k8s svc负载均衡

## k8s svc负载均衡

- run创建deploy

```bash

[root@zjucst-52668 ~]#   kubectl run http --image=katacoda/docker-http-server:latest --replicas=1 -n cka

```

- expose创建svc，暴露ip端口,并且为其配置虚拟网卡

```bash

[root@zjucst-52668 ~]#   274  kubectl expose deployment http --external-ip="172.17.0.1" --port=8000 --target-port=80 -n cka

[root@zjucst-52668 ~]#   ifconfig eth0:cka 172.17.0.1 up

```

- scale水平扩容pods

```bash

[root@zjucst-52668 ~]#    kubectl scale deployment http --replicas=3 -ncka

[root@zjucst-52668 ~]# kubectl get pods -n cka

NAME                   READY     STATUS    RESTARTS   AGE

http-989f8bcf9-gvjdf   1/1       Running   0          11s

http-989f8bcf9-jk556   1/1       Running   0          32m

http-989f8bcf9-p66hp   1/1       Running   0          11s

[root@zjucst-52668 ~]# 

[root@zjucst-52668 ~]# kubectl describe svc http -ncka

Name:              http

Namespace:         cka

Labels:            run=http

Annotations:       <none>

Selector:          run=http

Type:              ClusterIP

IP:                10.247.204.130

External IPs:      172.17.0.1

Port:              <unset>  8000/TCP

TargetPort:        80/TCP

Endpoints:         172.16.0.43:80,172.16.0.44:80,172.16.0.45:80

Session Affinity:  None

Events:            <none>

```

- 访问svc ip:port，将会随机得到不同pod的相应

```bash

[root@zjucst-52668 ~]# kubectl get svc -ncka

NAME      TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE

http      ClusterIP   10.247.204.130   172.17.0.1    8000/TCP   22m

[root@zjucst-52668 ~]# kubectl describe svc http -ncka

Name:              http

Namespace:         cka

Labels:            run=http

Annotations:       <none>

Selector:          run=http

Type:              ClusterIP

IP:                10.247.204.130

External IPs:      172.17.0.1

Port:              <unset>  8000/TCP

TargetPort:        80/TCP

Endpoints:         172.16.0.43:80,172.16.0.44:80,172.16.0.45:80

Session Affinity:  None

Events:            <none>

[root@zjucst-52668 ~]# 

[root@zjucst-52668 ~]# curl 172.17.0.1:8000

<h1>This request was processed by host: http-989f8bcf9-gvjdf</h1>

[root@zjucst-52668 ~]# curl 172.17.0.1:8000

<h1>This request was processed by host: http-989f8bcf9-p66hp</h1>

[root@zjucst-52668 ~]# curl 172.17.0.1:8000

<h1>This request was processed by host: http-989f8bcf9-jk556</h1>

[root@zjucst-52668 ~]# 

```