更新k8s镜像版本的三种方式

一、知识准备

更新镜像版本是在k8s日常使用中非常常见的一种操作,本文主要介绍更新介绍的三种方法


二、环境准备

组件 版本
OS Ubuntu 18.04.1 LTS
docker 18.06.0-ce


三、准备镜像

首先准备2个不同版本的镜像,用于测试(已经在阿里云上创建好2个不同版本的nginx镜像)

docker pull registry.cn-beijing.aliyuncs.com/mrvolleyball/nginx:v1
docker pull registry.cn-beijing.aliyuncs.com/mrvolleyball/nginx:v2

这两个镜像只有版本号不同,其他的都一样

root@k8s-master:~# docker run -d --rm -p 10080:80 nginx:v1
e88097841c5feef92e4285a2448b943934ade5d86412946bc8d86e262f80a050
root@k8s-master:~# curl http://127.0.0.1:10080
----------
version: v1
hostname: f5189a5d3ad3

四、更新镜像的三种方法

我们首先准备一个yaml文件用于测试:

root@k8s-master:~# more image_update.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: image-deployment
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: image-update
    spec:
      containers:
      - name: nginx
        image: registry.cn-beijing.aliyuncs.com/mrvolleyball/nginx:v1
        imagePullPolicy: Always
---
apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
    selector:
      app: image-update
    ports:
    - protocol: TCP
      port: 10080
      targetPort: 80

简单验证一下:

root@k8s-master:~# kubectl apply -f image_update.yaml
deployment.extensions "image-deployment" created
service "nginx-service" created
root@k8s-master:~# kubectl get svc
NAME            TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)     AGE
nginx-service   ClusterIP   10.254.240.225           10080/TCP   1m
root@k8s-master:~# kubectl get pod  -owide
NAME                                READY     STATUS    RESTARTS   AGE       IP              NODE
image-deployment-58b646ffb6-d4sl7   1/1       Running   0          1m        10.10.169.131   k8s-node2
root@k8s-master:~# curl http://10.254.240.225:10080
----------
version: v1
hostname: image-deployment-58b646ffb6-d4sl7

已经正常工作了,并且当前版本是v1

下面介绍修改镜像的方法

(1)修改配置文件

这应该是最常用的方法了

修改配置文件,将nginx:v1改成nginx:v2

root@k8s-master:~# sed -i 's/nginx:v1/nginx:v2/g' image_update.yaml

应用配置文件:

root@k8s-master:~# kubectl apply -f image_update.yaml
deployment.extensions "image-deployment" configured
service "nginx-service" unchanged
root@k8s-master:~# kubectl get pod  -owide
NAME                                READY     STATUS              RESTARTS   AGE       IP              NODE
image-deployment-55cb946d47-7tzp8   0/1       ContainerCreating   0          16s                 k8s-node1
image-deployment-58b646ffb6-d4sl7   1/1       Terminating         0          11m       10.10.169.131   k8s-node2

等待一段时间之后,v2版本ready之后

root@k8s-master:~# kubectl get pod  -owide
NAME                                READY     STATUS    RESTARTS   AGE       IP              NODE
image-deployment-55cb946d47-7tzp8   1/1       Running   0          1m        10.10.36.119    k8s-node1
root@k8s-master:~# curl http://10.254.240.225:10080
----------
version: v2
hostname: image-deployment-55cb946d47-7tzp8

成功更新为v2

(2)使用patch命令

首先找到deployment:

root@k8s-master:~# kubectl get deploy
NAME               DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
image-deployment   1         1         1            1           20m

通过patch更新:

root@k8s-master:~# kubectl patch deployment image-deployment --patch '{"spec": {"template": {"spec": {"containers": [{"name": "nginx","image":"registry.cn-beijing.aliyuncs.com/mrvolleyball/nginx:v1"}]}}}}'
deployment.extensions "image-deployment" patched

等待一段时间之后:

root@k8s-master:~# curl http://10.254.240.225:10080
----------
version: v1
hostname: image-deployment-58b646ffb6-hbzk9

通过patch更新之后,镜像版本更新回v1

(3)使用set image命令

使用set image命令将镜像版本更新到v2

root@k8s-master:~# kubectl set image deploy image-deployment *=registry.cn-beijing.aliyuncs.com/mrvolleyball/nginx:v2
root@k8s-master:~# curl http://10.254.240.225:10080
----------
version: v2
hostname: image-deployment-55cb946d47-zsdc6

等待一段时间之后,版本又更新到v2

五、小结

● 本文介绍了3种方法更新镜像版本,分别是:配置文件;patch方式;set image方式



至此,本文结束
在下才疏学浅,有撒汤漏水的,请各位不吝赐教...

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