k8s中的Service资源

一、service：提供服务的自动发现和负载均衡，帮助暴露pod端口

二、k8s中的三种ip地址：

node ip：node节点

clusterIP：VIP

pod ip：容器ip

三、创建一个service

apiVersion: v1
kind: Service   #简称svc
metadata:
  name: myweb
spec:
  type: NodePort  #默认ClusterIP
  ports:
    - port: 80          #clusterIP
      nodePort: 30000   #node port
      targetPort: 80    #pod port
  selector:
    app: myweb2

四、启动service服务

[root@k8s-master svc]# kubectl create -f k8s_svc.yaml 
service "myweb" created

五、查看service的vip地址

[root@k8s-master svc]# kubectl get service
NAME         CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
kubernetes   10.254.0.1       <none>        443/TCP        4h
myweb        10.254.135.104   <nodes>       80:30000/TCP   11s

六、查看资源标签

[root@k8s-master svc]# kubectl get pod -o wide --show-labels 
NAME          READY     STATUS    RESTARTS   AGE       IP            NODE        LABELS
nginx-1fcrw   1/1       Running   0          49s       172.18.57.4   10.0.0.12   app=myweb
nginx-1qc9k   1/1       Running   0          49s       172.18.78.3   10.0.0.13   app=myweb
nginx-2z8cn   1/1       Running   0          49s       172.18.57.2   10.0.0.12   app=myweb
nginx-8s8z6   1/1       Running   0          49s       172.18.57.3   10.0.0.12   app=myweb
nginx-nb7ps   1/1       Running   0          49s       172.18.78.4   10.0.0.13   app=myweb

七、把rc资源改成2个，测试负载均衡

[root@k8s-master svc]# kubectl  scale rc nginx --replicas=2
replicationcontroller "nginx" scaled
[root@k8s-master svc]# kubectl get pod -o wide --show-labels 
NAME          READY     STATUS    RESTARTS   AGE       IP            NODE        LABELS
nginx-1qc9k   1/1       Running   0          1m        172.18.78.3   10.0.0.13   app=myweb
nginx-nb7ps   1/1       Running   0          1m        172.18.78.4   10.0.0.13   app=myweb

八、进入容器中编辑nginx的配置文件

[root@k8s-master svc]# kubectl exec -it nginx-1qc9k /bin/bash
root@nginx-1qc9k:/# cd /usr/share/nginx/html/
root@nginx-1qc9k:/usr/share/nginx/html# echo "web01" >index.html 

[root@k8s-master svc]# kubectl exec -it nginx-nb7ps /bin/bash
root@nginx-nb7ps:/# cd /usr/share/nginx/html/
root@nginx-nb7ps:/usr/share/nginx/html# echo "web02" >index.html 

九、curl检查效果

[root@k8s-master svc]# curl 10.0.0.12:30000
web01
[root@k8s-master svc]# curl 10.0.0.12:30000
web01
[root@k8s-master svc]# curl 10.0.0.12:30000
web02

十、查看详情

[root@k8s-master svc]# kubectl describe svc myweb 
Name:			myweb
Namespace:		default
Labels:			<none>
Selector:		app=myweb
Type:			NodePort
IP:			10.254.135.104
Port:			<unset>	80/TCP
NodePort:		<unset>	30000/TCP
Endpoints:		172.18.78.3:80,172.18.78.4:80 #pod ip 地址
Session Affinity:	None
No events.

十一、不是同一个标签不会把myweb2加入负载均衡

[root@k8s-master svc]# kubectl  get pod -o wide --show-labels 
NAME           READY     STATUS    RESTARTS   AGE       IP            NODE        LABELS
nginx-1qc9k    1/1       Running   0          13m       172.18.78.3   10.0.0.13   app=myweb
nginx-nb7ps    1/1       Running   0          13m       172.18.78.4   10.0.0.13   app=myweb
nginx2-1dd3q   1/1       Running   0          42s       172.18.57.3   10.0.0.12   app=myweb2
nginx2-3rkf6   1/1       Running   0          42s       172.18.78.5   10.0.0.13   app=myweb2
nginx2-gbdhk   1/1       Running   0          42s       172.18.57.2   10.0.0.12   app=myweb2
nginx2-jhn0m   1/1       Running   0          42s       172.18.57.4   10.0.0.12   app=myweb2
nginx2-xjzwb   1/1       Running   0          42s       172.18.78.6   10.0.0.13   app=myweb2

[root@k8s-master svc]# kubectl describe svc myweb 
Name:			myweb
Namespace:		default
Labels:			<none>
Selector:		app=myweb
Type:			NodePort
IP:			10.254.135.104
Port:			<unset>	80/TCP
NodePort:		<unset>	30000/TCP
Endpoints:		172.18.78.3:80,172.18.78.4:80
Session Affinity:	None
No events.

十二、修改nodePort端口范围

[root@k8s-master svc]# vim /etc/kubernetes/apiserver 
# Add your own!
KUBE_API_ARGS="--service-node-port-range=3000-50000"