Kubernetes文件服务器文件不持久化问题求助

问题现象 #

在DigitalOcean和GKE环境中部署文件服务器后，Pod运行期间/public路径下的文件可正常读写，但Pod被删除或重启后，该目录会恢复到初始状态。已配置PersistentVolumeClaim、Deployment、StorageClass及PersistentVolume，相关配置清单见下文。

配置清单 #

PersistentVolumeClaim #

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: file-claim
  namespace: u-e
spec:
  accessModes:
    - ReadWriteOnce
  volumeMode: Filesystem
  resources:
    requests:
      storage: 5Gi
  storageClassName: "do-block-storage-retain"

Deployment #

apiVersion: apps/v1
kind: Deployment
metadata:
  name: fileapp
  namespace: u-e
  labels:
    app: file
spec:
  replicas: 1
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: file
  template:
    metadata:
      labels:
        app: file
    spec:
      containers:
        - name: fileapp
          image: ghcr.io/myvarlik/file
          ports:
            - containerPort: 8888
          volumeMounts:
            - mountPath: "/public"
              name: filevolume
      volumes:
        - name: filevolume
          persistentVolumeClaim:
            claimName: file-claim
      imagePullSecrets:
        - name: gh-regcred

StorageClass #

allowVolumeExpansion: true
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  creationTimestamp: "2022-09-23T06:31:00Z"
  labels:
    c3.doks.digitalocean.com/component: csi-controller-service
    c3.doks.digitalocean.com/plane: data
    doks.digitalocean.com/managed: "true"
  name: do-block-storage-retain
  resourceVersion: "8814934"
  uid: f711cf4d-efe9-4c63-bd6f-476b684818a8
provisioner: dobs.csi.digitalocean.com
reclaimPolicy: Retain
volumeBindingMode: Immediate

PersistentVolume #

apiVersion: v1
kind: PersistentVolume
metadata:
  annotations:
    pv.kubernetes.io/provisioned-by: dobs.csi.digitalocean.com
    volume.kubernetes.io/provisioner-deletion-secret-name: ""
    volume.kubernetes.io/provisioner-deletion-secret-namespace: ""
  creationTimestamp: "2022-11-13T09:41:49Z"
  finalizers:
  - kubernetes.io/pv-protection
  - external-attacher/dobs-csi-digitalocean-com
  name: pvc-74053a19-97cf-49e3-bdcc-7481c57c82b2
  resourceVersion: "17951524"
  uid: 8a0bb8df-6801-4c44-ab5f-7f065ed22037
spec:
  accessModes:
  - ReadWriteOnce
  capacity:
    storage: 5Gi
  claimRef:
    apiVersion: v1
    kind: PersistentVolumeClaim
    name: file-claim
    namespace: u-e
    resourceVersion: "17950915"
    uid: 74053a19-97cf-49e3-bdcc-7481c57c82b2
  csi:
    driver: dobs.csi.digitalocean.com
    fsType: ext4
    volumeAttributes:
      storage.kubernetes.io/csiProvisionerIdentity: 1663943304029-8081-dobs.csi.digitalocean.com
    volumeHandle: 651836fc-6337-11ed-8354-0a58ac14d348
  persistentVolumeReclaimPolicy: Retain
  storageClassName: do-block-storage-retain
  volumeMode: Filesystem
status:
  phase: Bound

核心原因分析 #

从配置来看，PV/PVC绑定正常、挂载路径配置正确，问题大概率出在容器镜像的初始化逻辑：

• 容器镜像的/public目录自带初始文件，且启动脚本存在**无条件将默认文件复制到/public**的逻辑
• 每次Pod重启时，该脚本会覆盖PVC中存储的用户文件，导致目录回到初始状态

排查步骤 #

1. 检查容器启动脚本
   进入运行中的Pod，查看启动脚本或ENTRYPOINT/CMD逻辑：

   kubectl exec -n u-e <fileapp-pod-name> -- cat /entrypoint.sh  # 替换为实际脚本路径
   kubectl exec -n u-e <fileapp-pod-name> -- ps aux  # 查看进程启动命令
   

   确认是否存在类似cp -r /default-files/* /public/的无条件复制操作。

2. 验证PVC存储正确性
   创建临时测试Pod挂载目标PVC，直接查看存储内容：

   apiVersion: v1
   kind: Pod
   metadata:
     name: test-pvc-mount
     namespace: u-e
   spec:
     containers:
     - name: test-container
       image: busybox:latest
       command: ["sleep", "3600"]
       volumeMounts:
       - name: file-volume
         mountPath: /test-storage
     volumes:
     - name: file-volume
       persistentVolumeClaim:
         claimName: file-claim
   

   执行命令查看PVC内的文件：

   kubectl apply -f test-pod.yaml
   kubectl exec -n u-e test-pvc-mount -- ls -la /test-storage
   

   如果能看到用户之前写入的文件，说明PVC存储正常，问题确在容器初始化逻辑。

解决方案 #

方案1：修改容器启动脚本，避免覆盖已有文件 #

将启动脚本中的无条件复制逻辑，改为仅当/public为空时才初始化：

# 原逻辑
# cp -r /default/public/* /public/

# 修改后逻辑
if [ -z "$(ls -A /public)" ]; then
  cp -r /default/public/* /public/
fi

重新构建镜像并推送，更新Deployment的镜像版本。

方案2：调整挂载路径，绕过容器初始化目录 #

若无法修改容器镜像，可将PVC挂载到/public的子目录，同时修改应用的文件存储路径：
修改Deployment的volumeMounts配置：

volumeMounts:
  - mountPath: "/public/user-files"
    name: filevolume

确保应用配置中，文件存储路径指向/public/user-files。

方案3：确认PV/PVC状态无异常 #

检查PV/PVC的绑定状态及事件：

kubectl get pv,pvc -n u-e
kubectl describe pvc file-claim -n u-e

确保状态为Bound，无挂载错误或权限异常事件。

内容的提问来源于stack exchange，提问作者Muhammed Yahya Varlık