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Launch an instance from a volume
You can boot instances from a volume instead of an image.
To complete these tasks, use these parameters on the nova boot command:
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| Task | nova boot parameter | Information |
|---|---|---|
| Boot an instance from an image and attach a non-bootable volume. | --block-device |
Boot_instance_from_image_and_attach_non-bootable_volume |
| Create a volume from an image and boot an instance from that volume. | --block-device |
Create_volume_from_image_and_boot_instance |
| Boot from an existing source image, volume, or snapshot. | --block-device |
Create_volume_from_image_and_boot_instance |
| Attach a swap disk to an instance. | --swap |
Attach_swap_or_ephemeral_disk_to_an_instance |
| Attach an ephemeral disk to an instance. | --ephemeral |
Attach_swap_or_ephemeral_disk_to_an_instance |
Note
To attach a volume to a running instance, refer to the Cinder documentation
<cli/cli-manage-volumes.html#attach-a-volume-to-an-instance>.
Note
The maximum limit on the number of disk devices allowed to attach to
a single server is configurable with the option :oslo.configcompute.max_disk_devices_to_attach.
Boot instance from image and attach non-bootable volume
Create a non-bootable volume and attach that volume to an instance that you boot from an image.
To create a non-bootable volume, do not create it from an image. The volume must be entirely empty with no partition table and no file system.
Create a non-bootable volume.
$ openstack volume create --size 8 my-volume +---------------------+--------------------------------------+ | Field | Value | +---------------------+--------------------------------------+ | attachments | [] | | availability_zone | nova | | bootable | false | | consistencygroup_id | None | | created_at | 2016-11-25T10:37:08.850997 | | description | None | | encrypted | False | | id | b8f7bbec-6274-4cd7-90e7-60916a5e75d4 | | migration_status | None | | multiattach | False | | name | my-volume | | properties | | | replication_status | disabled | | size | 8 | | snapshot_id | None | | source_volid | None | | status | creating | | type | None | | updated_at | None | | user_id | 0678735e449149b0a42076e12dd54e28 | +---------------------+--------------------------------------+List volumes.
$ openstack volume list +--------------------------------------+--------------+-----------+------+-------------+ | ID | Name | Status | Size | Attached to | +--------------------------------------+--------------+-----------+------+-------------+ | b8f7bbec-6274-4cd7-90e7-60916a5e75d4 | my-volume | available | 8 | | +--------------------------------------+--------------+-----------+------+-------------+Boot an instance from an image and attach the empty volume to the instance.
$ nova boot --flavor 2 --image 98901246-af91-43d8-b5e6-a4506aa8f369 \ --block-device source=volume,id=d620d971-b160-4c4e-8652-2513d74e2080,dest=volume,shutdown=preserve \ myInstanceWithVolume +--------------------------------------+--------------------------------------------+ | Property | Value | +--------------------------------------+--------------------------------------------+ | OS-DCF:diskConfig | MANUAL | | OS-EXT-AZ:availability_zone | nova | | OS-EXT-SRV-ATTR:host | - | | OS-EXT-SRV-ATTR:hypervisor_hostname | - | | OS-EXT-SRV-ATTR:instance_name | instance-00000004 | | OS-EXT-STS:power_state | 0 | | OS-EXT-STS:task_state | scheduling | | OS-EXT-STS:vm_state | building | | OS-SRV-USG:launched_at | - | | OS-SRV-USG:terminated_at | - | | accessIPv4 | | | accessIPv6 | | | adminPass | ZaiYeC8iucgU | | config_drive | | | created | 2014-05-09T16:34:50Z | | flavor | m1.small (2) | | hostId | | | id | 1e1797f3-1662-49ff-ae8c-a77e82ee1571 | | image | cirros-0.3.5-x86_64-uec (98901246-af91-... | | key_name | - | | metadata | {} | | name | myInstanceWithVolume | | os-extended-volumes:volumes_attached | [{"id": "d620d971-b160-4c4e-8652-2513d7... | | progress | 0 | | security_groups | default | | status | BUILD | | tenant_id | ccef9e62b1e645df98728fb2b3076f27 | | updated | 2014-05-09T16:34:51Z | | user_id | fef060ae7bfd4024b3edb97dff59017a | +--------------------------------------+--------------------------------------------+
Create volume from image and boot instance
You can create a volume from an existing image, volume, or snapshot. This procedure shows you how to create a volume from an image, and use the volume to boot an instance.
