Kubernetes NFS 持久卷权限被拒绝

Question

我在 Kubernetes 中的 POD 上有一个应用程序运行。我想将一些输出文件日志存储在持久存储卷上。

为此，我在 NFS 上创建了一个卷，并通过相关的卷声明将其绑定到 POD。当我尝试写入或访问共享文件夹时，我收到一条 "permission denied" 消息，因为 NFS 显然是只读的。

以下是我用来创建卷的json文件：

{
      "kind": "PersistentVolume",
      "apiVersion": "v1",
      "metadata": {
        "name": "task-pv-test"
      },
      "spec": {
        "capacity": {
          "storage": "10Gi"
        },
        "nfs": {
          "server": <IPAddress>,
          "path": "/export"
        },
        "accessModes": [
          "ReadWriteMany"
        ],
        "persistentVolumeReclaimPolicy": "Delete",
        "storageClassName": "standard"
      }
    }

以下为POD配置文件

kind: Pod
apiVersion: v1
metadata:
    name: volume-test
spec:
    volumes:
        -   name: task-pv-test-storage
            persistentVolumeClaim:
                claimName: task-pv-test-claim
    containers:
        -   name: volume-test
            image: <ImageName>
            volumeMounts:
            -   mountPath: /home
                name: task-pv-test-storage
                readOnly: false

有没有办法更改权限？

更新

这是 PVC 和 NFS 配置：

聚氯乙烯：

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: task-pv-test-claim
spec:
  storageClassName: standard
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 3Gi

NFS 配置

{
  "kind": "Pod",
  "apiVersion": "v1",
  "metadata": {
    "name": "nfs-client-provisioner-557b575fbc-hkzfp",
    "generateName": "nfs-client-provisioner-557b575fbc-",
    "namespace": "default",
    "selfLink": "/api/v1/namespaces/default/pods/nfs-client-provisioner-557b575fbc-hkzfp",
    "uid": "918b1220-423a-11e8-8c62-8aaf7effe4a0",
    "resourceVersion": "27228",
    "creationTimestamp": "2018-04-17T12:26:35Z",
    "labels": {
      "app": "nfs-client-provisioner",
      "pod-template-hash": "1136131967"
    },
    "ownerReferences": [
      {
        "apiVersion": "extensions/v1beta1",
        "kind": "ReplicaSet",
        "name": "nfs-client-provisioner-557b575fbc",
        "uid": "3239b14a-4222-11e8-8c62-8aaf7effe4a0",
        "controller": true,
        "blockOwnerDeletion": true
      }
    ]
  },
  "spec": {
    "volumes": [
      {
        "name": "nfs-client-root",
        "nfs": {
          "server": <IPAddress>,
          "path": "/Kubernetes"
        }
      },
      {
        "name": "nfs-client-provisioner-token-fdd2c",
        "secret": {
          "secretName": "nfs-client-provisioner-token-fdd2c",
          "defaultMode": 420
        }
      }
    ],
    "containers": [
      {
        "name": "nfs-client-provisioner",
        "image": "quay.io/external_storage/nfs-client-provisioner:latest",
        "env": [
          {
            "name": "PROVISIONER_NAME",
            "value": "<IPAddress>/Kubernetes"
          },
          {
            "name": "NFS_SERVER",
            "value": <IPAddress>
          },
          {
            "name": "NFS_PATH",
            "value": "/Kubernetes"
          }
        ],
        "resources": {},
        "volumeMounts": [
          {
            "name": "nfs-client-root",
            "mountPath": "/persistentvolumes"
          },
          {
            "name": "nfs-client-provisioner-token-fdd2c",
            "readOnly": true,
            "mountPath": "/var/run/secrets/kubernetes.io/serviceaccount"
          }
        ],
        "terminationMessagePath": "/dev/termination-log",
        "terminationMessagePolicy": "File",
        "imagePullPolicy": "Always"
      }
    ],
    "restartPolicy": "Always",
    "terminationGracePeriodSeconds": 30,
    "dnsPolicy": "ClusterFirst",
    "serviceAccountName": "nfs-client-provisioner",
    "serviceAccount": "nfs-client-provisioner",
    "nodeName": "det-vkube-s02",
    "securityContext": {},
    "schedulerName": "default-scheduler",
    "tolerations": [
      {
        "key": "node.kubernetes.io/not-ready",
        "operator": "Exists",
        "effect": "NoExecute",
        "tolerationSeconds": 300
      },
      {
        "key": "node.kubernetes.io/unreachable",
        "operator": "Exists",
        "effect": "NoExecute",
        "tolerationSeconds": 300
      }
    ]
  },
  "status": {
    "phase": "Running",
    "hostIP": <IPAddress>,
    "podIP": "<IPAddress>,
    "startTime": "2018-04-17T12:26:35Z",
    "qosClass": "BestEffort"
  }
}

我刚刚从 nfs 配置中删除了一些状态信息以使其更短

Answer 1

你检查过目录的权限了吗？确保所有人都可以获得读取权限。

Answer 2

一个简单的方法是访问 nfs 存储，然后 chmod 777，或者使用卷测试容器中的用户 ID 进行 chown

Answer 3

我对您尝试完成工作的方式有点困惑，无论如何，如果我理解正确，请尝试这个示例：

  volumeClaimTemplates:
  - metadata:
      name: data
      namespace: kube-system
      labels:
        k8s-app: something
        monitoring: something
    spec:
      accessModes:
        - ReadWriteOnce
      resources:
        requests:
          storage: 10Gi

然后也许初始化容器会做一些事情：

initContainers:
        - name: prometheus-init
          image: /something/bash-alpine:1.5
          command:
            - chown
            - -R
            - 65534:65534
            - /data
          volumeMounts:
            - name: data
              mountPath: /data

或者是您错过的 volumeMounts：

volumeMounts:
            - name: config-volume
              mountPath: /etc/config
            - name: data
              mountPath: /data

我最后的评论是要注意容器，我认为你只允许在 /tmp 中写入，还是仅适用于 CoreOS？我得查一下。

Answer 4

如果您为 pod 配置设置了正确的 securityContext，您可以确保使用正确的权限装载该卷。

示例：

apiVersion: v1
kind: Pod
metadata:
  name: demo
spec:
  securityContext:
    fsGroup: 2000 
  volumes:
    - name: task-pv-test-storage
      persistentVolumeClaim:
        claimName: task-pv-test-claim
  containers:
  - name: demo
    image: example-image
    volumeMounts:
    - name: task-pv-test-storage
      mountPath: /data/demo

在上面的示例中，存储将安装在 /data/demo，组 ID 为 2000，由 fsGroup 设置。通过设置 fsGroup 容器的所有进程也将成为补充组 ID 2000 的一部分，因此您应该可以访问已安装的文件。

您可以在此处阅读有关 pod 安全上下文的更多信息：https://kubernetes.io/docs/tasks/configure-pod-container/security-context/

Answer 5

感谢白栋天。例如，如果 pod securityContext 设置为：

securityContext:
  runAsUser: 1000
  fsGroup: 1000

您将通过 ssh 连接到 NFS 主机并且运行

chown 1000:1000 -R /some/nfs/path

如果你不知道 user:group 或许多 pods 会安装它，你可以运行

chmod 777 -R /some/nfs/path

Kubernetes NFS 持久卷权限被拒绝

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