PersistentVolumes

PersistentVolumes represent both administrator-created and automatically provisioned storage. They contain data about the underlying storage medium, e.g. a disk or network share. The lifecycle of a PV is independent from a pod's, providing a basis for storage in stateful applications.

Pods make PersistentVolumeClaims for PVs, which are attached to pods via the host node's Kubelet, which maps it into the pod via a bind mount.

apiVersion: v1
kind: PersistentVolume
metadata:
    name: my-pv
spec:
    capacity:
        storage: 42Gi
    accessModes:
      - ReadWriteMany
    nfs:
        server: 10.100.118.247
        path: /export

Volume types

From Volumes

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configMap can be used to mount keys of ConfigMaps.
secret can be used to mount keys of Secrets.

Existing volumes can be imported mounted into pods, though their lifecycles won't be managed by the cluster:

cephfs mounts existing CephFS volumes.
fc mounts fibre channel volumes.
glusterfs allow replicated, multi-writer access to a volume.
iscsi mounts existing iSCSI volumes.
nfs mounts an external Network File System share.

Useful for testing, or for configurations in which the pod needs to be able to manipulate host configuration:

emptyDir is useful for storing transient data, and its lifetime is tied to the pod.
hostPath is Node-specific. Note the type field, which allows sharing sockets.

Cloud-specific volume types may be available based on the environment in which the cluster is running:

awsElasticBlockStore for EBS volumes
azureDisk for Azure Disks.
azureFiles for Azure Files shares.
gcePersistentDisk for GCP persistent disks (Private).

flexVolume is a pre-CSI mechanism for extension.

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Volume types