List the available images.
$ openstack image list +-----------------+---------------------------------+--------+ | ID | Name | Status | +-----------------+---------------------------------+--------+ | 484e05af-a14... | Fedora-x86_64-20-20131211.1-sda | active | | 98901246-af9... | cirros-0.3.5-x86_64-uec | active | | b6e95589-7eb... | cirros-0.3.5-x86_64-uec-kernel | active | | c90893ea-e73... | cirros-0.3.5-x86_64-uec-ramdisk | active | +-----------------+---------------------------------+--------+Note the ID of the image that you want to use to create a volume.
If you want to create a volume to a specific storage backend, you need to use an image which has cinder_img_volume_type property. In this case, a new volume will be created as storage_backend1 volume type.
$ openstack image show 98901246-af9d-4b61-bea8-09cc6dc41829 +------------------+------------------------------------------------------+ | Field | Value | +------------------+------------------------------------------------------+ | checksum | ee1eca47dc88f4879d8a229cc70a07c6 | | container_format | bare | | created_at | 2016-10-08T14:59:05Z | | disk_format | qcow2 | | file | /v2/images/9fef3b2d-c35d-4b61-bea8-09cc6dc41829/file | | id | 98901246-af9d-4b61-bea8-09cc6dc41829 | | min_disk | 0 | | min_ram | 0 | | name | cirros-0.3.5-x86_64-uec | | owner | 8d8ef3cdf2b54c25831cbb409ad9ae86 | | protected | False | | schema | /v2/schemas/image | | size | 13287936 | | status | active | | tags | | | updated_at | 2016-10-19T09:12:52Z | | virtual_size | None | | visibility | public | +------------------+------------------------------------------------------+List the available flavors.
$ openstack flavor list +-----+-----------+-------+------+-----------+-------+-----------+ | ID | Name | RAM | Disk | Ephemeral | VCPUs | Is_Public | +-----+-----------+-------+------+-----------+-------+-----------+ | 1 | m1.tiny | 512 | 1 | 0 | 1 | True | | 2 | m1.small | 2048 | 20 | 0 | 1 | True | | 3 | m1.medium | 4096 | 40 | 0 | 2 | True | | 4 | m1.large | 8192 | 80 | 0 | 4 | True | | 5 | m1.xlarge | 16384 | 160 | 0 | 8 | True | +-----+-----------+-------+------+-----------+-------+-----------+Note the ID of the flavor that you want to use to create a volume.
To create a bootable volume from an image and launch an instance from this volume, use the
--block-deviceparameter with thenova bootcommand.For example:
$ nova boot --flavor FLAVOR --block-device \ source=SOURCE,id=ID,dest=DEST,size=SIZE,shutdown=PRESERVE,bootindex=INDEX \ NAMEThe parameters are:
--flavorThe flavor ID or name.--block-devicesource=SOURCE,id=ID,dest=DEST,size=SIZE,shutdown=PRESERVE,bootindex=INDEX- source=SOURCE
-
The type of object used to create the block device. Valid values are
volume,snapshot,image, andblank. - id=ID
-
The ID of the source object.
- dest=DEST
-
The type of the target virtual device. Valid values are
volumeandlocal. - size=SIZE
-
The size of the volume that is created.
- shutdown={preserve|remove}
-
What to do with the volume when the instance is deleted.
preservedoes not delete the volume.removedeletes the volume. - bootindex=INDEX
-
Orders the boot disks. Use
0to boot from this volume.
NAME. The name for the server.
