Chapter 4. Manage Volumes

A volume is a block storage device that provides persistent storage to OpenStack instances.

4.1. Basic Volume Usage and Configuration

The following procedures describe how to perform basic end-user volume management. These procedures do not require administrative privileges.

4.1.1. Create a Volume

  1. In the dashboard, select Project > Compute > Volumes.

  2. Click Create Volume, and edit the following fields:

    FieldDescription

    Volume name

    Name of the volume.

    Description

    Optional, short description of the volume.

    Type

    Optional volume type (see Section 4.2.3, “Group Volume Settings with Volume Types”).

    If you have multiple Block Storage back ends, you can use this to select a specific back end. See Section 4.1.2, “Specify Back End for Volume Creation” for details.

    Size (GB)

    Volume size (in gigabytes).

    Availability Zone

    Availability zones (logical server groups), along with host aggregates, are a common method for segregating resources within OpenStack. Availability zones are defined during installation. For more information on availability zones and host aggregates, see Section 3.4, “Manage Host Aggregates”.

  3. Specify a Volume Source:

    SourceDescription

    No source, empty volume

    The volume will be empty, and will not contain a file system or partition table.

    Snapshot

    Use an existing snapshot as a volume source. If you select this option, a new Use snapshot as a source list appears; you can then choose a snapshot from the list. For more information about volume snapshots, refer to Section 4.1.8, “Create, Clone, or Delete Volume Snapshots”.

    Image

    Use an existing image as a volume source. If you select this option, a new Use image as a source lists appears; you can then choose an image from the list.

    Volume

    Use an existing volume as a volume source. If you select this option, a new Use volume as a source list appears; you can then choose a volume from the list.

  4. Click Create Volume. After the volume is created, its name appears in the Volumes table.

4.1.2. Specify Back End for Volume Creation

You can configure the Block Storage service to use multiple back ends. For example, Configure OpenStack to Use an NFS Back End provides step-by-step instructions on how to configure the Block Storage service to use an NFS share alongside the default back end.

Whenever multiple Block Storage back ends are configured, you will also need to create a volume type for each back end. You can then use the type to specify which back end should be used for a created volume. For more information about volume types, see Section 4.2.3, “Group Volume Settings with Volume Types”.

To specify a back end when creating a volume, select its corresponding volume type from the Type drop-down list (see Section 4.1.1, “Create a Volume”).

If you do not specify a back end during volume creation, the Block Storage service will automatically choose one for you. By default, the service will choose the back end with the most available free space. You can also configure the Block Storage service to choose randomly among all available back ends instead; for more information, see Section 4.2.6, “Configure How Volumes are Allocated to Multiple Back Ends”.

4.1.3. Edit a Volume’s Name or Description

  1. In the dashboard, select Project > Compute > Volumes.
  2. Select the volume’s Edit Volume button.
  3. Edit the volume name or description as required.
  4. Click Edit Volume to save your changes.
Note

To create an encrypted volume, you must first have a volume type configured specifically for volume encryption. In addition, both Compute and Block Storage services must be configured to use the same static key. For information on how to set up the requirements for volume encryption, refer to Section 4.2.5, “Encrypt Volumes with Static Keys”.

4.1.4. Delete a Volume

  1. In the dashboard, select Project > Compute > Volumes.
  2. In the Volumes table, select the volume to delete.
  3. Click Delete Volumes.
Note

A volume cannot be deleted if it has existing snapshots. For instructions on how to delete snapshots, see Section 4.1.8, “Create, Clone, or Delete Volume Snapshots”.

4.1.5. Attach and Detach a Volume to an Instance

Instances can use a volume for persistent storage. A volume can only be attached to one instance at a time. For more information on instances, see Section 3.1, “Manage Instances”.

4.1.5.1. Attach a Volume to an Instance

  1. In the dashboard, select Project > Compute > Volumes.
  2. Select the volume’s Edit Attachments action. If the volume is not attached to an instance, the Attach To Instance drop-down list is visible.
  3. From the Attach To Instance list, select the instance to which you wish to attach the volume.
  4. Click Attach Volume.

