volumeMounts

VolumeMounts are a mechanism in Kubernetes Pod specifications that define how a volume is made available to a container. Each item in the volumeMounts list maps a named volume to a path inside the container’s filesystem. The volume’s name must match a corresponding entry in the pod’s volumes section.

Mounting a volume allows containers to access persistent data, configuration, or shared data. For example, a PersistentVolumeClaim can back a volume to store application state, while a ConfigMap or Secret volume can supply configuration data or sensitive information. When a container starts, the kubelet mounts the specified volume at mountPath with the optional readOnly flag.

Key fields include name, mountPath, and readOnly; optional fields include subPath, subPathExpr, and mountPropagation for advanced scenarios. SubPath lets you mount a subdirectory within the volume, and subPathExpr allows dynamic subpath selection. mountPath is the absolute path inside the container where the volume appears.

Volumes are defined in the pod’s volumes list and can use many backends such as emptyDir, hostPath, configMap, secret, or persistentVolumeClaim. The behavior depends on the volume type; for example, emptyDir is created when a Pod is scheduled and stored on node storage, while a PersistentVolumeClaim binds to a persistent storage backend.

Security and operations considerations include file permissions, user IDs, and potential data sharing between containers. If multiple containers mount the same volume, changes are visible to all; if mounted readOnly, data cannot be written.