kubernetes系列09—Ingress控制器详解

1、认识Ingress

1.1 什么是Ingress？

　　通常情况下，service和pod仅可在集群内部网络中通过IP地址访问。所有到达边界路由器的流量或被丢弃或被转发到其他地方。从概念上讲，可能像下面这样：

  internet

      |
------------
[ Services ]

Ingress是授权入站连接到达集群服务的规则集合。

internet

     |
[ Ingress ]
--|-----|--
[ Services ]

　　你可以给Ingress配置提供外部可访问的URL、负载均衡、SSL、基于名称的虚拟主机等。用户通过POST Ingress资源到API server的方式来请求ingress。 Ingress controller负责实现Ingress，通常使用负载平衡器，它还可以配置边界路由和其他前端，这有助于以HA方式处理流量。

1.2 Ingress工作示意图

1.3先决条件

　　在使用Ingress resource之前，有必要先了解下面几件事情。Ingress是beta版本的resource，在kubernetes1.1之前还没有。你需要一个Ingress Controller来实现Ingress，单纯的创建一个Ingress没有任何意义。

　　GCE/GKE会在master节点上部署一个ingress controller。你可以在一个pod中部署任意个自定义的ingress controller。你必须正确地annotate每个ingress，比如运行多个ingress controller 和关闭glbc.

　　确定你已经阅读了Ingress controller的beta版本限制。在非GCE/GKE的环境中，你需要在pod中部署一个controller。

1.4 Ingress定义资源清单几个字段

apiVersion： v1 版本
kind： Ingress 类型
metadata 元数据
spec 期望状态
- backend：默认后端，能够处理与任何规则不匹配的请求
- rules：用于配置Ingress的主机规则列表
- tls：目前Ingress仅支持单个TLS端口443
status 当前状态

2、部署一个Ingress

（1）在gitlab上下载yaml文件，并创建部署

gitlab ingress-nginx项目：https://github.com/kubernetes/ingress-nginx

ingress安装指南：https://kubernetes.github.io/ingress-nginx/deploy/

因为需要拉取镜像，所以需要等一段时间

---下载需要的yaml文件

[[email protected] ingress-nginx]# wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/mandatory.yaml
---查询下载成功

[[email protected] ingress-nginx]# ls
mandatory.yaml
---创建ingress

[[email protected] ingress-nginx]# kubectl apply -f mandatory.yaml 

namespace/ingress-nginx created

configmap/nginx-configuration created

configmap/tcp-services created

configmap/udp-services created

serviceaccount/nginx-ingress-serviceaccount created

clusterrole.rbac.authorization.k8s.io/nginx-ingress-clusterrole created

role.rbac.authorization.k8s.io/nginx-ingress-role created

rolebinding.rbac.authorization.k8s.io/nginx-ingress-role-nisa-binding created

clusterrolebinding.rbac.authorization.k8s.io/nginx-ingress-clusterrole-nisa-binding created

deployment.apps/nginx-ingress-controller created

（2）如果是裸机，还需要安装service

[[email protected] ingress-nginx]# wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/provider/baremetal/service-nodeport.yaml

[[email protected] ingress-nginx]# kubectl apply -f service-nodeport.yaml 

service/ingress-nginx created

（3）验证

---查询生产的pod

[[email protected] ~]# kubectl get pods -n ingress-nginx
NAME                                        READY     STATUS    RESTARTS   AGE

nginx-ingress-controller-648c7bb65b-df9qz   1/1       Running   0          34m
---查询生产的svc

[[email protected] ingress-nginx]# kubectl get svc -n ingress-nginx
NAME            TYPE       CLUSTER-IP       EXTERNAL-IP   PORT(S)                      AGE

ingress-nginx   NodePort   10.109.244.123   <none>        80:30080/TCP,443:30443/TCP   21s
---查询svc的详细信息

[[email protected] ~]# kubectl describe svc ingress-nginx -n ingress-nginx
Name:                     ingress-nginx
Namespace:                ingress-nginx

Labels:                   app.kubernetes.io/name=ingress-nginx

                          app.kubernetes.io/part-of=ingress-nginx

Annotations:              kubectl.kubernetes.io/last-applied-configuration={"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"labels":{"app.kubernetes.io/name":"ingress-nginx","app.kubernetes.io/part-of":"ingres...

