kubernetes系列教程(十八)TKE中实现ingress服务暴露

写在前面

上一篇文章中介绍了基于Nginx实现Ingress Controller的实现，介绍了Nginx Ingress Controller安装、相关功能，TLS，高级特性等介绍，本章开始介绍基于腾讯云TKE实现ingress服务暴露。

1. TKE ingress

1.1 TKE ingress架构

TKE是Tencent Kubernetes Engine即腾讯云基于kubernetes提供的公有云上容器云服务，TKE提供了两种暴露服务的方式：service和ingress。

  • 内网CLB，四层负载均衡，提供VPC内访问，通过node节点的NodePort转发至service；
  • 外网CLB，四层负载均衡，提供公网访问，需要node节点具有访问公网的能力；
  • ingress， 七层负载均衡，提供http和https接入，提供ingress控制器的功能，借助NodePort转发
TKE service和ingress

要使用TKE的ingress功能，需要了解一下相关的组件内容：

  • l7-lb-controller ingress客户端，安装在kube-system，用于解析ingress配置并更新CLB的规则
  • CLB 七层负载均衡，提供ingress controller的功能，根据ingress规则创建http/https监听器，配置转发规则，以NodePort端口绑定后端RS
  • Service 用于ingress服务发现，通过NodePort方式接入CLB
  • 证书 用于提供https接入，配置在CLB负载均衡上，提供CA签名证书，通过Secrets封装给CLB使用

由于nginx ingress controller是直接以Pod的形势部署在kubernetes集群中，借助于service的服务发现可直接实现和pod通讯，而TKE中ingress controller未直接部署在k8s集群中，网络的接入需借助于service的NodePort实现接入，其数据流如下图：

TKE ingress数据流走向

1.2 ingress虚拟主机

环境说明: 创建两个Deployment并以NodePort方式暴露服务，www1.happylau.cn对应tke-app-1服务，同理www2.happylau.cn对应tke-app-2服务，如下演示操作过程：

1、创建两个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、 将两个Deployment以NodePort的方式暴露服务

[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    查看服务列表  [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、定义ingress规则，定义两个host将不同主机转发至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、 应用ingress规则，并查看ingress详情，可以看到ingress创建了一个公网CLB实例

#应用ingress规则  [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详情  [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、测试验证，将IP和域名写入到hosts文件中，访问域名测试验证，如下通过curl解析的方式测试验证

ingress测试验证

6、ingress会创建一个CLB，并在CLB中创建监听器、设置转发规则、绑定后端RS，下图是CLB上自动生成的规则

CLB规则

通过上面演示可知：

  • 自动创建CLB实例
  • CLB实例上配置监听器
  • 配置转发规则
  • 绑定Node节点
  • 绑定端口为service创建的NodePort

1.3 ingress证书加密

TKE支持将在CLB中加载证书实现https加密传输，证书是经过第三方认证的CA签名过的证书，需要先购买好证书，通过Secrets对象在kubernetes集群中定义，如下演示https的实现。

1、 通过Secrets创建证书，先获取到证书的id，如果没有则先创建证书，证书管理，本文以证书id TKPmsWb3 为例，通过stringData能实现base64自动加密

apiVersion: v1  kind: Secret  metadata:    name: ingress-ssl-key  stringData:    qcloud_cert_id: TKPmsWb3  type: Opaque    #生成Secrets对象  [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详情，可得知VEtQbXNXYjM= 已自动通过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    #可以通过base64查看解密后的内容，和配置文件中定义的id一致  [root@VM_10_2_centos ingress]# echo VEtQbXNXYjM= | base64 -d  TKPmsWb3

2、准备环境，创建一个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、将Deployment暴露以NodePort类型暴露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    #类型为NodePort  status:    loadBalancer: {}

4、定义ingress规则，加载证书实现https转发

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、应用ingress规则，并查看详情，此时已正常创建CLB并配置规则

[root@VM_10_2_centos ingress]# kubectl apply -f ingress-demo.yaml  ingress.extensions/tke-ingress-ssl created    #查看ingress详情  [root@VM_10_2_centos ingress]# kubectl describe ingresses tke-ingress-ssl  Name:             tke-ingress-ssl  Namespace:        default  Address:          140.143.83.xxx    #CLB的外网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的实例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、测试验证，hosts文件中解析www.happylauliu.cn到CLB的VIP，或者DNS解析，打开浏览器访问站点，由于是经过CA认证签名的证书，因此没有提示告警信息，查看证书的详情信息

tke ingress ssl验证

7、查看CLB的配置可得知，CLB上配置了443的监听端口，并关联了证书，采用单向认证方式

tke ingres ssl配置规则

通过CLB的配置规则可知，CLB配置了监听443的监听器，80端口并未设置规则，因此此时无法访问http，如何实现在TKE使用ingress实现http和https共存呢，可以通过定义kubernetes.io/ingress.http-rules和

kubernetes.io/ingress.https-rules实现

apiVersion: extensions/v1beta1  kind: Ingress  metadata:    name: tke-ingress-ssl    annotations:      kubernetes.io/ingress.class: qcloud      kubernetes.io/ingress.rule-mix: "true"  #开启混合规则配置，kubernetes.io/ingress.http-rules配置规则      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

设置ingress.http-rules和ingress.https-rules注解之后，会在监听器中创建http和https的转发规则，并绑定RS，此时访问http和https均能实现站点访问，CLB对应的规则内容如下图：

http和https规则混合使用

通过测试访问http://www.happylauliu.cn/和https://www.happylauliu.cn/均能正常访问，如果要实现访问http自动跳转到https，则可以在控制台开启自动跳转的功能，如下图：

开启http自动重定向功能

开启重定向功能后再次访问http站点后此时会自动跳转到https，如下图所示location已经跳转至https://www.happylauliu.cn/

http自动跳转测试

写在最后

通过上述的演示在腾讯云公有云环境下ingress controller的实现，腾讯云TKE通过使用CLB实现和kubernetes ingress集成，借助于service的NodePort实现转发，通过公有云专用的CLB能够最大程度保障ingress接入性能。同时，ingress能够使用腾讯云上的证书实现https加密功能。

参考文献

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证书：https://cloud.tencent.com/document/product/457/40538

CLB配置http自动跳转：https://cloud.tencent.com/document/product/214/8839

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