open-nomad/website/pages/docs/job-specification/volume.mdx

---
layout: docs
page_title: volume Stanza - Job Specification
sidebar_title: volume
description: >-
  The "volume" stanza allows the group to specify that it requires a given
  volume from the cluster. Nomad will automatically handle ensuring that the
  volume is available and mounted into the task.
---

# `volume` Stanza

<Placement groups={['job', 'group', 'volume']} />

The `volume` stanza allows the group to specify that it requires a
given volume from the cluster.

The key of the stanza is the name of the volume as it will be exposed
to task configuration.

```hcl
job "docs" {
  group "example" {
    volume "certs" {
      type      = "host"
      source    = "ca-certificates"
      read_only = true
    }
  }
}
```

The Nomad server will ensure that the allocations are only scheduled
on hosts that have a set of volumes that meet the criteria specified
in the `volume` stanzas. These may be [host volumes][host_volume]
configured on the client, or [CSI volumes][csi_volume] dynamically
mounted by [CSI plugins][csi_plugin].

The Nomad client will make the volumes available to tasks according to
the [volume_mount][volume_mount] stanza in the `task` configuration.

## `volume` Parameters

- `type` `(string: "")` - Specifies the type of a given volume. The
  valid volume types are `"host"` and `"csi"`.

- `source` `(string: <required>)` - The name of the volume to
  request. When using `host_volume`'s this should match the published
  name of the host volume. When using `csi` volumes, this should match
  the ID of the registered volume.

- `read_only` `(bool: false)` - Specifies that the group only requires
  read only access to a volume and is used as the default value for
  the `volume_mount -> read_only` configuration. This value is also
  used for validating `host_volume` ACLs and for scheduling when a
  matching `host_volume` requires `read_only` usage.

- `mount_options` - Options for mounting CSI volumes that have the
  `file-system` [attachment mode]. These options override the `mount_options`
  field from [volume registration]. Consult the documentation for your storage
  provider and CSI plugin as to whether these options are required or
  necessary.

  - `fs_type`: file system type (ex. `"ext4"`)
  - `mount_flags`: the flags passed to `mount` (ex. `"ro,noatime"`)


[volume_mount]: /docs/job-specification/volume_mount 'Nomad volume_mount Job Specification'
[host_volume]: /docs/configuration/client#host_volume-stanza
[csi_volume]: /docs/commands/volume/register
[csi_plugin]: /docs/job-specification/csi_plugin
[csi_volume]: /docs/commands/volume/register
[attachment mode]: /docs/commands/volume/register#attachment_mode
[volume registration]: /docs/commands/volume/register#mount_options