4.1.5.2. Detach a Volume From an Instance

  1. In the dashboard, select Project > Compute > Volumes.
  2. Select the volume’s Manage Attachments action. If the volume is attached to an instance, the instance’s name is displayed in the Attachments table.
  3. Click Detach Volume in this and the next dialog screen.

4.1.6. Set a Volume to Read-Only

You can give multiple users shared access to a single volume without allowing them to edit its contents. To do so, set the volume to read-only using the following command: 

# cinder readonly-mode-update VOLUME true

Replace VOLUME with the ID of the target volume.

To set a read-only volume back to read-write, run: 

# cinder readonly-mode-update VOLUME false

4.1.7. Change a Volume’s Owner

To change a volume’s owner, you will have to perform a volume transfer. A volume transfer is initiated by the volume’s owner, and the volume’s change in ownership is complete after the transfer is accepted by the volume’s new owner.

4.1.7.1. Transfer a Volume from the Command Line

  1. Log in as the volume’s current owner.

  2. List the available volumes: 

    # cinder list

  3. Initiate the volume transfer: 

    # cinder transfer-create VOLUME

    Where VOLUME is the name or ID of the volume you wish to transfer. For example, 

      +------------+--------------------------------------+
  |  Property  |                Value                 |
  +------------+--------------------------------------+
  |  auth_key  |           f03bf51ce7ead189           |
  | created_at |      2014-12-08T03:46:31.884066      |
  |     id     | 3f5dc551-c675-4205-a13a-d30f88527490 |
  |    name    |                 None                 |
  | volume_id  | bcf7d015-4843-464c-880d-7376851ca728 |
  +------------+--------------------------------------+

    The cinder transfer-create command clears the ownership of the volume and creates an id and auth_key for the transfer. These values can be given to, and used by, another user to accept the transfer and become the new owner of the volume.

  4. The new user can now claim ownership of the volume. To do so, the user should first log in from the command line and run: 

    # cinder transfer-accept TRANSFERID TRANSFERKEY

    Where TRANSFERID and TRANSFERKEY are the id and auth_key values returned by the cinder transfer-create command, respectively. For example, 

    # cinder transfer-accept 3f5dc551-c675-4205-a13a-d30f88527490 f03bf51ce7ead189
Note

You can view all available volume transfers using: 

# cinder transfer-list

4.1.7.2. Transfer a Volume Using the Dashboard

Create a volume transfer from the dashboard

  1. As the volume owner in the dashboard, select Projects > Volumes.
  2. In the Actions column of the volume to transfer, select Create Transfer.

  3. In the Create Transfer dialog box, enter a name for the transfer and click Create Volume Transfer.

    The volume transfer is created and in the Volume Transfer screen you can capture the transfer ID and the authorization key to send to the recipient project.

    Note

    The authorization key is available only in the Volume Transfer screen. If you lose the authorization key, you must cancel the transfer and create another transfer to generate a new authorization key.

  4. Close the Volume Transfer screen to return to the volume list.

    The volume status changes to awaiting-transfer until the recipient project accepts the transfer

Accept a volume transfer from the dashboard

  1. As the recipient project owner in the dashboard, select Projects > Volumes.
  2. Click Accept Transfer.

  3. In the Accept Volume Transfer dialog box, enter the transfer ID and the authorization key that you received from the volume owner and click Accept Volume Transfer.

    The volume now appears in the volume list for the active project.

4.1.8. Create, Clone, or Delete Volume Snapshots

You can preserve a volume’s state at a specific point in time by creating a volume snapshot. You can then use the snapshot to clone new volumes.

Warning

Creating a snapshot of a volume that is attached to an instance may corrupt the snapshot. For instructions on how to detach a volume from an instance, see Section 4.1.5.2, “Detach a Volume From an Instance”.

Note

Volume backups are different from snapshots. Backups preserve the data contained in the volume, whereas snapshots preserve the state of a volume at a specific point in time. In addition, you cannot delete a volume if it has existing snapshots. Volume backups are used to prevent data loss, whereas snapshots are used to facilitate cloning.

