编写两个镜像以方便操作

[root@master httpd]# cat Dockerfile 
FROM busybox

RUN mkdir /data && \
    echo "test page on v1" > /data/index.html

ENTRYPOINT ["/bin/httpd","-f","-h","/data"]

FROM busybox

RUN mkdir /data && \
    echo "test page on v2" > /data/index.html

ENTRYPOINT ["/bin/httpd","-f","-h","/data"]

注意：此为测试镜像，只是为展示操作

查看镜像

[root@master httpd]# docker images
REPOSITORY                                                        TAG        IMAGE ID       CREATED         SIZE
dengzichen/httpd                                                  v1         37e49703bcb5   4 minutes ago   1.24MB
dengzichen/httpd                                                  v2         911a41ce1512   5 minutes ago   1.24MB
busybox                                                           latest     ffe9d497c324   13 days ago     1.24MB

使用K8s来使用镜像

[root@master ~]# kubectl create deploy httpd --image dengzichen/httpd:v1 --replicas 3
deployment.apps/httpd created

[root@master ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
httpd-7f6fd56575-g5m5d   1/1     Running   0          36s
httpd-7f6fd56575-t5r2s   1/1     Running   0          36s
httpd-7f6fd56575-xxk8g   1/1     Running   0          36s

[root@master ~]# kubectl expose deploy httpd --port 80 --type NodePort
service/httpd exposed
[root@master ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
httpd        NodePort    10.96.115.185   <none>        80:30296/TCP   9s
kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP        9h

[root@master ~]# curl http://10.96.115.185
test page on v1

更新

[root@master ~]# kubectl set image deploy/httpd httpd=dengzichen/httpd:v2
deployment.apps/httpd image updated

[root@master ~]# kubectl get pods
NAME                     READY   STATUS              RESTARTS   AGE
httpd-599c45c854-qzgts   0/1     ContainerCreating   0          3s
httpd-7f6fd56575-g5m5d   1/1     Running             0          16m
httpd-7f6fd56575-t5r2s   1/1     Running             0          16m
httpd-7f6fd56575-xxk8g   1/1     Running             0          16m

[root@master ~]# kubectl get pods
NAME                     READY   STATUS        RESTARTS   AGE
httpd-599c45c854-7jpcb   1/1     Running       0          3s
httpd-599c45c854-fhpnb   1/1     Running       0          2s
httpd-599c45c854-qzgts   1/1     Running       0          12s
httpd-7f6fd56575-g5m5d   1/1     Terminating   0          16m
httpd-7f6fd56575-t5r2s   1/1     Terminating   0          16m
httpd-7f6fd56575-xxk8g   1/1     Terminating   0          16m

[root@master ~]# curl http://10.96.115.185
test page on v2

回滚

[root@master ~]# kubectl rollout undo deploy/httpd
deployment.apps/httpd rolled back

[root@master ~]# curl http://10.96.115.185
test page on v1

注意：只会回滚到上一个版本，也就是说，你从新版本回滚到旧版本，再回滚则回到新版本，不会往前推。