写一个k8s加docker集群的项目案例

好的，以下是一个简单的Kubernetes与Docker集成的项目案例：

项目概述：使用Kubernetes和Docker搭建一个高可用的Web应用程序，应用程序将在多个节点上运行，并且在节点故障时，它们将自动迁移到其他可用节点上。

组件：

1. Docker：用于打包和部署应用程序的容器化技术。

2. Kubernetes：用于容器编排、自动化部署、自动扩展和管理容器化应用程序的开源平台。

3. Nginx：用于反向代理和负载均衡的Web服务器。

4. Flask：用于构建Web应用程序的Python框架。

5. Redis：用于缓存应用程序数据的内存数据库。

步骤：

1. 安装Docker和Kubernetes

2. 构建Web应用程序Docker镜像

   FROM python:3.8-alpine
   COPY requirements.txt /app/
   RUN pip install --no-cache-dir -r /app/requirements.txt
   COPY . /app/
   WORKDIR /app
   CMD ["python", "app.py"]

3. 部署Web应用程序到Kubernetes集群

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: myapp
   spec:
     replicas: 3
     selector:
       matchLabels:
         app: myapp
     template:
       metadata:
         labels:
           app: myapp
       spec:
         containers:
         - name: myapp
           image: myapp:latest
           ports:
           - containerPort: 5000
         imagePullSecrets:
         - name: my-registry-key

4. 创建Service对象

   apiVersion: v1
   kind: Service
   metadata:
     name: myapp-service
   spec:
     selector:
       app: myapp
     ports:
     - protocol: TCP
       port: 80
       targetPort: 5000
     type: LoadBalancer

5. 部署Nginx反向代理和负载均衡器

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: nginx
   spec:
     replicas: 2
     selector:
       matchLabels:
         app: nginx
     template:
       metadata:
         labels:
           app: nginx
       spec:
         containers:
         - name: nginx
           image: nginx:latest
           ports:
           - containerPort: 80
           volumeMounts:
           - name: nginx-conf
             mountPath: /etc/nginx/nginx.conf
             subPath: nginx.conf
         volumes:
         - name: nginx-conf
           configMap:
             name: nginx-conf
   ---
   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: nginx-conf
   data:
     nginx.conf: |
       user nginx;
       worker_processes auto;
       error_log /var/log/nginx/error.log;
       pid /var/run/nginx.pid;
       events {
           worker_connections 1024;
       }
       http {
           upstream myapp {
               server myapp-service;
           }
           server {
               listen 80;
               location / {
                   proxy_pass http://myapp;
                   proxy_set_header Host $host;
                   proxy_set_header X-Real-IP $remote_addr;
                   proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
               }
           }
       }

6. 部署Redis

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: redis
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: redis
     template:
       metadata:
         labels:
           app: redis
       spec:
         containers:
         - name: redis
           image: redis:latest
           ports:
           - containerPort: 6379
           volumeMounts:
           - name: redis-data
             mountPath: /data
         volumes:
         - name: redis-data
           emptyDir: {}

7. 使用Kubernetes的Volume功能将Redis数据存储在本地磁盘上

   apiVersion: v1
   kind: Pod
   metadata:
     name: redis-data
   spec:
     containers:
     - name: redis-data
       image: busybox
       command: ["/bin/sh"]
       args: ["-c", "while true; do sleep 3600; done"]
       volumeMounts:
       - name: redis-data
         mountPath: /data
   ---
   apiVersion: v1
   kind: PersistentVolume
   metadata:
     name: redis-data
   spec:
     capacity:
       storage: 1Gi
     accessModes:
     - ReadWriteOnce
     hostPath:
       path: /var/data/redis-data
   ---
   apiVersion: v1
   kind: PersistentVolumeClaim
   metadata:
     name: redis-data
   spec:
     accessModes:
     - ReadWriteOnce
     resources:
       requests:
         storage: 1Gi

8. 使用Kubernetes的ConfigMap功能将Nginx配置文件存储在集群中

9. 运行应用程序并测试

   kubectl apply -f app.yaml
   kubectl apply -f nginx.yaml
   kubectl apply -f redis.yaml
   kubectl apply -f redis-data.yaml
   kubectl apply -f nginx-conf.yaml
   kubectl expose deployment myapp --type=LoadBalancer --name=myapp-service

测试：使用Web浏览器访问Nginx的公共IP地址，应该可以看到Web应用程序的主页。同时，停止一个节点，应用程序将自动迁移到其他节点上，而不会影响其可用性。