kubernetes系列教程(十八)TKE中實現ingress服務暴露

關於作者 劉海平（HappyLau ）雲計算高級顧問 目前在騰訊雲從事公有云相關工作，曾就職於酷狗，EasyStack，擁有多年公有云+私有云計算架構設計，運維，交付相關經驗，參與了酷狗，南方電網，國泰君安等大型私有云平臺建設，精通Linux，Kubernetes，OpenStack，Ceph等開源技術，具有豐富RHCA/OpenStack/Linux授課經驗。

寫在前面

上一篇文章中介紹了基於Nginx實現Ingress Controller的實現，介紹了Nginx Ingress Controller安裝、相關功能，TLS，高級特性等介紹，本章開始介紹基於騰訊雲TKE實現ingress服務暴露。

1. TKE ingress

1.1 TKE ingress架構

TKE是Tencent Kubernetes Engine即騰訊雲基於kubernetes提供的公有云上容器雲服務，TKE提供了兩種暴露服務的方式：service和ingress。

• 內網CLB，四層負載均衡，提供VPC內訪問，通過node節點的NodePort轉發至service；
• 外網CLB，四層負載均衡，提供公網訪問，需要node節點具有訪問公網的能力；
• ingress， 七層負載均衡，提供http和https接入，提供ingress控制器的功能，藉助NodePort轉發

要使用TKE的ingress功能，需要了解一下相關的組件內容：

• l7-lb-controller ingress客戶端，安裝在kube-system，用於解析ingress配置並更新CLB的規則
• CLB 七層負載均衡，提供ingress controller的功能，根據ingress規則創建http/https監聽器，配置轉發規則，以NodePort端口綁定後端RS
• Service 用於ingress服務發現，通過NodePort方式接入CLB
• 證書 用於提供https接入，配置在CLB負載均衡上，提供CA簽名證書，通過Secrets封裝給CLB使用

由於nginx ingress controller是直接以Pod的形勢部署在kubernetes集羣中，藉助於service的服務發現可直接實現和pod通訊，而TKE中ingress controller未直接部署在k8s集羣中，網絡的接入需藉助於service的NodePort實現接入，其數據流如下圖：

1.2 ingress虛擬主機

環境說明: 創建兩個Deployment並以NodePort方式暴露服務，www1.happylau.cn對應tke-app-1服務，同理www2.happylau.cn對應tke-app-2服務，如下演示操作過程：

1、創建兩個Deployments

[root@VM_10_2_centos ingress]# kubectl create deployment tke-app-1 --image=nginx:1.7.9
[root@VM_10_2_centos ingress]# kubectl create deployment tke-app-2 --image=nginx:1.7.9

2、 將兩個Deployment以NodePort的方式暴露服務

[root@VM_10_2_centos ~]# kubectl expose deployment tke-app-1 --port=80 --type=NodePort
[root@VM_10_2_centos ~]# kubectl expose deployment tke-app-2 --port=80 --type=NodePort

查看服務列表
[root@VM_10_2_centos ~]# kubectl get services 
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   172.16.255.1     <none>        443/TCP        83d
tke-app-1    NodePort    172.16.255.91    <none>        80:30597/TCP   2s
tke-app-2    NodePort    172.16.255.236   <none>        80:31674/TCP   73s

3、定義ingress規則，定義兩個host將不同主機轉發至backend不同的service

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: tke-ingress-demo
  annotations:
    kubernetes.io/ingress.class: qcloud
spec:
  rules:
  - host: www1.happylau.cn 
    http:
      paths:
      - path: /
        backend:
          serviceName: tke-app-1 
          servicePort: 80 
  - host: www2.happylau.cn 
    http:
      paths:
      - path: /
        backend:
          serviceName: tke-app-2 
          servicePort: 80 

4、 應用ingress規則，並查看ingress詳情，可以看到ingress創建了一個公網CLB實例

#應用ingress規則
[root@VM_10_2_centos ingress]# kubectl apply -f tke-ingress-demo.yaml 
ingress.extensions/tke-ingress-demo created

#查看ingress列表
[root@VM_10_2_centos ingress]# kubectl get ingresses 
NAME               HOSTS                               ADDRESS         PORTS   AGE
tke-ingress-demo   www1.happylau.cn,www2.happylau.cn   140.143.84.xxx   80      67s

#查看 ingress詳情
[root@VM_10_2_centos ingress]# kubectl describe ingresses tke-ingress-demo 
Name:             tke-ingress-demo
Namespace:        default
Address:          140.143.84.xxx
Default backend:  default-http-backend:80 (<none>)
Rules:
  Host              Path  Backends
  ----              ----  --------
  www1.happylau.cn  
                    /   tke-app-1:80 (172.16.1.15:80)
  www2.happylau.cn  
                    /   tke-app-2:80 (172.16.2.17:80)
Annotations:
  kubectl.kubernetes.io/last-applied-configuration:  {"apiVersion":"extensions/v1beta1","kind":"Ingress","metadata":{"annotations":{"kubernetes.io/ingress.class":"qcloud"},"name":"tke-ingress-demo","namespace":"default"},"spec":{"rules":[{"host":"www1.happylau.cn","http":{"paths":[{"backend":{"serviceName":"tke-app-1","servicePort":80},"path":"/"}]}},{"host":"www2.happylau.cn","http":{"paths":[{"backend":{"serviceName":"tke-app-2","servicePort":80},"path":"/"}]}}]}}