For this reason, snapshot back ends are typically co-located with volume back ends in order to minimize latency during cloning. By contrast, a backup repository is usually located in a different location (eg. different node, physical storage, or even geographical location) in a typical enterprise deployment. This is to protect the backup repository from any damage that might occur to the volume back end.

For more information about volume backups, refer to Section 4.2.1, “Back Up and Restore a Volume”

To create a volume snapshot:

  1. In the dashboard, select Project > Compute > Volumes.
  2. Select the target volume’s Create Snapshot action.
  3. Provide a Snapshot Name for the snapshot and click Create a Volume Snapshot. The Volume Snapshots tab displays all snapshots.

You can clone new volumes from a snapshot once it appears in the Volume Snapshots table. To do so, select the snapshot’s Create Volume action. For more information about volume creation, see Section 4.1.1, “Create a Volume”.

To delete a snapshot, select its Delete Volume Snapshot action.

If your OpenStack deployment uses a Red Hat Ceph back end, see Section 4.1.8.1, “Protected and Unprotected Snapshots in a Red Hat Ceph Back End” for more information on snapshot security and troubleshooting.

4.1.8.1. Protected and Unprotected Snapshots in a Red Hat Ceph Back End

When using Red Hat Ceph as a back end for your OpenStack deployment, you can set a snapshot to protected in the back end. Attempting to delete protected snapshots through OpenStack (as in, through the dashboard or the cinder snapshot-delete command) will fail.

When this occurs, set the snapshot to unprotected in the Red Hat Ceph back end first. Afterwards, you should be able to delete the snapshot through OpenStack as normal.

For related instructions, see Protecting a Snapshot and Unprotecting a Snapshot.

4.1.9. Upload a Volume to the Image Service

You can upload an existing volume as an image to the Image service directly. To do so:

  1. In the dashboard, select Project > Compute > Volumes.
  2. Select the target volume’s Upload to Image action.
  3. Provide an Image Name for the volume and select a Disk Format from the list.
  4. Click Upload. The QEMU disk image utility uploads a new image of the chosen format using the name you provided.

To view the uploaded image, select Project > Compute > Images. The new image appears in the Images table. For information on how to use and configure images, see Section 1.2, “Manage Images”.

4.2. Advanced Volume Configuration

The following procedures describe how to perform advanced volume management. These procedures require administrative privileges.

4.2.1. Back Up and Restore a Volume

A volume backup is a persistent copy of a volume’s contents. Volume backups are typically created as object stores, and are managed through the Object Storage service by default. You can, however, set up a different repository for your backups; OpenStack supports Ceph, GlusterFS, and NFS as alternative back ends for backups.

When creating a volume backup, all of the backup’s metadata is stored in the Block Storage service’s database. The cinder utility uses this metadata when restoring a volume from the backup. As such, when recovering from a catastrophic database loss, you must restore the Block Storage service’s database first before restoring any volumes from backups. This also presumes that the Block Storage service database is being restored with all the original volume backup metadata intact.

If you wish to configure only a subset of volume backups to survive a catastrophic database loss, you can also export the backup’s metadata. In doing so, you can then re-import the metadata to the Block Storage database later on, and restore the volume backup as normal.

Note

Volume backups are different from snapshots. Backups preserve the data contained in the volume, whereas snapshots preserve the state of a volume at a specific point in time. In addition, you cannot delete a volume if it has existing snapshots. Volume backups are used to prevent data loss, whereas snapshots are used to facilitate cloning.

For this reason, snapshot back ends are typically co-located with volume back ends in order to minimize latency during cloning. By contrast, a backup repository is usually located in a different location (eg. different node, physical storage, or even geographical location) in a typical enterprise deployment. This is to protect the backup repository from any damage that might occur to the volume back end.

For more information about volume snapshots, refer to Section 4.1.8, “Create, Clone, or Delete Volume Snapshots”.

