集預設通過nginx-ingress-controller提供ingress能力，在ASK(Serverless Kubernetes)叢集中預設基于SLB七層轉發提供ingress能力（請參考文檔

https://help.aliyun.com/document_detail/86398.html

）。這樣的優勢是Serverless叢集開箱即用，使用者無需部署任何controller即可建立自己的Ingress資源，更符合Serverless環境的用法。

然而基于SLB七層轉發的ingress與nginx-ingress-controller相比，缺少了一些進階Ingress功能，無法滿足某些客戶場景的需求，比如支援域名path的正則比對等。

是以ASK叢集也提供了與ACK叢集同樣的nginx-ingress-controller，供使用者使用nginx提供的ingress轉發能力。使用者可以根據自己的需求決定選擇兩者之一。下面我們一起來嘗試在ASK叢集中使用nginx-ingress。

部署nginx-ingress-controller

在ASK叢集中部署yaml檔案：

https://github.com/AliyunContainerService/serverless-k8s-examples/blob/master/ingress-nginx/nginx-ingress-controller.yaml

#kubectl apply -f https://raw.githubusercontent.com/AliyunContainerService/serverless-k8s-examples/master/ingress-nginx/nginx-ingress-controller.yaml
service/nginx-ingress-lb created
configmap/nginx-configuration created
configmap/tcp-services created
configmap/udp-services created
serviceaccount/nginx-ingress-controller created
clusterrole.rbac.authorization.k8s.io/nginx-ingress-controller created
clusterrolebinding.rbac.authorization.k8s.io/nginx-ingress-controller created
deployment.apps/nginx-ingress-controller created

# kubectl -n kube-system get pod
NAME                                       READY   STATUS    RESTARTS   AGE
nginx-ingress-controller-c9d8697f6-n4bzs   0/1     Running   0          52s
nginx-ingress-controller-c9d8697f6-p8p6j   0/1     Running   0          52s

# kubectl -n kube-system get svc
NAME               TYPE           CLUSTER-IP     EXTERNAL-IP    PORT(S)                      AGE
metrics-server     ClusterIP      172.19.4.171   <none>         443/TCP                      72d
nginx-ingress-lb   LoadBalancer   172.19.6.118   47.93.131.72   80:32676/TCP,443:30256/TCP   116s           

可以看到一個公網slb已經被建立出來（後端是兩個nginx-ingress-controller pod），這是叢集中所有ingress的入口IP位址。

部署Ingress示例

我們同樣提供了簡單的Coffee和Tea Ingress示例：

https://github.com/AliyunContainerService/serverless-k8s-examples/blob/master/ingress-nginx/ingress-cafe-demo.yaml

需要注意的是Ingress中需要指定如下Annotation，才能保證ingress被nginx-ingress-controller正确處理。

kubernetes.io/ingress.class：nginx

# kubectl apply -f https://raw.githubusercontent.com/AliyunContainerService/serverless-k8s-examples/master/ingress-nginx/ingress-cafe-demo.yamldeployment.extensions/coffee created
service/coffee-svc created
deployment.extensions/tea created
service/tea-svc created
ingress.extensions/cafe-ingress created

# kubectl get pod
NAME                             READY   STATUS             RESTARTS   AGE
coffee-56668d6f78-g7g6p          1/1     Running            0          88s
coffee-56668d6f78-x9ktc          1/1     Running            0          88s
tea-85f8bf86fd-477d2             1/1     Running            0          88s
tea-85f8bf86fd-jlq6b             1/1     Running            0          88s
tea-85f8bf86fd-p4ng4             1/1     Running            0          88s

# kubectl get svc
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE
coffee-svc   ClusterIP   None            <none>        80/TCP     102s
kubernetes   ClusterIP   172.19.0.1      <none>        443/TCP    72d
tea-svc      ClusterIP   None            <none>        80/TCP     102s

# kubectl get ing
NAME           HOSTS              ADDRESS        PORTS   AGE
cafe-ingress   cafe.example.com   47.93.131.72   80      2m1s           

pod和ingress都已建立成功，下面我們嘗試通路Ingress：

# curl -H "Host:cafe.example.com" 47.93.131.72/tea
Server address: 192.168.55.159:80
Server name: default-tea-85f8bf86fd-p4ng4
Date: 14/Nov/2019:09:01:46 +0000
URI: /tea
Request ID: 2c3a87eb89130d62664b640fcbabc74b

# curl -H "Host:cafe.example.com" 47.93.131.72/coffee
Server address: 192.168.55.156:80
Server name: default-coffee-56668d6f78-x9ktc
Date: 14/Nov/2019:09:01:49 +0000
URI: /coffee
Request ID: a4f1d84bb5288a260ecfc5d21ecccff6           

Ingress鍊路通路成功，可以看到上述域名轉發由nginx ingress controller完成。

當運作上述示例成功後，記得清理叢集中的ingress：

kubectl delete -f

https://raw.githubusercontent.com/AliyunContainerService/serverless-k8s-examples/master/ingress-nginx/ingress-cafe-demo.yaml

更多ASK叢集示例請參考：

https://github.com/AliyunContainerService/serverless-k8s-examples