You can attach block storage to instances from the dashboard on the Volumes page. Click the action next to the volume you want to attach.
To perform this action from command line, run the following command:
$ nova volume-attach <server> <volume> <device>
You can also specify block device mapping at instance boot time through the nova command-line client with this option set:
--block-device-mapping <dev-name=mapping>
The block device mapping format is
<dev-name>=<id>:<type>:<size(GB)>:<delete-on-terminate>,
where:
- dev-name
A device name where the volume is attached in the system at
/dev/dev_name- id
The ID of the volume to boot from, as shown in the output of
nova volume-list- type
Either
snap, which means that the volume was created from a snapshot, or anything other thansnap(a blank string is valid). In the preceding example, the volume was not created from a snapshot, so we leave this field blank in our following example.- size (GB)
The size of the volume in gigabytes. It is safe to leave this blank and have the Compute Service infer the size.
- delete-on-terminate
A boolean to indicate whether the volume should be deleted when the instance is terminated. True can be specified as
Trueor1. False can be specified asFalseor0.
The following command will boot a new instance and attach a volume
at the same time. The volume of ID 13 will be attached as
/dev/vdc. It is not a snapshot, does not specify a size, and
will not be deleted when the instance is terminated:
$ nova boot --image 4042220e-4f5e-4398-9054-39fbd75a5dd7 \
--flavor 2 --key-name mykey --block-device-mapping vdc=13:::0 \
boot-with-vol-testIf you have previously prepared block storage with a bootable file
system image, it is even possible to boot from persistent block storage.
The following command boots an image from the specified volume. It is
similar to the previous command, but the image is omitted and the volume
is now attached as /dev/vda:
$ nova boot --flavor 2 --key-name mykey \
--block-device-mapping vda=13:::0 boot-from-vol-testRead more detailed instructions for launching an instance from a bootable volume in the OpenStack End User Guide.
To boot normally from an image and attach block storage, map to a device other than vda. You can find instructions for launching an instance and attaching a volume to the instance and for copying the image to the attached volume in the OpenStack End User Guide.