4.2.1.1. Create a Full Volume Backup

To back up a volume, use the cinder backup-create command. By default, this command will create a full backup of the volume. If the volume has existing backups, you can choose to create an incremental backup instead (see Section 4.2.1.2, “Create an Incremental Volume Backup” for details.)

You can create backups of volumes you have access to. This means that users with administrative privileges can back up any volume, regardless of owner. For more information, see Section 4.2.1.1.1, “Create a Volume Backup as an Admin”.

  1. View the ID or Display Name of the volume you wish to back up: 

    # cinder list

  2. Back up the volume: 

    # cinder backup-create VOLUME

    Replace VOLUME with the ID or Display Name of the volume you want to back up. For example: 

      +-----------+--------------------------------------+
  |  Property |                Value                 |
  +-----------+--------------------------------------+
  |     id    | e9d15fc7-eeae-4ca4-aa72-d52536dc551d |
  |    name   |                 None                 |
  | volume_id | 5f75430a-abff-4cc7-b74e-f808234fa6c5 |
  +-----------+--------------------------------------+
    Note

    The volume_id of the resulting backup is identical to the ID of the source volume.

  3. Verify that the volume backup creation is complete: 

    # cinder backup-list

    The volume backup creation is complete when the Status of the backup entry is available.

At this point, you can also export and store the volume backup’s metadata. This allows you to restore the volume backup, even if the Block Storage database suffers a catastrophic loss. To do so, run: 

# cinder --os-volume-api-version 2 backup-export BACKUPID

Where BACKUPID is the ID or name of the volume backup. For example, 

+----------------+------------------------------------------+
|    Property    |                Value                     |
+----------------+------------------------------------------+
| backup_service |     cinder.backup.drivers.swift          |
|   backup_url   | eyJzdGF0dXMiOiAiYXZhaWxhYmxlIiwgIm9iam...|
|                | ...4NS02ZmY4MzBhZWYwNWUiLCAic2l6ZSI6IDF9 |
+----------------+------------------------------------------+

The volume backup metadata consists of the backup_service and backup_url values.

4.2.1.1.1. Create a Volume Backup as an Admin

Users with administrative privileges (such as the default admin account) can back up any volume managed by OpenStack. When an admin backs up a volume owned by a non-admin user, the backup is hidden from the volume owner by default.

As an admin, you can still back up a volume and make the backup available to a specific tenant. To do so, run: 

# cinder --os-auth-url KEYSTONEURL --os-tenant-name TENANTNAME --os-username USERNAME --os-password PASSWD backup-create VOLUME

Where:

  • TENANTNAME is the name of the tenant where you want to make the backup available.
  • USERNAME and PASSWD are the username/password credentials of a user within TENANTNAME.
  • VOLUME is the name or ID of the volume you want to back up.
  • KEYSTONEURL is the URL endpoint of the Identity service (typically http://IP:5000/v2, where IP is the IP address of the Identity service host).

When performing this operation, the resulting backup’s size will count against the quota of TENANTNAME rather than the admin’s tenant.

4.2.1.2. Create an Incremental Volume Backup

By default, the cinder backup-create command will create a full backup of a volume. However, if the volume has existing backups, you can choose to create an incremental backup.

An incremental backup captures any changes to the volume since the last backup (full or incremental). Performing numerous, regular, full back ups of a volume can become resource-intensive as the volume’s size increases over time. In this regard, incremental backups allow you to capture periodic changes to volumes while minimizing resource usage.

To create an incremental volume backup, use the --incremental option. As in: 

# cinder backup-create VOLUME --incremental

Replace VOLUME with the ID or Display Name of the volume you want to back up.

Note

You cannot delete a full backup if it already has an incremental backup. In addition, if a full backup has multiple incremental backups, you can only delete the latest one.

Incremental backups are fully supported on NFS and Object Storage backup repositories. Ceph backup repositories also support incremental backups, but only for volumes that are also stored on a Ceph back end.

