Kubernetes基础：使用Deployment创建Pod

太过爱你忘了你带给我的痛 2023-07-03 07:13 23阅读 0赞

随着RC的退出，Deployment作为Pod的控制器之一使用地越来越广泛，这篇文章以nginx服务为例，介绍一下使用的方式。

# 事前准备 #

本文使用Kubernetes 1.17.2，可参看下文进行快速环境搭建：

*  [单机版本或者集群版本环境搭建][Link 1]

[root@host131 ansible]# kubectl get node -o wide
    NAME              STATUS   ROLES    AGE     VERSION   INTERNAL-IP       EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION          CONTAINER-RUNTIME
    192.168.163.131   Ready    <none>   2m25s   v1.17.2   192.168.163.131   <none>        CentOS Linux 7 (Core)   3.10.0-957.el7.x86_64   docker://19.3.5
    [root@host131 ansible]#

# Deployment配置文件 #

使用如下yaml文件用于设定Deployment

[root@host131 nginx]# cat deployment.yml 
    ---
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: nginx-deployment
    spec:
      replicas: 1
      selector:
        matchLabels:
          app: nginx-app
      template:
        metadata:
          labels:
            app: nginx-app
        spec:
          containers:
          - name: nginx-host
            image: nginx:1.17.8-alpine
            ports:
            - containerPort: 80
    ...
    [root@host131 nginx]#

*  注意事项：matchLabels的内容需要与template中metadata的labels内容匹配，不过不用担心，在创建时会进行检查，比如将matchLabels改为app: nginx-app1，创建时会提示如下错误信息

[root@host131 nginx]# kubectl create -f deployment.yml 
    The Deployment "nginx-deployment" is invalid: spec.template.metadata.labels: Invalid value: map[string]string{"app":"nginx-app1"}: `selector` does not match template `labels`
    [root@host131 nginx]#

# Service配置文件 #

使用如下Service配置文件

[root@host131 nginx]# cat service.yml 
    ---
    apiVersion: v1
    kind: Service
    metadata:
      name: nginx-service
      labels:
        app: nginx-service-app
    spec:
      type: NodePort
      ports:
      - port: 80
        nodePort: 30000
      selector:
        app: nginx-app
    ...
    [root@host131 nginx]#

*  注意事项：selector关联的需要是Deployment中template定义的label。

# 生成Deployment #

使用Deployment的配置文件生成Deployment

[root@host131 nginx]# kubectl create -f deployment.yml 
    deployment.apps/nginx-deployment created
    [root@host131 nginx]#

结果确认

[root@host131 nginx]# kubectl get deployment -o wide |grep nginx
    nginx-deployment   1/1     1            1           34s    nginx-host   nginx:1.17.8-alpine                  app=nginx-app
    [root@host131 nginx]# 
    [root@host131 nginx]# kubectl get pods -o wide |grep nginx
    nginx-deployment-7c5b8fc568-wkh9b   1/1     Running   0          51s    10.254.152.6   192.168.163.131   <none>           <none>
    [root@host131 nginx]# 
    [root@host131 nginx]# 
    [root@host131 nginx]# kubectl exec -it nginx-deployment-7c5b8fc568-wkh9b sh
    / # hostname
    nginx-deployment-7c5b8fc568-wkh9b
    / #

# 生成Service #

[root@host131 nginx]# kubectl create -f service.yml 
    service/nginx-service created
    [root@host131 nginx]#

结果确认

[root@host131 nginx]# kubectl get service -o wide |grep nginx
    nginx-service   NodePort    10.254.77.182   <none>        80:30000/TCP   9s      app=nginx-app
    [root@host131 nginx]#

# nginx使用：集群地址访问 #

在集群所在的集群中，可以使用集群地址+80端口进行访问

[root@host131 nginx]# curl http://10.254.77.182
    <!DOCTYPE html>
    <html>
    <head>
    <title>Welcome to nginx!</title>
    <style> body { width: 35em; margin: 0 auto; font-family: Tahoma, Verdana, Arial, sans-serif; } </style>
    </head>
    <body>
    <h1>Welcome to nginx!</h1>
    <p>If you see this page, the nginx web server is successfully installed and
    working. Further configuration is required.</p>
    
    <p>For online documentation and support please refer to
    <a href="http://nginx.org/">nginx.org</a>.<br/>
    Commercial support is available at
    <a href="http://nginx.com/">nginx.com</a>.</p>
    
    <p><em>Thank you for using nginx.</em></p>
    </body>
    </html>
    [root@host131 nginx]#

也可以利用NodePort端口结合宿主机IP进行访问

[root@host131 nginx]# curl http://192.168.163.131:30000
    <!DOCTYPE html>
    <html>
    <head>
    <title>Welcome to nginx!</title>
    <style> body { width: 35em; margin: 0 auto; font-family: Tahoma, Verdana, Arial, sans-serif; } </style>
    </head>
    <body>
    <h1>Welcome to nginx!</h1>
    <p>If you see this page, the nginx web server is successfully installed and
    working. Further configuration is required.</p>
    
    <p>For online documentation and support please refer to
    <a href="http://nginx.org/">nginx.org</a>.<br/>
    Commercial support is available at
    <a href="http://nginx.com/">nginx.com</a>.</p>
    
    <p><em>Thank you for using nginx.</em></p>
    </body>
    </html>
    [root@host131 nginx]#

当然这种方式也可以直接使用浏览器进行确认  
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# 总结 #

Deployment作为Pod的控制器，可以对Pod进行创建、滚动升级等常见操作，这篇文章以nginx服务为例进行说明，介绍了Deployment和Service在Kubernetes中最常见的使用方式之一。

[Link 1]: https://blog.csdn.net/liumiaocn/article/details/103725251
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