使用Deployment运行一个无状态应用

1. 创建一个YAML配置文件 nginx-deployment.yaml

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: nginx-deployment
   spec:
     selector:
       matchLabels:
         app: nginx
     replicas: 2 # 告知 Deployment 运行 2 个与该模板匹配的 Pod
     template:
       metadata:
         labels:
           app: nginx
       spec:
         containers:
         - name: nginx
           image: nginx:1.14.2
           ports:
           - containerPort: 80

2. 提交Deployment配置到k8s集群

   kubectl apply -f nginx-deployment.yaml

3. 检查创建的应用是否成功

   kubectl describe deployment nginx-deployment #显示Deployment信息
   kubectl get pods -l app=nginx #查看Pod列表
   kubectl decribe pod <pod-name> #查看Pod信息

4. 升级nginx版本1.14.2->1.16.1,创建nginx-deployment-update.yaml

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: nginx-deployment
   spec:
     selector:
       matchLabels:
         app: nginx
     replicas: 2
     template:
       metadata:
         labels:
           app: nginx
       spec:
         containers:
         - name: nginx
           image: nginx:1.16.1 # 将 nginx 版本从 1.14.2 更新为 1.16.1
           ports:
           - containerPort: 80

5. 执行nginx更新

   kubectl apply -f nginx-deployment-update.yaml

6. 通过增加副本数来扩容应用,创建nginx-deployment-scale.yaml

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: nginx-deployment
   spec:
     selector:
       matchLabels:
         app: nginx
     replicas: 4 # 将副本数从 2 更新为 4
     template:
       metadata:
         labels:
           app: nginx
       spec:
         containers:
         - name: nginx
           image: nginx:1.16.1
           ports:
           - containerPort: 80

7. 执行扩容动作

   kubectl apply -f nginx-deployment-scale.yaml

8. 检查创建的应用是否扩容成功

   kubectl get pods -l app=nginx #查看Pod列表，2->4