4.2.1.3. Restore a Volume After a Block Storage Database Loss

Typically, a Block Storage database loss prevents you from restoring a volume backup. This is because the Block Storage database contains metadata required by the volume backup service (openstack-cinder-backup). This metadata consists of backup_service and backup_url values, which you can export after creating the volume backup (as shown in Section 4.2.1.1, “Create a Full Volume Backup”).

If you exported and stored this metadata, then you can import it to a new Block Storage database (thereby allowing you to restore the volume backup).

  1. As a user with administrative privileges, run: 

    # cinder --os-volume-api-version 2 backup-import backup_service backup_url

    Where backup_service and backup_url are from the metadata you exported. For example, using the exported metadata from Section 4.2.1.1, “Create a Full Volume Backup”: 

    # cinder --os-volume-api-version 2 backup-import cinder.backup.drivers.swift eyJzdGF0dXMi...c2l6ZSI6IDF9
+----------+--------------------------------------+
| Property |                Value                 |
+----------+--------------------------------------+
|    id    | 77951e2f-4aff-4365-8c64-f833802eaa43 |
|   name   |                 None                 |
+----------+--------------------------------------+
  2. After the metadata is imported into the Block Storage service database, you can restore the volume as normal (see Section 4.2.1.4, “Restore a Volume from a Backup”).

4.2.1.4. Restore a Volume from a Backup

  1. Find the ID of the volume backup you wish to use: 

    # cinder backup-list

    The Volume ID should match the ID of the volume you wish to restore.

  2. Restore the volume backup: 

    # cinder backup-restore BACKUP_ID

    Where BACKUP_ID is the ID of the volume backup you wish to use.

  3. If you no longer need the backup, delete it: 

    # cinder backup-delete BACKUP_ID

4.2.1.5. View and Modify a Tenant’s Backup Quota

Unlike most tenant storage quotas (number of volumes, volume storage, snapshots, etc.), backup quotas cannot be modified through the dashboard yet.

Backup quotas can only be modified through the command-line interface; namely, through the cinder quota-update command.

To view the storage quotas of a specific tenant (TENANTNAME), run: 

# cinder quota-show TENANTNAME

To update the maximum number of backups (MAXNUM) that can be created in a specific tenant, run: 

# cinder quota-update --backups MAXNUM TENANTNAME

To update the maximum total size of all backups (MAXGB) within a specific tenant, run: 

# cinder quota-update --backup-gigabytes MAXGB TENANTNAME

To view the storage quota usage of a specific tenant, run: 

# cinder quota-usage TENANTNAME

4.2.1.6. Enable Volume Backup Management Through the Dashboard

You can now create, view, delete, and restore volume backups through the dashboard. To perform any of these functions, go to the Project > Compute > Volumes > Volume Backups tab.

However, the Volume Backups tab is not enabled by default. To enable it, configure the dashboard accordingly:

  1. Open /etc/openstack-dashboard/local_settings.

  2. Search for the following setting: 

    OPENSTACK_CINDER_FEATURES = {
    'enable_backup': False,
}

    Change this setting to: 

    OPENSTACK_CINDER_FEATURES = {
    'enable_backup': True,
}

  3. Restart the dashboard by restarting the httpd service: 

    # systemctl restart httpd.service

4.2.1.7. Set an NFS Share as a Backup Repository

By default, the Block Storage service uses the Object Storage service as a repository for backups. You can configure the Block Storage service to use an existing NFS share as a backup repository instead. To do so:

  1. Log in to the node hosting the backup service (openstack-cinder-backup) as a user with administrative privileges.

  2. Configure the Block Storage service to use the NFS backup driver (cinder.backup.drivers.nfs): 

    # openstack-config --set /etc/cinder/cinder.conf DEFAULT backup_driver cinder.backup.drivers.nfs

  3. Set the details of the NFS share that you want to use as a backup repository: 

    # openstack-config --set /etc/cinder/cinder.conf DEFAULT backup_share NFSHOST:PATH

    Where:

    • NFSHOST is the IP address or hostname of the NFS server.
    • PATH is the absolute path of the NFS share on NFSHOST.