See the nova boot command documentation and
block-device-mappingfor more details on these parameters.Note
As of the Stein release, the
openstack server createcommand does not support creating a volume-backed server from a source image like thenova bootcommand. The next steps will show how to create a bootable volume from an image and then create a server from that boot volume using theopenstack server createcommand.Create a bootable volume from an image. Cinder makes a volume bootable when
--imageparameter is passed.$ openstack volume create --image IMAGE_ID --size SIZE_IN_GB bootable_volumeNote
A bootable encrypted volume can also be created by adding the --type ENCRYPTED_VOLUME_TYPE parameter to the volume create command:
$ openstack volume create --type ENCRYPTED_VOLUME_TYPE --image IMAGE_ID --size SIZE_IN_GB bootable_volume +---------------------+--------------------------------------+ | Field | Value | +---------------------+--------------------------------------+ | attachments | [] | | availability_zone | nova | | bootable | false | | consistencygroup_id | None | | created_at | 2017-06-13T18:59:57.626872 | | description | None | | encrypted | True | | id | ded57a86-5b51-43ab-b70e-9bc0f91ef4ab | | multiattach | False | | name | bootable_volume | | properties | | | replication_status | None | | size | 1 | | snapshot_id | None | | source_volid | None | | status | creating | | type | LUKS | | updated_at | None | | user_id | 459ae34ffcd94edab0c128ed616bb19f | +---------------------+--------------------------------------+This requires an encrypted volume type, which must be created ahead of time by an admin. Refer to
admin/manage-volumes.html#create-an-encrypted-volume-type. in the OpenStack Horizon Administration Guide.Create a VM from previously created bootable volume. The volume is not deleted when the instance is terminated.
Note
The example here uses the
--volumeoption for simplicity. The--block-device-mappingoption could also be used for more granular control over the parameters. See the openstack server create documentation for details.$ openstack server create --flavor 2 --volume VOLUME_ID myInstanceFromVolume +--------------------------------------+--------------------------------+ | Field | Value | +--------------------------------------+--------------------------------+ | OS-EXT-STS:task_state | scheduling | | image | Attempt to boot from volume | | | - no image supplied | | OS-EXT-STS:vm_state | building | | OS-EXT-SRV-ATTR:instance_name | instance-00000003 | | OS-SRV-USG:launched_at | None | | flavor | m1.small | | id | 2e65c854-dba9-4f68-8f08-fe3... | | security_groups | [{u'name': u'default'}] | | user_id | 352b37f5c89144d4ad053413926... | | OS-DCF:diskConfig | MANUAL | | accessIPv4 | | | accessIPv6 | | | progress | 0 | | OS-EXT-STS:power_state | 0 | | OS-EXT-AZ:availability_zone | nova | | config_drive | | | status | BUILD | | updated | 2014-02-02T13:29:54Z | | hostId | | | OS-EXT-SRV-ATTR:host | None | | OS-SRV-USG:terminated_at | None | | key_name | None | | OS-EXT-SRV-ATTR:hypervisor_hostname | None | | name | myInstanceFromVolume | | adminPass | TzjqyGsRcJo9 | | tenant_id | f7ac731cc11f40efbc03a9f9e1d... | | created | 2014-02-02T13:29:53Z | | os-extended-volumes:volumes_attached | [{"id": "2fff50ab..."}] | | metadata | {} | +--------------------------------------+--------------------------------+List volumes to see the bootable volume and its attached
myInstanceFromVolumeinstance.$ openstack volume list +---------------------+-----------------+--------+------+---------------------------------+ | ID | Name | Status | Size | Attached to | +---------------------+-----------------+--------+------+---------------------------------+ | c612f739-8592-44c4- | bootable_volume | in-use | 10 | Attached to myInstanceFromVolume| | b7d4-0fee2fe1da0c | | | | on /dev/vda | +---------------------+-----------------+--------+------+---------------------------------+
Attach swap or ephemeral disk to an instance
Use the nova boot --swap parameter to
attach a swap disk on boot or the nova boot
--ephemeral parameter to attach an ephemeral disk on boot.
When you terminate the instance, both disks are deleted.
Boot an instance with a 512 MB swap disk and 2 GB ephemeral disk.
$ nova boot --flavor FLAVOR --image IMAGE_ID --swap 512 \
--ephemeral size=2 NAMENote
The flavor defines the maximum swap and ephemeral disk size. You cannot exceed these maximum values.