Selector:                 app.kubernetes.io/name=ingress-nginx,app.kubernetes.io/part-of=ingress-nginx
Type:                     NodePort
IP:                       10.111.143.90

Port:                     http  80/TCP

TargetPort:               80/TCP

NodePort:                 http  30080/TCP
Endpoints:                10.244.1.104:80

Port:                     https  443/TCP

TargetPort:               443/TCP

NodePort:                 https  30443/TCP
Endpoints:                10.244.1.104:443
Session Affinity:         None
External Traffic Policy:  Cluster
Events:                   <none>

3、创建Ingress，代理到后端nginx服务

3.1 准备后端pod和service

（1）编写yaml文件，并创建

创建3个nginx服务的pod，并创建一个service绑定

[[email protected] ingress]# vim deploy-damo.yaml
apiVersion: v1
kind: Service
metadata:

  name: myapp

  namespace: default
spec:

  selector:

    app: myapp

    release: canary

  ports:

  - name: http

    targetPort: 80

    port: 80
---

apiVersion: apps/v1
kind: Deployment
metadata:

  name: myapp-deploy

  namespace: default
spec:

  replicas: 3

  selector:

    matchLabels:

      app: myapp

      release: canary

  template:

    metadata:

      labels:

        app: myapp

        release: canary

    spec:

      containers:

      - name: myapp

        image: ikubernetes/myapp:v2

        ports:

        - name: http

          containerPort: 80

[[email protected] ingress]# kubectl apply -f deploy-damo.yaml 

service/myapp created

deployment.apps/myapp-deploy created

（2）查询验证

[[email protected] ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE

kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP   146d

myapp        ClusterIP   10.103.137.126   <none>        80/TCP    6s

[[email protected] ~]# kubectl get pods
NAME                            READY     STATUS    RESTARTS   AGE

myapp-deploy-67f6f6b4dc-2vzjn   1/1       Running   0          14s

myapp-deploy-67f6f6b4dc-c7f76   1/1       Running   0          14s

myapp-deploy-67f6f6b4dc-x79hc   1/1       Running   0          14s

[[email protected] ~]# kubectl describe svc myapp
Name:              myapp
Namespace:         default
Labels:            <none>

Annotations:       kubectl.kubernetes.io/last-applied-configuration={"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"name":"myapp","namespace":"default"},"spec":{"ports":[{"name":"http","port":80,"targe...
Selector:          app=myapp,release=canary
Type:              ClusterIP
IP:                10.103.137.126

Port:              http  80/TCP

TargetPort:        80/TCP
Endpoints:         10.244.1.102:80,10.244.1.103:80,10.244.2.109:80
Session Affinity:  None
Events:            <none>

3.2 创建ingress，绑定后端nginx服务

（1）编写yaml文件，并创建

[[email protected] ingress]# vim ingress-myapp.yaml

apiVersion: extensions/v1beta1
kind: Ingress
metadata:

  name: ingress-myapp

  namespace: default
spec:

  rules:

  - host: myapp.along.com

    http:

      paths:

      - path:

        backend:

          serviceName: myapp

          servicePort: 80

[[email protected] ingress]# kubectl apply -f ingress-myapp.yaml

ingress.extensions/ingress-myapp created

（2）查询验证

[[email protected] ~]# kubectl get ingress
NAME            HOSTS             ADDRESS   PORTS     AGE
ingress-myapp   myapp.along.com             80        140d

[[email protected] ~]# kubectl describe ingress ingress-myapp
Name:             ingress-myapp
Namespace:        default
Address:          
Default backend:  default-http-backend:80 (<none>)
Rules:

