Files
nova/doc/source/user/launch-instance-from-volume.rst
melanie witt bb0906f4f3 Add configuration of maximum disk devices to attach
This adds a new config option to control the maximum number of disk
devices allowed to attach to a single instance, which can be set per
compute host.

The configured maximum is enforced when device names are generated
during server create, rebuild, evacuate, unshelve, live migrate, and
attach volume. When the maximum is exceeded during server create,
rebuild, evacuate, unshelve, or live migrate, the server will go into
ERROR state and the server fault will contain the reason. When the
maximum is exceeded during an attach volume request, the request fails
fast in the API with a 403 error.

The configured maximum on the destination is not enforced before cold
migrate because the maximum is enforced in-place only (the destination
is not checked over RPC). The configured maximum is also not enforced
on shelved offloaded servers because they have no compute host, and the
option is implemented at the nova-compute level.

Part of blueprint conf-max-attach-volumes

Change-Id: Ia9cc1c250483c31f44cdbba4f6342ac8d7fbe92b
2019-01-30 15:47:10 +00:00

19 KiB

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 openstack server create command:

p{0.25textwidth}

Task openstack server create 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.

  1. 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     |
    +---------------------+--------------------------------------+
  2. List volumes.

    $ openstack volume list
    +--------------------------------------+--------------+-----------+------+-------------+
    | ID                                   | Name         | Status    | Size | Attached to |
    +--------------------------------------+--------------+-----------+------+-------------+
    | b8f7bbec-6274-4cd7-90e7-60916a5e75d4 | my-volume    | available |    8 |             |
    +--------------------------------------+--------------+-----------+------+-------------+
  3. Boot an instance from an image and attach the empty volume to the instance.

    $ openstack server create --flavor 2 --image 98901246-af91-43d8-b5e6-a4506aa8f369 \
      --block-device source=volume,id=d620d971-b160-4c4e-8652-2513d74e2080,dest=volume,shutdown=preserve \
      myInstanceWithVolume
    +--------------------------------------+--------------------------------------------+
    | Field                                | 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.

  1. 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                                               |
    +------------------+------------------------------------------------------+
  2. 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.

  3. To create a bootable volume from an image and launch an instance from this volume, use the --block-device parameter.

    For example:

    $ openstack server create --flavor FLAVOR --block-device \
      source=SOURCE,id=ID,dest=DEST,size=SIZE,shutdown=PRESERVE,bootindex=INDEX \
      NAME

    The parameters are:

    • --flavor The flavor ID or name.
    • --block-device source=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, and blank.

      id=ID

      The ID of the source object.

      dest=DEST

      The type of the target virtual device. Valid values are volume and local.

      size=SIZE

      The size of the volume that is created.

      shutdown={preserve|remove}

      What to do with the volume when the instance is deleted. preserve does not delete the volume. remove deletes the volume.

      bootindex=INDEX

      Orders the boot disks. Use 0 to boot from this volume.

    • NAME. The name for the server.

    See block-device-mapping for more details on these parameters.

  4. Create a bootable volume from an image. Cinder makes a volume bootable when --image parameter is passed.

    $ openstack volume create --image IMAGE_ID --size SIZE_IN_GB bootable_volume

    Note

    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.

  5. Create a VM from previously created bootable volume. The volume is not deleted when the instance is terminated.

    $ openstack server create --flavor 2 --volume VOLUME_ID \
      --block-device source=volume,id=$VOLUME_ID,dest=volume,size=10,shutdown=preserve,bootindex=0 \
      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                             | {}                             |
    +--------------------------------------+--------------------------------+
  6. List volumes to see the bootable volume and its attached myInstanceFromVolume instance.

    $ 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.