---
layout: docs
page_title: 'Commands: volume create'
description: |
  Create volumes with CSI plugins.
---

# Command: volume create

The `volume create` command creates external storage volumes with Nomad's
[Container Storage Interface (CSI)][csi] support. Only CSI plugins that
implement the [Controller][csi_plugins_internals] interface support this
command. The volume will also be [registered] when it is successfully created.

## Usage

```plaintext
nomad volume create [options] [file]
```

The `volume create` command requires a single argument, specifying the path to
a file containing a valid [volume specification][volume_specification]. This
file will be read and the volume will be submitted to Nomad for scheduling. If
the supplied path is "-", the volume file is read from STDIN. Otherwise it is
read from the file at the supplied path.

When ACLs are enabled, this command requires a token with the
`csi-write-volume` capability for the volume's namespace.

## General Options

@include 'general_options.mdx'

## Volume Specification

The file may be provided as either HCL or JSON. An example HCL configuration:

```hcl
id           = "ebs_prod_db1"
namespace    = "default"
name         = "database"
type         = "csi"
plugin_id    = "ebs-prod"
snapshot_id  = "snap-12345" # or clone_id, see below
capacity_max = "200G"
capacity_min = "100G"

capability {
  access_mode     = "single-node-reader-only"
  attachment_mode = "file-system"
}

capability {
  access_mode     = "single-node-writer"
  attachment_mode = "file-system"
}

mount_options {
  fs_type     = "ext4"
  mount_flags = ["noatime"]
}

topology_request {
  required {
    topology { segments { "rack" = "R2" } }
    topology { segments { "rack" = "R1", "zone" = "us-east-1a"} }
  }
  preferred {
    topology { segments { "rack" = "R1", "zone" = "us-east-1a"} }
  }
}

secrets {
  example_secret = "xyzzy"
}

parameters {
  skuname = "Premium_LRS"
}
```

## Volume Specification Parameters

- `id` `(string: <required>)` - The unique ID of the volume. This is how the
  [`volume.source`][csi_volume_source] field in a job specification will refer
  to the volume.

- `namespace` `(string: <optional>)` - The namespace of the volume. This field
  overrides the namespace provided by the `-namespace` flag or `NOMAD_NAMESPACE`
  environment variable. Defaults to `"default"` if unset.

- `name` `(string: <required>)` - The display name of the volume. This field
  may be used by the external storage provider to tag the volume.

- `type` `(string: <required>)` - The type of volume. Currently only `"csi"`
  is supported.

- `plugin_id` `(string: <required>)` - The ID of the [CSI plugin][csi_plugin]
  that manages this volume.

- `snapshot_id` `(string: <optional>)` - If the storage provider supports
  snapshots, the external ID of the snapshot to restore when creating this
  volume. If omitted, the volume will be created from scratch. The
  `snapshot_id` cannot be set if the `clone_id` field is set.

- `clone_id` `(string: <optional>)` - If the storage provider supports
  cloning, the external ID of the volume to clone when creating this
  volume. If omitted, the volume will be created from scratch. The
  `clone_id` cannot be set if the `snapshot_id` field is set.

- `capacity_min` `(string: <optional>)` - Option for requesting a
  minimum capacity, in bytes. The capacity of a volume may be the
  physical size of a disk, or a quota, depending on the storage
  provider. The specific size of the resulting volume will be
  somewhere between `capacity_min` and `capacity_max`; the exact
  behavior is up to the storage provider. If you want to specify an
  exact size, you should set `capacity_min` and `capacity_max` to the
  same value. Accepts human-friendly suffixes such as `"100GiB"`. This
  field may not be supported by all storage providers.

- `capacity_max` `(string: <optional>)` - Option for requesting a
  maximum capacity, in bytes. The capacity of a volume may be the
  physical size of a disk, or a quota, depending on the storage
  provider. The specific size of the resulting volume will be
  somewhere between `capacity_min` and `capacity_max`; the exact
  behavior is up to the storage provider. If you want to specify an
  exact size, you should set `capacity_min` and `capacity_max` to the
  same value. Accepts human-friendly suffixes such as `"100GiB"`. This
  field may not be supported by all storage providers.