  4. If you want to set any optional mount settings for the NFS share, run: 

    # openstack-config --set /etc/cinder/cinder.conf DEFAULT backup_mount_options NFSMOUNTOPTS

    Where NFSMOUNTOPTS is a comma-separated list of NFS mount options (for example, rw,sync). For more information on supported mount options, see the man pages for nfs and mount.

  5. Restart the Block Storage backup service to apply your changes: 

    # systemctl restart openstack-cinder-backup.service
4.2.1.7.1. Set a Different Backup File Size

The backup service limits backup files sizes to a maximum backup file size. If you are backing up a volume that exceeds this size, the resulting backup will be split into multiple chunks. The default backup file size is 1.8GB.

To set a different backup file size, run: 

# openstack-config --set /etc/cinder/cinder.conf DEFAULT backup_file_size SIZE

Replace SIZE with the file size you want, in bytes. Restart the Block Storage backup service to apply your changes: 

# systemctl restart openstack-cinder-backup.service

4.2.2. Migrate a Volume

Only an administrator can migrate volumes; volumes to be migrated cannot be in use nor can they have any snapshots.

  1. As an administrative user, list all available volumes: 

    # cinder list

  2. List the available back ends (hosts) and their respective availability zones: 

    # cinder-manage host list

  3. Initiate the migration: 

    # cinder migrate VOLUME BACKEND

    Where:

    • VOLUME is the ID of the volume to be migrated.
    • BACKEND is the back end to where the volume should be migrated.

  4. View the current status of the volume to be migrated: 

    # cinder show VOLUME

    For example, 

    # cinder show 45a85c3c-3715-484d-ab5d-745da0e0bd5a
+---------------------------------------+------------------+
|                Property               |      Value       |
+---------------------------------------+------------------+
|                  ...                  |       ...        |
|         os-vol-host-attr:host         |      server1     |
|     os-vol-mig-status-attr:migstat    |       None       |
|                  ...                  |       ...        |
+---------------------------------------+------------------+

During migration, note the following attributes:

os-vol-host-attr:host
The volume’s current back end. Once the migration completes, this displays the target back end (namely, BACKEND).
os-vol-mig-status-attr:migstat
The status of the migration. A status of None means a migration is no longer in progress.

4.2.3. Group Volume Settings with Volume Types

OpenStack allows you to create volume types, which allows you apply the type’s associated settings when creating a volume (Section 4.1.1, “Create a Volume”). For example, you can associate:

Settings are associated with volume types using key-value pairs called Extra Specs. When you specify a volume type during volume creation, the Block Storage scheduler applies these key/value pairs as settings. You can associate multiple key/value pairs to the same volume type.

Volume types provide the capability to provide different users with storage tiers. By associating specific performance, resilience, and other settings as key/value pairs to a volume type, you can map tier-specific settings to different volume types. You can then apply tier settings when creating a volume by specifying the corresponding volume type.

Note

Available and supported Extra Specs vary per volume driver. Consult your volume driver’s documentation for a list of valid Extra Specs.

4.2.3.1. Create and Configure a Volume Type

  1. As an admin user in the dashboard, select Admin > Volumes > Volume Types.
  2. Click Create Volume Type.
  3. Enter the volume type name in the Name field.
  4. Click Create Volume Type. The new type appears in the Volume Types table.
  5. Select the volume type’s View Extra Specs action.
  6. Click Create, and specify the Key and Value. The key/value pair must be valid; otherwise, specifying the volume type during volume creation will result in an error.
  7. Click Create. The associated setting (key/value pair) now appears in the Extra Specs table.

By default, all volume types are accessible to all OpenStack tenants. If you need to create volume types with restricted access, you will need to do so through the CLI. For instructions, see Section 4.2.3.4, “Create and Configure Private Volume Types”.

Note

You can also associate a QOS Spec to the volume type. For details, refer to Section 4.2.4.2, “Associate a QOS Spec with a Volume Type”.

