nginx对K8s集群中的Service做负载均衡

编写Service.yml文件

[root@master ~]# cat nginx.yml 
---
apiVersion: apps/v1
kind: Deployment
metadata: 
  name: web
spec:
  replicas: 2 
  selector: 
    matchLabels: 
      app: nginx 
  template: 
    metadata: 
      labels: 
        app: nginx
    spec: 
      volumes:
      - name: webstorage
        hostPath: 
          path: /var/www/html
      containers: 
      - name: web
        image: nginx
        imagePullPolicy: IfNotPresent
        volumeMounts: 
        - name: webstorage
          mountPath: /usr/share/nginx/html
...

---
apiVersion: v1
kind: Service
metadata: 
  name: web
spec: 
  type: NodePort
  ports: 
  - port: 80
    targetPort: 80
    protocol: TCP
    nodePort: 30000
  selector: 
    app: nginx

执行

[root@master ~]# kubectl apply -f nginx.yml 
deployment.apps/web created
service/web created

查看

[root@master ~]# kubectl get pod
NAME                  READY   STATUS    RESTARTS   AGE
web-6cfcd88d4-4rh75   1/1     Running   0          5s
web-6cfcd88d4-ql4k6   1/1     Running   0          5s

[root@master ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   10.96.0.1               443/TCP        3d1h
web          NodePort    10.110.225.36           80:30000/TCP   68s

访问测试：

//这里用node1或node2的IP+30000端口号访问
[root@node1 ~]# curl http://192.168.160.124:30000
test1

[root@node2 ~]# curl http://192.168.160.125:30000
test2

另外开一台主机安装nginx做负载均衡用

[root@localhost ~]# yum -y install nginx

修改nginx配置文件

//在server前添加
    upstream webcluster {
        server 192.168.160.124:30000;
        server 192.168.160.125:30000;
    }

//在server里面添加
        location / {
          proxy_pass http://webcluster:30000;
        }

重启Nginx

[root@localhost ~]# systemctl restart nginx.service

[root@localhost ~]# ss -anlt
State      Recv-Q     Send-Q         Local Address:Port          Peer Address:Port     
LISTEN     0          128                  0.0.0.0:80                 0.0.0.0:*        
LISTEN     0          128                  0.0.0.0:22                 0.0.0.0:*        
LISTEN     0          128                     [::]:80                    [::]:*        
LISTEN     0          128                     [::]:22                    [::]:*       

查看IP地址

[root@localhost ~]# ifconfig 
ens160: flags=4163  mtu 1500
        inet 192.168.160.120  netmask 255.255.255.0  broadcast 192.168.160.255
        inet6 fe80::625d:a3c1:31a8:b7ca  prefixlen 64  scopeid 0x20
        ether 00:0c:29:14:34:68  txqueuelen 1000  (Ethernet)
        RX packets 3635  bytes 310215 (302.9 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2960  bytes 429431 (419.3 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 12  bytes 1020 (1020.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 12  bytes 1020 (1020.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

访问

[root@localhost ~]# curl http://127.0.0.1
test1
[root@localhost ~]# curl http://127.0.0.1
test2