- `capability` `(Capability: <required>)` - Option for validating the
  capability of a volume. You must provide at least one `capability` block, and
  you must provide a block for each capability you intend to use in a job's
  [`volume`] block. Each `capability` block must have the following fields:

  - `access_mode` `(string: <required>)` - Defines whether a volume should be
    available concurrently. Can be one of `"single-node-reader-only"`,
    `"single-node-writer"`, `"multi-node-reader-only"`,
    `"multi-node-single-writer"`, or `"multi-node-multi-writer"`. Most CSI
    plugins support only single-node modes. Consult the documentation of the
    storage provider and CSI plugin.

  - `attachment_mode` `(string: <required>)` - The storage API that will be used
    by the volume. Most storage providers will support `"file-system"`, to mount
    volumes using the CSI filesystem API. Some storage providers will support
    `"block-device"`, which will mount the volume with the CSI block device API
    within the container.

- `mount_options` - Options for mounting `file-system` volumes that don't
  already have a pre-formatted file system. This block will be validated
  during volume creation against the `capability` field. The `mount_options`
  provided in a job specification's [`volume`] block will override this
  block. Consult the documentation for your storage provider and CSI plugin as
  to whether these options are required or necessary.

  - `fs_type` `(string <optional>)` - File system type (ex. `"ext4"`)
  - `mount_flags` `([]string: <optional>)` - The flags passed to `mount`
    (ex. `["ro", "noatime"]`)

- `topology_request` <code>([TopologyRequest](#topology_request-parameters): nil)</code> -
  Specify locations (region, zone, rack, etc.)  where the provisioned
  volume must be accessible from. Consult the documentation for your
  storage provider and CSI plugin as to whether it supports defining
  topology and what values it expects for topology
  segments. Specifying topology segments that aren't supported by the
  storage provider may return an error or may be silently removed by
  the plugin.

- `secrets` <code>(map<string|string>:nil)</code> - An optional
  key-value map of strings used as credentials for publishing and
  unpublishing volumes.

- `parameters` <code>(map<string|string>:nil)</code> - An optional
  key-value map of strings passed directly to the CSI plugin to
  configure the volume. The details of these parameters are specific
  to each storage provider, so please see the specific plugin
  documentation for more information.

### `topology_request` Parameters

For the `topology_request` field, you may specify a list of either
`required` or `preferred` topologies (or both). The `required`
topologies indicate that the volume must be created in a location
accessible from at least one of the listed topologies. The `preferred`
topologies indicate that you would prefer the storage provider to
create the volume in one of the provided topologies.

Each topology listed has a single field:

- `segments` `(map[string]string)` - A map of location types to their
 values. The specific fields required are defined by the CSI
 plugin. For example, a plugin might require defining both a rack and
 a zone: `segments {rack = "R2", zone = "us-east-1a"}`.

For example:

```hcl
topology_request {
  required {
    topology { segments { "rack" = "R1", "zone" = "us-east-1a" } }
    topology { segments { "rack" = "R2", "zone" = "us-east-1a" } }
  }
  preferred {
    topology { segments { "rack" = "R1", "zone" = "us-east-1a"} }
  }
}
```

This configuration indicates you require the volume to be created
within racks `R1` or `R2`, but that you prefer the volume to be
created within `R1`.

### Unused Fields

Note that several fields used in the [`volume register`] command are set
automatically by the plugin when `volume create` is successful. You should not
set the `external_id` or `context` fields described on that page.

[csi]: https://github.com/container-storage-interface/spec
[csi_plugins_internals]: /docs/internals/plugins/csi#csi-plugins
[volume_specification]: #volume-specification
[csi_plugin]: /docs/job-specification/csi_plugin
[csi_volume_source]: /docs/job-specification/volume#source
[registered]: /docs/commands/volume/register
[`volume register`]: /docs/commands/volume/register
[`volume`]: /docs/job-specification/volume
