Read-only file system in hostpath.so unable to mount volume

Question

When I am giving hostpath it is showing that it is read-only file system since I am new to kubernetes I didn't find any other way please let me know such that is there any other way of implementation of volumes and I am doing this on GKE here is my yaml code

apiVersion: apps/v1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "10"
  creationTimestamp: "2019-11-22T10:52:16Z"
  generation: 17
  labels:
    app: dataset
  name: dataset
  namespace: default
  resourceVersion: "283767"
  selfLink: /apis/apps/v1/namespaces/default/deployments/dataset
  uid: 26111fe8-0d16-11ea-a66e-42010aa00042
spec:
  progressDeadlineSeconds: 600
  replicas: 2
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app: dataset
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: dataset
    spec:
      containers:
      - env:
        - name: RABBIT_MQ_HOST
          valueFrom:
            configMapKeyRef:
              key: RABBIT_MQ_HOST
              name: dataset-config
        - name: RABBIT_MQ_USER
          valueFrom:
            configMapKeyRef:
              key: RABBIT_MQ_USER
              name: dataset-config
        - name: RABBIT_MQ_PASSWORD
          valueFrom:
            configMapKeyRef:
              key: RABBIT_MQ_PASSWORD
              name: dataset-config
        - name: DATASET_DB_HOST
          valueFrom:
            configMapKeyRef:
              key: DATASET_DB_HOST
              name: dataset-config
        - name: DATASET_DB_NAME
          valueFrom:
            configMapKeyRef:
              key: DATASET_DB_NAME
              name: dataset-config
        - name: LICENSE_SERVER
          valueFrom:
            configMapKeyRef:
              key: LICENSE_SERVER
              name: dataset-config
        - name: DATASET_THUMBNAIL_SIZE
          valueFrom:
            configMapKeyRef:
              key: DATASET_THUMBNAIL_SIZE
              name: dataset-config
        - name: GATEWAY_URL
          valueFrom:
            configMapKeyRef:
              key: GATEWAY_URL
              name: dataset-config
        - name: DEFAULT_DATASOURCE_ID
          valueFrom:
            configMapKeyRef:
              key: DEFAULT_DATASOURCE_ID
              name: dataset-config
        - name: RABBIT_MQ_QUEUE_NAME
          valueFrom:
            configMapKeyRef:
              key: RABBIT_MQ_QUEUE_NAME
              name: dataset-config
        - name: RABBIT_MQ_PATTERN
          valueFrom:
            configMapKeyRef:
              key: RABBIT_MQ_PATTERN
              name: dataset-config
        image: gcr.io/gcr-testing-258008/dataset@sha256:8416ec9b023d4a4587a511b855c2735b25a16dbb1a15531d8974d0ef89ad3d73
        imagePullPolicy: IfNotPresent
        name: dataset-sha256
        resources: {}
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
        volumeMounts:
        - mountPath: ./data/uploads
          name: dataset-volume-uploads
        - mountPath: ./data/thumbnails
          name: dataset-volume-thumbnails
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      terminationGracePeriodSeconds: 30
      volumes:
      - hostPath:
          path: /build/uploads
          type: ""
        name: dataset-volume-uploads
      - hostPath:
          path: /build/thumbnails
          type: ""
        name: dataset-volume-thumbnails
status:
  availableReplicas: 2
  conditions:
  - lastTransitionTime: "2019-11-23T07:19:13Z"
    lastUpdateTime: "2019-11-23T07:19:13Z"
    message: Deployment has minimum availability.
    reason: MinimumReplicasAvailable
    status: "True"
    type: Available
  - lastTransitionTime: "2019-11-23T06:31:03Z"
    lastUpdateTime: "2019-11-23T07:24:42Z"
    message: ReplicaSet "dataset-75b46f868f" is progressing.
    reason: ReplicaSetUpdated
    status: "True"
    type: Progressing
  observedGeneration: 17
  readyReplicas: 2
  replicas: 3
  unavailableReplicas: 1
  updatedReplicas: 1

Here is my description of pod

    Path:          /build/uploads
    HostPathType:  
  dataset-volume-thumbnails:
    Type:          HostPath (bare host directory volume)
    Path:          /build/thumbnails
    HostPathType:  
  default-token-x2wmw:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-x2wmw
    Optional:    false
QoS Class:       Burstable
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s
                 node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type     Reason     Age                From                                              Message
  ----     ------     ----               ----                                              -------
  Normal   Scheduled  96s                default-scheduler                                 Successfully assigned default/dataset-75b46f868f-wffm7 to gke-teric-ai-default-pool-41929025-fxnx
  Warning  BackOff    15s (x6 over 93s)  kubelet, gke-teric-ai-default-pool-41929025-fxnx  Back-off restarting failed container
  Normal   Pulled     2s (x5 over 95s)   kubelet, gke-teric-ai-default-pool-41929025-fxnx  Container image "gcr.io/gcr-testing-258008/dataset@sha256:8416ec9b023d4a4587a511b855c2735b25a16dbb1a15531d8974d0ef89ad3d73" already present on machine
  Normal   Created    2s (x5 over 95s)   kubelet, gke-teric-ai-default-pool-41929025-fxnx  Created container
  Warning  Failed     1s (x5 over 95s)   kubelet, gke-teric-ai-default-pool-41929025-fxnx  Error: failed to start container "dataset-sha256": Error response from daemon: error while creating mount source path '/build/uploads': mkdir /build/uploads: read-only file system

So here is the problem even though I am giving chmod permissions dynamically it is not allowing to do write operations.i have tried persistent volumes it is also not worked so please tell me know in which way I have to mount volumes.

Answer 1

• First of all, do not use hostPath, go for persistence storage
• I would use StatefulSets instead of Deployment if you need to store some data.

I was able to create both hostPath on my GKE instance manually as root user.

I guess you have to specify type for hostPath to create request directory if it doesn't exist. type: DirectoryOrCreate you can read more about hostPath and available type values. Moreover, if you are using hostPath permissions of your user inside a container must match ownership on the node so it makes it more complicated, of course, you could run it as root, but it is not recommended way.

To sum it up, just use persistent storage provisioned by google. If you encounter problems with permissions you probably need init contaner to change permission or you have to set proper fsGroup for your container.