Mount host path to container according hostPath，when write data to file ，in container can not see updated data

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1

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Cluster information:

package main

import (
    "log"
    "os"
    "os/signal"
    "syscall"
    "time"
)

func main() {
    // 设置日志
    logFile, err := os.OpenFile("app.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
    
    if err != nil {
        log.Fatalf("error opening log file: %v", err)
    }
    defer logFile.Close()

    log.SetOutput(os.Stdout)
    log.Println("应用程序启动")

    // 创建一个 channel 用于接收系统信号
    sigs := make(chan os.Signal, 1)
    // 监听 SIGTERM 和 SIGINT 信号
    signal.Notify(sigs, syscall.SIGTERM, syscall.SIGINT)

    go func() {
        // 等待接收信号
        sig := <-sigs
        log.Printf("收到信号: %s, 正在关闭应用程序...", sig)
        // 模拟清理工作
        time.Sleep(2 * time.Second)
        log.Println("清理工作完成，应用程序已关闭")
        time.Sleep(20 * time.Second)
        os.Exit(0)
    }()

    // 模拟应用程序的主循环
    for {
        log.Println("应用程序正在运行...")
        time.Sleep(1000 * time.Second)
    }
}


cat <<EOF | kubectl apply  -f -
apiVersion: v1
kind: Pod
metadata:
  name: pod
spec:
  containers:
  - name: container
    image: registry.cn-hangzhou.aliyuncs.com/hxpdocker2/term:1.0
    terminationMessagePath: "/dev/my-termination-message"
    terminationMessagePolicy: "File"
    volumeMounts:
    - mountPath: /dev/my-termination-message
      name: volume
    imagePullPolicy: Always
  nodeSelector:
    kubernetes.io/os: linux
  os:
    name: linux
  volumes:
  - name: volume
    hostPath:
      path: /dev/my-termination-message
      type: FileOrCreate
EOF

Kubernetes version:
Cloud being used: (put bare-metal if not on a public cloud)
Installation method:
Host OS:
CNI and version:
CRI and version:

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2

When container starts, It opens up with file descriptor that reads file with with the content of that time. If you update the content of file when container is in running state it will not update or read it.

If you want to see the new content container must be restarted. You can use reload app to automatically restart the pod based on such changes to automate this.