4.2.3.2. Edit a Volume Type

  1. As an admin user in the dashboard, select Admin > Volumes > Volume Types.
  2. In the Volume Types table, select the volume type’s View Extra Specs action.

  3. On the Extra Specs table of this page, you can:

    • Add a new setting to the volume type. To do this, click Create, and specify the key/value pair of the new setting you want to associate to the volume type.
    • Edit an existing setting associated with the volume type. To do this, select the setting’s Edit action.
    • Delete existing settings associated with the volume type. To do this, select the extra specs' check box and click Delete Extra Specs in this and the next dialog screen.

4.2.3.3. Delete a Volume Type

To delete a volume type, select its corresponding check boxes from the Volume Types table and click Delete Volume Types.

4.2.3.4. Create and Configure Private Volume Types

By default, all volume types are visible to all tenants. You can override this during volume type creation and set it to private. To do so, you will need to set the type’s Is_Public flag to False.

Private volume types are useful for restricting access to certain volume settings. Typically, these are settings that should only be usable by specific tenants; examples include new back ends or ultra-high performance configurations that are being tested.

To create a private volume type, run: 

# cinder --os-volume-api-version 2 type-create --is-public false _VTYPE_

+ Replace VTYPE with the name of the private volume type.

By default, private volume types are only accessible to their creators. However, admin users can find and view private volume types using the following command: 

# cinder --os-volume-api-version 2 type-list --all

This command will list both public and private volume types, and will also include the name and ID of each one. You will need the volume type’s ID to provide access to it.

Access to a private volume type is granted at the tenant level. To grant a tenant access to a private volume type, run: 

# cinder --os-volume-api-version 2 type-access-add --volume-type _VTYPEID_ --project-id _TENANTID_

Where:

  • VTYPEID is the ID of the private volume type.
  • TENANTID is the ID of the project/tenant you are granting access to VTYPEID.

To view which tenants have access to a private volume type, run: 

# cinder --os-volume-api-version 2 type-access-list --volume-type _VTYPE_

To remove a tenant from the access list of a private volume type, run: 

# cinder --os-volume-api-version 2 type-access-remove --volume-type _VTYPE_ --project-id _TENANTID_
Note

By default, only users with administrative privileges can create, view, or configure access for private volume types.

4.2.4. Use Quality-of-Service Specifications

You can map multiple performance settings to a single Quality-of-Service specification (QOS Specs). Doing so allows you to provide performance tiers for different user types.

Performance settings are mapped as key/value pairs to QOS Specs, similar to the way volume settings are associated to a volume type. However, QOS Specs are different from volume types in the following respects:

  • QOS Specs are used to apply performance settings, which include limiting read/write operations to disks. Available and supported performance settings vary per storage driver.

    To determine which QOS Specs are supported by your back end, consult the documentation of your back end device’s volume driver.

  • Volume types are directly applied to volumes, whereas QOS Specs are not. Rather, QOS Specs are associated to volume types. During volume creation, specifying a volume type also applies the performance settings mapped to the volume type’s associated QOS Specs.

4.2.4.1. Create and Configure a QOS Spec

As an administrator, you can create and configure a QOS Spec through the QOS Specs table. You can associate more than one key/value pair to the same QOS Spec.

  1. As an admin user in the dashboard, select Admin > Volumes > Volume Types.
  2. On the QOS Specs table, click Create QOS Spec.
  3. Enter a name for the QOS Spec.

  4. In the Consumer field, specify where the QOS policy should be enforced:

    Table 4.1. Consumer Types

    TypeDescription

    back-end

    QOS policy will be applied to the Block Storage back end.

    front-end

    QOS policy will be applied to Compute.

    both

    QOS policy will be applied to both Block Storage and Compute.

  5. Click Create. The new QOS Spec should now appear in the QOS Specs table.
  6. In the QOS Specs table, select the new spec’s Manage Specs action.
  7. Click Create, and specify the Key and Value. The key/value pair must be valid; otherwise, specifying a volume type associated with this QOS Spec during volume creation will fail.
  8. Click Create. The associated setting (key/value pair) now appears in the Key-Value Pairs table.