  Host             Path  Backends

  ----             ----  --------

  myapp.along.com  

                      myapp:80 (<none>)
Annotations:

  kubectl.kubernetes.io/last-applied-configuration:  {"apiVersion":"extensions/v1beta1","kind":"Ingress","metadata":{"annotations":{},"name":"ingress-myapp","namespace":"default"},"spec":{"rules":[{"host":"myapp.along.com","http":{"paths":[{"backend":{"serviceName":"myapp","servicePort":80},"path":null}]}}]}}
 
Events:

  Type    Reason  Age   From                      Message

  ----    ------  ----  ----                      -------

  Normal  CREATE  37s   nginx-ingress-controller  Ingress default/ingress-myapp

（3）在集群外，查询服务验证

① 可以先修改一下主机的hosts，因为不是公网域名

192.168.130.103 myapp.along.com

② 访问业务成功

kubernetes系列09—Ingress控制器详解

4、创建Ingress，代理到后端tomcat服务

4.1 准备后端pod和service

（1）编写yaml文件，并创建

创建3个tomcat服务的pod，并创建一个service绑定

[[email protected] ingress]# vim tomcat-deploy.yaml 
apiVersion: v1
kind: Service
metadata:

  name: tomcat

  namespace: default
spec:

  selector:

    app: tomcat

    release: canary

  ports:

  - name: http

    targetPort: 8080

    port: 8080

  - name: ajp

    targetPort: 8009

    port: 8009
---

apiVersion: apps/v1
kind: Deployment
metadata:

  name: tomcat-deploy

  namespace: default
spec:

  replicas: 3

  selector:

    matchLabels:

      app: tomcat

      release: canary

  template:

    metadata:

      labels:

        app: tomcat

        release: canary

    spec:

      containers:

      - name: tomcat

        image: tomcat:8.5.37-jre8-alpine

        ports:

        - name: http

          containerPort: 8080

        - name: ajp

          containerPort: 8009

[[email protected] ingress]# kubectl apply -f tomcat-deploy.yaml 

service/tomcat created

deployment.apps/tomcat-deploy created

（2）查询验证

[[email protected] ~]# kubectl get pods
NAME                            READY     STATUS    RESTARTS   AGE

tomcat-deploy-97d6458c5-hrmrw   1/1       Running   0          1m

tomcat-deploy-97d6458c5-ngxxx   1/1       Running   0          1m

tomcat-deploy-97d6458c5-xchgn   1/1       Running   0          1m

[[email protected] ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)             AGE

kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP             146d

tomcat       ClusterIP   10.98.193.252    <none>        8080/TCP,8009/TCP   1m

4.2 创建ingress，绑定后端tomcat服务

（1）编写yaml文件，并创建

[[email protected] ingress]# vim ingress-tomcat.yaml 

apiVersion: extensions/v1beta1
kind: Ingress
metadata:

  name: ingress-tomcat

  namespace: default
spec:

  rules:

  - host: tomcat.along.com

    http:

      paths:

      - path:

        backend:

          serviceName: tomcat

          servicePort: 8080

[[email protected] ingress]# kubectl apply -f ingress-tomcat.yaml 

ingress.extensions/ingress-tomcat created

（2）查询验证

[[email protected] ~]# kubectl get ingress
NAME             HOSTS              ADDRESS   PORTS     AGE
ingress-myapp    myapp.along.com              80        17m
ingress-tomcat   tomcat.along.com             80        6s

[[email protected] ~]# kubectl describe ingress ingress-tomcat
Name:             ingress-tomcat
Namespace:        default
Address:          
Default backend:  default-http-backend:80 (<none>)
Rules:

  Host              Path  Backends

  ----              ----  --------

  tomcat.along.com  

                       tomcat:8080 (<none>)
Annotations:

  kubectl.kubernetes.io/last-applied-configuration:  {"apiVersion":"extensions/v1beta1","kind":"Ingress","metadata":{"annotations":{},"name":"ingress-tomcat","namespace":"default"},"spec":{"rules":[{"host":"tomcat.along.com","http":{"paths":[{"backend":{"serviceName":"tomcat","servicePort":8080},"path":null}]}}]}}
 
