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:
Task |
nova boot parameter |
Information |
|---|---|---|
Boot an instance from an image and attach a non-bootable volume. |
|
|
Create a volume from an image and boot an instance from that volume. |
|
|
Boot from an existing source image, volume, or snapshot. |
|
|
Attach a swap disk to an instance. |
|
|
Attach an ephemeral disk to an instance. |
|
Note
To attach a volume to a running instance, refer to the Cinder documentation.
Note
The maximum limit on the number of disk devices allowed to attach to
a single server is configurable with the option
compute.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 \ NAME
The 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 Mapping in Nova for 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 horizonadmin/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 NAME
Note
The flavor defines the maximum swap and ephemeral disk size. You cannot exceed these maximum values.
