Hetzner Cloud Volume
Provisions a Hetzner Cloud block storage volume with an optional server attachment. Volumes persist independently of any server, making them the standard mechanism for data that must survive server replacement — databases, application state, and uploaded files. Size can be increased online after creation but can never be decreased.
What Gets Created
- Block Storage Volume — an
hcloud_volumeresource with the specified size, location, optional filesystem format (ext4 or xfs), labels computed from resource metadata, and optional delete protection. - Volume Attachment (when
serverIdis set) — anhcloud_volume_attachmentresource that attaches the volume to the specified server with optional automount. Created only when theserverIdfield is present. The volume and server must be in the same location.
Prerequisites
- Hetzner Cloud API token configured via environment variable (
HCLOUD_TOKEN) or OpenMCF provider config - A server in the same location if attaching the volume via
serverId— either pre-existing or managed as aHetznerCloudServercomponent
Quick Start
Create a file volume.yaml:
apiVersion: hetzner-cloud.openmcf.org/v1
kind: HetznerCloudVolume
metadata:
name: my-volume
labels:
openmcf.org/provisioner: pulumi
pulumi.openmcf.org/organization: my-org
pulumi.openmcf.org/project: my-project
pulumi.openmcf.org/stack.name: dev.HetznerCloudVolume.my-volume
spec:
size: 10
location: fsn1
Deploy:
openmcf apply -f volume.yaml
This creates a 10 GB raw (unformatted) volume in Falkenstein, unattached to any server.
Configuration Reference
Required Fields
| Field | Type | Description | Validation |
|---|---|---|---|
size | int | Volume size in GB. Can be increased after creation but never decreased — the Hetzner Cloud API rejects size reductions. | gte: 10, lte: 10240 |
location | string | Hetzner Cloud location where the volume is stored. Known locations: fsn1, nbg1, hel1, ash, hil, sin. The volume can only be attached to servers in the same location. Changing this forces volume replacement (data loss). | min_len: 1 |
Optional Fields
| Field | Type | Default | Description |
|---|---|---|---|
format | enum | unspecified (raw) | Filesystem format applied at creation time. Valid values: ext4, xfs. When unspecified, the volume is created as a raw block device that must be formatted manually. This is a create-time-only setting — changing it after creation has no effect. |
serverId | StringValueOrRef | unset | Server to attach the volume to. Accepts a literal Hetzner Cloud server ID (as a string) or a reference to a HetznerCloudServer resource via valueFrom. The server must be in the same location. When set, creates an hcloud_volume_attachment resource. |
automount | bool | false | Automatically mount the volume on the server after attaching. Only meaningful when serverId is set. This is a create-time-only setting. |
deleteProtection | bool | false | Prevent accidental deletion of the volume via the Hetzner Cloud API. Must be disabled before the volume can be deleted. |
Examples
Unattached Volume with ext4
A formatted volume created without a server attachment. Useful for pre-provisioning storage that will be attached to a server later.
apiVersion: hetzner-cloud.openmcf.org/v1
kind: HetznerCloudVolume
metadata:
name: app-data
org: acme-corp
env: staging
labels:
openmcf.org/provisioner: pulumi
pulumi.openmcf.org/organization: acme-corp
pulumi.openmcf.org/project: storage
pulumi.openmcf.org/stack.name: staging.HetznerCloudVolume.app-data
spec:
size: 50
location: fsn1
format: ext4
Volume Attached to a Server
A volume attached to a server with automount enabled. The serverId uses a valueFrom reference to a HetznerCloudServer component, ensuring the server is created before the volume attachment.
apiVersion: hetzner-cloud.openmcf.org/v1
kind: HetznerCloudVolume
metadata:
name: db-data
org: acme-corp
env: production
labels:
openmcf.org/provisioner: pulumi
pulumi.openmcf.org/organization: acme-corp
pulumi.openmcf.org/project: databases
pulumi.openmcf.org/stack.name: production.HetznerCloudVolume.db-data
spec:
size: 100
location: fsn1
format: ext4
serverId:
valueFrom:
kind: HetznerCloudServer
name: db-primary
fieldPath: status.outputs.server_id
automount: true
Production Volume with Protection
A large XFS volume for high-throughput workloads with delete protection enabled. XFS is suited for large sequential writes — log aggregation, media storage, and backup repositories.
apiVersion: hetzner-cloud.openmcf.org/v1
kind: HetznerCloudVolume
metadata:
name: media-storage
org: acme-corp
env: production
labels:
openmcf.org/provisioner: pulumi
pulumi.openmcf.org/organization: acme-corp
pulumi.openmcf.org/project: media-platform
pulumi.openmcf.org/stack.name: production.HetznerCloudVolume.media-storage
role: media
spec:
size: 500
location: fsn1
format: xfs
serverId:
valueFrom:
kind: HetznerCloudServer
name: media-processor
fieldPath: status.outputs.server_id
automount: true
deleteProtection: true
Stack Outputs
| Output | Type | Description |
|---|---|---|
volume_id | string | Hetzner Cloud numeric ID of the created volume. Available for external reference by scripts or monitoring systems. |
linux_device | string | The Linux device path for the volume on the attached server (e.g., /dev/disk/by-id/scsi-0HC_Volume_12345678). Stable across reboots. Empty if the volume is not attached. Suitable for /etc/fstab entries. |
Related Components
- HetznerCloudServer — Compute instance the volume attaches to, referenced via
serverId
Next article
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