kubernetes系列09—Ingress控制器详解

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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。

 

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：

ingress安装指南：

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

[root@master ingress-nginx]# wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/provider/baremetal/service-nodeport.yaml
[root@master ingress-nginx]# kubectl apply -f service-nodeport.yaml 
service/ingress-nginx created

　　

（3）验证

---查询生产的pod
[root@master ~]# 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
[root@master 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
[root@master ~]# 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

[root@master 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
[root@master ingress]# kubectl apply -f deploy-damo.yaml 
service/myapp created
deployment.apps/myapp-deploy created

　　

（2）查询验证

[root@master ~]# 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
[root@master ~]# 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
[root@master ~]# 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

[root@master 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
[root@master ingress]# kubectl apply -f ingress-myapp.yaml
ingress.extensions/ingress-myapp created

　　

（2）查询验证

[root@master ~]# kubectl get ingress
name            hosts             address   ports     age
ingress-myapp   myapp.along.com             80        140d
[root@master ~]# 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

 

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

[root@master 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
[root@master ingress]# kubectl apply -f tomcat-deploy.yaml 
service/tomcat created
deployment.apps/tomcat-deploy created

　　

（2）查询验证

[root@master ~]# 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
[root@master ~]# 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

[root@master 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
[root@master ingress]# kubectl apply -f ingress-tomcat.yaml 
ingress.extensions/ingress-tomcat created

 

（2）查询验证

[root@master ~]# kubectl get ingress
name             hosts              address   ports     age
ingress-myapp    myapp.along.com              80        17m
ingress-tomcat   tomcat.along.com             80        6s
[root@master ~]# 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

 

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

[root@master ingress]# openssl genrsa -out tls.key 2048
generating rsa private key, 2048 bit long modulus
.............................................+++
...............+++
e is 65537 (0x10001)
[root@master ingress]# ls *key
tls.key

　　

（2）创建证书

[root@master ingress]# openssl req -new -x509 -key tls.key -out tls.crt -subj /c=cn/st=beijing/l=beijing/o=devops/cn=tomcat.along.com
[root@master ingress]# ls tls.*
tls.crt  tls.key

　　

（3）创建secret

[root@master ingress]# kubectl create secret tls tomcat-ingress-secret --cert=tls.crt --key=tls.key
secret/tomcat-ingress-secret created
[root@master ingress]# kubectl get secret
name                              type                                  data      age
tomcat-ingress-secret             kubernetes.io/tls                     2         8s
[root@master 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

[root@master 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

[root@master ~]# 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
[root@master ~]# 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