instruction: Create a Dockerfile for storage
output: ```dockerfile
  from being used as an inline ephemeral volume.Using an admission webhook
  to restrict how this driver is used.Generic ephemeral volumesFEATURE STATE:
  Kubernetes v1.23 [stable]Generic ephemeral volumes are similar to emptyDir volumes in the
  sense that they provide a per-pod directory for scratch data that is
  usually empty after provisioning. But they may also have additional
  features:Storage can be local or network-attached.Volumes can have a fixed size that Pods are not able to exceed.Volumes may have some initial data, depending on the driver and
  parameters.Typical operations on volumes are supported assuming that the driver
  supports them, including
  snapshotting,
  cloning,
  resizing,
  and storage capacity tracking.Example:kind: Pod
  apiVersion: v1
  metadata:
   name: my-app
  spec:
   containers:
   - name: my-frontend
   image: busybox:1.28
   volumeMounts:
   - mountPath: "/scratch"
   name: scratch-volume
   command: [ "sleep", "1000000" ]
   volumes:
   - name: scratch-volume
   ephemeral:
   volumeClaimTemplate:
   metadata:
   labels:
   type: my-frontend-volume
   spec:
   accessModes: [ "ReadWriteOnce" ]
   storageClassName: "scratch-storage-class"
   resources:
   requests:
   storage: 1Gi
  Lifecycle and PersistentVolumeClaimThe key design idea is that the
  parameters for a volume claim
  are allowed inside a volume source of the Pod. Labels, annotations and
  the whole set of fields for a PersistentVolumeClaim are supported. When such a Pod gets
  created, the ephemeral volume controller then creates an actual PersistentVolumeClaim
  object in the same namespace as the Pod and ensures that the PersistentVolumeClaim
  gets deleted when the Pod gets deleted.That triggers volume binding and/or provisioning, either immediately if
  the StorageClass uses immediate volume binding or when the Pod is
  tentatively scheduled onto a node (WaitForFirstConsumer volume
  binding mode). The latter is recommended for generic ephemeral volumes
  because then the scheduler is free to choose a suitable node for
  the Pod. With immediate binding, the scheduler is forced to select a node that has
  access to the volume once it is available.In terms of resource ownership,
  a Pod that has generic ephemeral storage is the owner of the PersistentVolumeClaim(s)
  that provide that ephemeral storage. When the Pod is deleted,
  the Kubernetes garbage collector deletes the PVC, which then usually
  triggers deletion of the volume because the default reclaim policy of
  storage classes is to delete volumes. You can create quasi-ephemeral local storage
  using a StorageClass with a reclaim policy of retain: the storage outlives the Pod,
  and in this case you need to ensure that volume clean up happens separately.While these PVCs exist, they can be used like any other PVC. In
  particular, they can be referenced as data source in volume cloning or
  snapshotting. The PVC object also holds the current status of the
  volume.PersistentVolumeClaim namingNaming of the automatically created PVCs is deterministic: the name is
  a combination of the Pod name and volume name, with a hyphen (-) in the
  middle. In the example above, the PVC name will be
  my-app-scratch-volume. This deterministic naming makes it easier to
  interact with the PVC because one does not have to search for it once
  the Pod name and volume name are known.The deterministic naming also introduces a potential conflict between different
  Pods (a Pod "pod-a" with volume "scratch" and another Pod with name
  "pod" and volume "a-scratch" both end up with the same PVC name
  "pod-a-scratch") and between Pods and manually created PVCs.Such conflicts are detected: a PVC is only used for an ephemeral
  volume if it was created for the Pod. This check is based on the
  ownership relationship. An existing PVC is not overwritten or
  modified. But this does not resolve the conflict because without the
  right PVC, the Pod cannot start.Caution:Take care when naming Pods and volumes inside the
  same namespace, so that these conflicts can't occur.SecurityUsing generic ephemeral volumes allows users to create PVCs indirectly
  if they can create Pods, even if they do not have permission to create PVCs directly.
  Cluster administrators must be aware of this. If this does not fit their security model,
  they should use an admission webhook
  that rejects objects like Pods that have a generic ephemeral volume.The normal namespace quota for PVCs
  still applies, so even if users are allowed to use this new mechanism, they cannot use
  it to circumvent other policies.What's nextEphemeral volumes managed by kubeletSee local ephemeral storage.CSI ephemeral volumesFor more information on the design, see the
  Ephemeral Inline CSI volumes KEP.For more information on further development of this feature, see the
  enhancement tracking issue #596.Generic ephemeral volumesFor more information on the design, see the
  Generic ephemeral inline volumes KEP.FeedbackWas this page helpful?Yes
  NoThanks for the feedback. If you have a specific, answerable question about how to use Kubernetes, ask it on
  Stack Overflow.
  Open an issue in the GitHub Repository if you want to
  report a problem
  or
  suggest an improvement.Last modified September 14, 2024 at 12:01 AM PST: Update ephemeral-volumes.md (f04a552825)  Create child page
   Create an issue
   Print entire sectionTypes of ephemeral volumesCSI ephemeral volumesCSI driver restrictionsGeneric ephemeral volumesLifecycle and PersistentVolumeClaimPersistentVolumeClaim namingSecurityWhat's nextEphemeral volumes managed by kubeletCSI ephemeral volumesGeneric ephemeral volumes© 2025 The Kubernetes Authors | Documentation Distributed under CC BY 4.0© 2025 The Linux Foundation ®. ```