nginx-proxy 访问nginx pod集群

实验目的：

为了更好理解configmap、endpoint、svc、clustip

实验过程：

从代理服务nginx 访问nginx 集群

1 、为了让curl 访问到集群内部返回不是默认的nginx 主页，便于看清楚负载均衡，所以用configmap 更改web nignx 默认访问主页

2 、为了从代理服务器能访问到web nginx 集群， 用configmap 给代理nignx 配置反向代理，代理的地址写集群svc 的地址，端口写集群的端口

1、准备svc

apiVersion: v1
kind: Service
metadata:
  name: nginx-svc
spec:
  clusterIP: 10.96.173.64
  ports:
    - protocol: TCP
      port: 8000
      targetPort: 80
  selector:
     app: nginx

2、准备代理nginx  的configmap

[root@k8s-master1 test]# cat proxy-config.yaml

apiVersion: v1
kind: ConfigMap
metadata:
    name: conf
    namespace: default
data:
  default.conf: |-
    server {
      listen     80;
      server_name  localhost;
      location / {
          proxy_pass http://10.96.173.64:8000/;    
          proxy_set_header X-Real-IP      $remote_addr;
          proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      }
    }

3、准备代理nginx pod

[root@k8s-master1 test]# cat nginx-proxy.yaml  

apiVersion: v1
kind: Pod
metadata:
 name: proxy-nginx
spec:
 containers:
 - name: proxy-nginx
   image: nginx:1.14.2
   imagePullPolicy: IfNotPresent
   ports:
   - containerPort: 80
   volumeMounts:
   - name: config-volume  
     mountPath: /etc/nginx/conf.d/
 volumes:
 - name: config-volume  
   configMap:
     name: conf

4、 准备集群pod  nginx1 、nginx2 的configmap

[root@k8s-master1 test]# cat config1.yaml  

apiVersion: v1
kind: ConfigMap
metadata:
    name: nginx1
    namespace: default
data:
   index.html: |
      nginx1

[root@k8s-master1 test]# cat config2.yaml  

apiVersion: v1
kind: ConfigMap
metadata:
    name: nginx2
    namespace: default
data:
   index.html: |
      nginx2

5、准备pod 集群 nginx1，nginx2

[root@k8s-master1 test]# cat nginx1.yaml  

apiVersion: v1
kind: Pod
metadata:
 name: nginx1
 labels:
   app: nginx
spec:
 containers:
 - name: nginx
   image: nginx:1.14.2
   imagePullPolicy: IfNotPresent
   ports:
   - containerPort: 80
   volumeMounts:
   - name: config-volume  
     mountPath: /usr/share/nginx/html
 volumes:
 - name: config-volume  
   configMap:
     name: nginx1

[root@k8s-master1 test]# cat nginx2.yaml  

apiVersion: v1
kind: Pod
metadata:
 name: nginx2
 labels:
   app: nginx
spec:
 containers:
 - name: nginx
   image: nginx:1.14.2
   imagePullPolicy: IfNotPresent
   ports:
   - containerPort: 80
   volumeMounts:
   - name: config-volume  
     mountPath: /usr/share/nginx/html
 volumes:
 - name: config-volume  
   configMap:
     name: nginx2

测试：

curl 访问代理nginx ，已经访问到集群内部pod 了

因为svc 中的clust ip 是我们写死的，所以即使svc 重拉，代理nginx 依然能访问到，svc 中使用了标签选择器，所以集群扩展后，pod 会自动加入svc中，对应的endpoint 会自动生成

验证扩展：

创建pod3 及对应的configmap

[root@k8s-master1 test]# cat config3.yaml  

apiVersion: v1
kind: ConfigMap
metadata:
    name: nginx3
    namespace: default
data:
   index.html: |
      nginx3

[root@k8s-master1 test]# cat nginx3.yaml  

apiVersion: v1
kind: Pod
metadata:
 name: nginx3
 labels:
   app: nginx
spec:
 containers:
 - name: nginx
   image: nginx:1.14.2
   imagePullPolicy: IfNotPresent
   ports:
   - containerPort: 80
   volumeMounts:
   - name: config-volume  
     mountPath: /usr/share/nginx/html
 volumes:
 - name: config-volume  
   configMap:
     name: nginx3

备注：如果用deploy 部署pod ，则

svc 中的标签选择器 也需要跟deploy 中的一致，不然生成不了endpoint

他特指标签选择器里面定义的标签， 不是容器内的名称，也不是deploy 本身元数据的名称或标签

The Deployment "nginx-deployment" is invalid: spec.template.metadata.labels: Invalid value: map[string]string{"name":"nginx"}: `selector` does not match template `labels

意思是deploy 里面的选择器标签和模板不一致必须一致才能创建该deploy

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80