Events:

  Type    Reason  Age   From                      Message

  ----    ------  ----  ----                      -------

  Normal  CREATE  17s   nginx-ingress-controller  Ingress default/ingress-tomcat

（3）在集群外，查询服务验证

① 可以先修改一下主机的hosts，因为不是公网域名

192.168.130.103 tomcat.along.com

② 访问业务成功

kubernetes系列09—Ingress控制器详解

4.3 使用https协议访问服务

4.3.1 创建证书、私钥和secret

（1）创建私钥

[[email protected] ingress]# openssl genrsa -out tls.key 2048
Generating RSA private key, 2048 bit long modulus
.............................................+++
...............+++
e is 65537 (0x10001)

[[email protected] ingress]# ls *key
tls.key

（2）创建证书

[[email protected] ingress]# openssl req -new -x509 -key tls.key -out tls.crt -subj /C=CN/ST=Beijing/L=Beijing/O=DevOps/CN=tomcat.along.com

[[email protected] ingress]# ls tls.*
tls.crt  tls.key

（3）创建secret

[[email protected] ingress]# kubectl create secret tls tomcat-ingress-secret --cert=tls.crt --key=tls.key

secret/tomcat-ingress-secret created

[[email protected] ingress]# kubectl get secret
NAME                              TYPE                                  DATA      AGE

tomcat-ingress-secret             kubernetes.io/tls                     2         8s

[[email protected] ingress]# kubectl describe secret tomcat-ingress-secret
Name:         tomcat-ingress-secret
Namespace:    default
Labels:       <none>
Annotations:  <none>
 

Type:  kubernetes.io/tls
 
Data
====
tls.key:  1675 bytes
tls.crt:  1294 bytes

4.3.2 重新创建ingress，使用https协议绑定后端tomcat服务

（1）编写yaml文件，并创建

[[email protected] ingress]# vim ingress-tomcat-tls.yaml

apiVersion: extensions/v1beta1
kind: Ingress
metadata:

  name: ingress-tomcat-tls

  namespace: default
spec:

  tls:

  - hosts:

    - tomcat.along.com

    secretName: tomcat-ingress-secret

  rules:

  - host: tomcat.along.com

    http:

      paths:

      - path:

        backend:

          serviceName: tomcat

          servicePort: 8080

（2）查询验证

[[email protected] ~]# kubectl get ingress
NAME                 HOSTS              ADDRESS   PORTS     AGE
ingress-myapp        myapp.along.com              80        34m
ingress-tomcat       tomcat.along.com             80        16m
ingress-tomcat-tls   tomcat.along.com             80, 443   8s

[[email protected] ~]# kubectl describe ingress ingress-tomcat-tls
Name:             ingress-tomcat-tls
Namespace:        default
Address:          
Default backend:  default-http-backend:80 (<none>)
TLS:

  tomcat-ingress-secret terminates tomcat.along.com
Rules:

  Host              Path  Backends

  ----              ----  --------

  tomcat.along.com  

                       tomcat:8080 (<none>)
Annotations:

  kubectl.kubernetes.io/last-applied-configuration:  {"apiVersion":"extensions/v1beta1","kind":"Ingress","metadata":{"annotations":{},"name":"ingress-tomcat-tls","namespace":"default"},"spec":{"rules":[{"host":"tomcat.along.com","http":{"paths":[{"backend":{"serviceName":"tomcat","servicePort":8080},"path":null}]}}],"tls":[{"hosts":["tomcat.along.com"],"secretName":"tomcat-ingress-secret"}]}}
 
Events:

  Type    Reason  Age   From                      Message

  ----    ------  ----  ----                      -------

  Normal  CREATE  14s   nginx-ingress-controller  Ingress default/ingress-tomcat-tls

（3）在集群外，查询服务验证

使用https协议，访问业务成功

kubernetes系列09—Ingress控制器详解