  kubernetes.io/ingress.class:                  qcloud
  kubernetes.io/ingress.qcloud-loadbalance-id:  lb-a0xwhcx3
Events:
  Type    Reason           Age                From                     Message
  ----    ------           ----               ----                     -------
  Normal  EnsuringIngress  69s (x3 over 89s)  loadbalancer-controller  Ensuring ingress
  Normal  CREATE           69s (x2 over 70s)  loadbalancer-controller  create loadbalancer succ
  Normal  EnsuredIngress   68s (x3 over 70s)  loadbalancer-controller  Ensured ingress

5、測試驗證，將IP和域名寫入到hosts文件中，訪問域名測試驗證，如下通過curl解析的方式測試驗證

6、ingress會創建一個CLB，並在CLB中創建監聽器、設置轉發規則、綁定後端RS，下圖是CLB上自動生成的規則

通過上面演示可知：

• 自動創建CLB實例
• CLB實例上配置監聽器
• 配置轉發規則
• 綁定Node節點
• 綁定端口爲service創建的NodePort

1.3 ingress證書加密

TKE支持將在CLB中加載證書實現https加密傳輸，證書是經過第三方認證的CA簽名過的證書，需要先購買好證書，通過Secrets對象在kubernetes集羣中定義，如下演示https的實現。

1、 通過Secrets創建證書，先獲取到證書的id，如果沒有則先創建證書，證書管理，本文以證書id TKPmsWb3 爲例，通過stringData能實現base64自動加密

apiVersion: v1
kind: Secret
metadata:
  name: ingress-ssl-key
stringData:
  qcloud_cert_id: TKPmsWb3 
type: Opaque

#生成Secrets對象
[root@VM_10_2_centos ingress]# kubectl apply -f ingress-secret.yaml 
secret/ingress-ssl-key created
[root@VM_10_2_centos ingress]# kubectl get secrets ingress-ssl-key 
NAME              TYPE     DATA   AGE
ingress-ssl-key   Opaque   1      7s

#查看secrets詳情，可得知VEtQbXNXYjM= 已自動通過base64加密
[root@VM_10_2_centos ingress]# kubectl get secrets ingress-ssl-key -o yaml
apiVersion: v1
data:
  qcloud_cert_id: VEtQbXNXYjM=  
kind: Secret
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"v1","kind":"Secret","metadata":{"annotations":{},"name":"ingress-ssl-key","namespace":"default"},"stringData":{"qcloud_cert_id":"TKPmsWb3"},"type":"Opaque"}
  creationTimestamp: "2020-01-03T11:53:33Z"
  name: ingress-ssl-key
  namespace: default
  resourceVersion: "7083702418"
  selfLink: /api/v1/namespaces/default/secrets/ingress-ssl-key
  uid: aaea4a86-2e1f-11ea-a618-ae9224ffad1a
type: Opaque

#可以通過base64查看解密後的內容，和配置文件中定義的id一致
[root@VM_10_2_centos ingress]# echo VEtQbXNXYjM= | base64 -d
TKPmsWb3

2、準備環境，創建一個nginx的Deployment

[root@VM_10_2_centos ~]# kubectl create deployment tke-ingress-ssl-demo --image=nginx:1.7.9
deployment.apps/tke-ingress-ssl-demo created
[root@VM_10_2_centos ~]# kubectl get deployments 
NAME                   READY   UP-TO-DATE   AVAILABLE   AGE
tke-ingress-ssl-demo   1/1     1            1           6s

3、將Deployment暴露以NodePort類型暴露service

[root@VM_10_2_centos ~]# kubectl expose deployment tke-ingress-ssl-demo --port=80 --type=NodePort
service/tke-ingress-ssl-demo exposed
[root@VM_10_2_centos ~]# kubectl get service tke-ingress-ssl-demo -o yaml
apiVersion: v1
kind: Service
metadata:
  creationTimestamp: "2020-01-03T12:00:05Z"
  labels:
    app: tke-ingress-ssl-demo
  name: tke-ingress-ssl-demo
  namespace: default
  resourceVersion: "7083890283"
  selfLink: /api/v1/namespaces/default/services/tke-ingress-ssl-demo
  uid: 94659f42-2e20-11ea-a618-ae9224ffad1a
spec:
  clusterIP: 172.16.255.64
  externalTrafficPolicy: Cluster
  ports:
  - nodePort: 30324
    port: 80
    protocol: TCP
    targetPort: 80
  selector:
    app: tke-ingress-ssl-demo
  sessionAffinity: None
  type: NodePort    #類型爲NodePort
status:
  loadBalancer: {}

