Type: disk#

Note

The disk device type is supported for both containers and VMs. It supports hotplugging for both containers and VMs.

Disk devices supply additional storage to instances. For containers, they are essentially mount points inside the instance (either as a bind-mount of an existing file or directory on the host, or, if the source is a block device, a regular mount). Virtual machines share host-side mounts or directories through 9p or virtiofs (if available), or as VirtIO disks for block-based disks.

Disk devices can also be created by attaching a storage volume to an instance.

LXD supports the following additional source types:

Ceph RBD

Mount an existing Ceph RBD device that is externally managed.

LXD can use Ceph to manage an internal file system for the instance, but if you have an existing Ceph RBD that you would like to use for an instance, you can add it with the following command:

lxc config device add <instance_name> <device_name> disk source=ceph:<pool_name>/<volume_name> ceph.user_name=<user_name> ceph.cluster_name=<cluster_name> path=<path_in_instance>
CephFS

Mount an existing CephFS device that is externally managed.

LXD can use Ceph to manage an internal file system for the instance, but if you have an existing Ceph file system that you would like to use for an instance, you can add it with the following command:

lxc config device add <instance_name> <device_name> disk source=cephfs:<fs_name>/<path> ceph.user_name=<user_name> ceph.cluster_name=<cluster_name> path=<path_in_instance>
VM cloud-init

Generate a cloud-init configuration ISO from the cloud-init.vendor-data, cloud-init.user-data and user.meta-data configuration keys (see Instance options) and attach it to the VM, so that cloud-init running inside the VM detects the drive on boot and applies the configuration.

This source type is only applicable to VMs.

To add such a device, use the following command:

lxc config device add <instance_name> <device_name> disk source=cloud-init:config

Device options#

disk devices have the following device options:

Key

Type

Default

Required

Description

boot.priority

integer

-

no

Boot priority for VMs (higher value boots first)

ceph.cluster_name

string

ceph

no

The cluster name of the Ceph cluster (required for Ceph or CephFS sources)

ceph.user_name

string

admin

no

The user name of the Ceph cluster (required for Ceph or CephFS sources)

limits.max

string

-

no

I/O limit in byte/s or IOPS for both read and write (same as setting both limits.read and limits.write)

limits.read

string

-

no

I/O limit in byte/s (various suffixes supported, see Units for storage and network limits) or in IOPS (must be suffixed with iops) - see also Configure I/O limits

limits.write

string

-

no

I/O limit in byte/s (various suffixes supported, see Units for storage and network limits) or in IOPS (must be suffixed with iops) - see also Configure I/O limits

path

string

-

yes

Path inside the instance where the disk will be mounted (only for containers)

pool

string

-

no

The storage pool to which the disk device belongs (only applicable for storage volumes managed by LXD)

propagation

string

-

no

Controls how a bind-mount is shared between the instance and the host (can be one of private, the default, or shared, slave, unbindable, rshared, rslave, runbindable, rprivate; see the Linux Kernel shared subtree documentation for a full explanation)

raw.mount.options

string

-

no

File system specific mount options

readonly

bool

false

no

Controls whether to make the mount read-only

recursive

bool

false

no

Controls whether to recursively mount the source path

required

bool

true

no

Controls whether to fail if the source doesn’t exist

shift

bool

false

no

Sets up a shifting overlay to translate the source UID/GID to match the instance (only for containers)

size

string

-

no

Disk size in bytes (various suffixes supported, see Units for storage and network limits) - only supported for the rootfs (/)

size.state

string

-

no

Same as size, but applies to the file-system volume used for saving runtime state in VMs

source

string

-

yes

Path on the host, either to a file/directory or to a block device