4、定義ingress規則，加載證書實現https轉發

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: tke-ingress-ssl
  annotations:
    kubernetes.io/ingress.class: qcloud
    qcloud_cert_id: TKPmsWb3
spec:
  rules:
  - host: www.happylauliu.cn
    http:
      paths:
      - path: /
        backend:
          serviceName: tke-ingress-ssl-demo 
          servicePort: 80
  tls:
  - hosts:
    - www.happylauliu.cn
    secretName: ingress-ssl-key

5、應用ingress規則，並查看詳情，此時已正常創建CLB並配置規則

[root@VM_10_2_centos ingress]# kubectl apply -f ingress-demo.yaml 
ingress.extensions/tke-ingress-ssl created

#查看ingress詳情
[root@VM_10_2_centos ingress]# kubectl describe ingresses tke-ingress-ssl 
Name:             tke-ingress-ssl
Namespace:        default
Address:          140.143.83.xxx    #CLB的外網IP
Default backend:  default-http-backend:80 (<none>)
TLS:
  ingress-ssl-key terminates www.happylauliu.cn
Rules:
  Host                Path  Backends
  ----                ----  --------
  www.happylauliu.cn  
                      /   tke-ingress-ssl-demo:80 (172.16.0.25:80)
Annotations:
  qcloud_cert_id:                                    TKPmsWb3
  kubectl.kubernetes.io/last-applied-configuration:  {"apiVersion":"extensions/v1beta1","kind":"Ingress","metadata":{"annotations":{"kubernetes.io/ingress.class":"qcloud","qcloud_cert_id":"TKPmsWb3"},"name":"tke-ingress-ssl","namespace":"default"},"spec":{"rules":[{"host":"www.happylauliu.cn","http":{"paths":[{"backend":{"serviceName":"tke-ingress-ssl-demo","servicePort":80},"path":"/"}]}}],"tls":[{"hosts":["www.happylauliu.cn"],"secretName":"ingress-ssl-key"}]}}

  kubernetes.io/ingress.class:                  qcloud
  kubernetes.io/ingress.qcloud-loadbalance-id:  lb-2kcrtwbn  #CLB的實例id
Events:
  Type    Reason           Age                From                     Message
  ----    ------           ----               ----                     -------
  Normal  EnsuringIngress  51s (x3 over 73s)  loadbalancer-controller  Ensuring ingress
  Normal  CREATE           51s (x2 over 52s)  loadbalancer-controller  create loadbalancer succ
  Normal  EnsuredIngress   49s (x3 over 52s)  loadbalancer-controller  Ensured ingress

6、測試驗證，hosts文件中解析www.happylauliu.cn到CLB的VIP，或者DNS解析，打開瀏覽器訪問站點，由於是經過CA認證簽名的證書，因此沒有提示告警信息，查看證書的詳情信息

7、查看CLB的配置可得知，CLB上配置了443的監聽端口，並關聯了證書，採用單向認證方式

通過CLB的配置規則可知，CLB配置了監聽443的監聽器，80端口並未設置規則，因此此時無法訪問http，如何實現在TKE使用ingress實現http和https共存呢，可以通過定義kubernetes.io/ingress.http-rules和

kubernetes.io/ingress.https-rules實現

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: tke-ingress-ssl
  annotations:
    kubernetes.io/ingress.class: qcloud
    kubernetes.io/ingress.rule-mix: "true"  #開啓混合規則配置，kubernetes.io/ingress.http-rules配置規則
    kubernetes.io/ingress.http-rules: '[{"host":"www.happylauliu.cn","path":"/","backend":{"serviceName":"tke-ingress-ssl-demo","servicePort":"80"}}]'
    qcloud_cert_id: TKPmsWb3
spec:
  rules:
  - host: www.happylauliu.cn
    http:
      paths:
      - path: /
        backend:
          serviceName: tke-ingress-ssl-demo 
          servicePort: 80
  tls:
  - hosts:
    - www.happylauliu.cn
    secretName: ingress-ssl-key

設置ingress.http-rules和ingress.https-rules註解之後，會在監聽器中創建http和https的轉發規則，並綁定RS，此時訪問http和https均能實現站點訪問，CLB對應的規則內容如下圖：

通過測試訪問http://www.happylauliu.cn/和https://www.happylauliu.cn/均能正常訪問，如果要實現訪問http自動跳轉到https，則可以在控制檯開啓自動跳轉的功能，如下圖：

開啓重定向功能後再次訪問http站點後此時會自動跳轉到https，如下圖所示location已經跳轉至https://www.happylauliu.cn/

寫在最後

通過上述的演示在騰訊雲公有云環境下ingress controller的實現，騰訊雲TKE通過使用CLB實現和kubernetes ingress集成，藉助於service的NodePort實現轉發，通過公有云專用的CLB能夠最大程度保障ingress接入性能。同時，ingress能夠使用騰訊雲上的證書實現https加密功能。

參考文獻

Ingress配置：https://kubernetes.io/docs/concepts/services-networking/ingress/

Ingress控制器：https://kubernetes.io/docs/concepts/services-networking/ingress-controllers/

ingress基本配置：https://cloud.tencent.com/document/product/457/31711

ingress證書：https://cloud.tencent.com/document/product/457/40538

CLB配置http自動跳轉：https://cloud.tencent.com/document/product/214/8839

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