4.2.4.2. Associate a QOS Spec with a Volume Type

As an administrator, you can associate a QOS Spec to an existing volume type using the Volume Types table.

  1. As an administrator in the dashboard, select Admin > Volumes > Volume Types.
  2. In the Volume Types table, select the type’s Manage QOS Spec Association action.
  3. Select a QOS Spec from the QOS Spec to be associated list.
  4. Click Associate. The selected QOS Spec now appears in the Associated QOS Spec column of the edited volume type.

4.2.4.3. Disassociate a QOS Spec from a Volume Type

  1. As an administrator in the dashboard, select Admin > Volumes > Volume Types.
  2. In the Volume Types table, select the type’s Manage QOS Spec Association action.
  3. Select None from the QOS Spec to be associated list.
  4. Click Associate. The selected QOS Spec is no longer in the Associated QOS Spec column of the edited volume type.

4.2.5. Encrypt Volumes with Static Keys

Volume encryption helps provide basic data protection in case the volume back-end is either compromised or outright stolen. The contents of an encrypted volume can only be read with the use of a specific key; both Compute and Block Storage services must be configured to use the same key in order for instances to use encrypted volumes. This section describes how to configure an OpenStack deployment to use a single key for encrypting volumes.

Important

At present, volume encryption is only supported on volumes backed by block devices. Encryption of network-attached volumes (such as RBD) or file-based volumes (such as NFS) is still unsupported.

4.2.5.1. Configure a Static Key

The first step in implementing basic volume encryption is to set a static key. This key must be a hex string, which will be used by the Block Storage volume service (namely, openstack-cinder-volume) and all Compute services (openstack-nova-compute). To configure both services to use this key, set the key as the fixed_key value in the [keymgr] section of both service’s respective configuration files.

  1. From the command line, log in as root to the node hosting openstack-cinder-volume.

  2. Set the static key: 

    # openstack-config --set /etc/cinder/cinder.conf keymgr fixed_key HEX_KEY

    Replace HEX_KEY with a 16-digit alphanumeric hex key (for example, 0000000000000000000000000000000000000000000000000000000000000000).

  3. Restart the Block Storage volume service: 

    # openstack-service restart cinder-volume

  4. Log in to the node hosting openstack-nova-compute, and set the same static key: 

    # openstack-config --set /etc/nova/nova.conf keymgr fixed_key HEX_KEY
    Note

    If you have multiple Compute nodes (multiple nodes hosting openstack-nova-compute), then you need to set the same static key in /etc/nova/nova.conf of each node.

  5. Restart the Compute service: 

    # openstack-service restart nova-compute
    Note

    Likewise, if you set the static key on multiple Compute nodes, you need to restart the openstack-nova-compute service on each node as well.

At this point, both Compute and Block Storage volume services can now use the same static key to encrypt/decrypt volumes. That is, new instances will be able to use volumes encrypted with the static key (HEX_KEY).

4.2.5.2. Configure Volume Type Encryption

To create volumes encrypted with the static key from Section 4.2.5.1, “Configure a Static Key”, you need an encrypted volume type. Configuring a volume type as encrypted involves setting what provider class, cipher, and key size it should use. To do so, run: 

# cinder encryption-type-create --cipher aes-xts-plain64 --key_size BITSIZE --control_location front-end VOLTYPE nova.volume.encryptors.luks.LuksEncryptor

Where:

  • BITSIZE is the key size (for example, 512 for a 512-bit key).
  • VOLTYPE is the name of the volume type you want to encrypt.

This command sets the nova.volume.encryptors.luks.LuksEncryptor provider class and aes-xts-plain64 cipher. As of this release, this is the only supported class/cipher configuration for volume encryption.

Once you have an encrypted volume type, you can invoke it to automatically create encrypted volumes. Specifically, select the encrypted volume type from the Type drop-down list in the Create Volume window (see to Section 4.1, “Basic Volume Usage and Configuration”).

4.2.6. Configure How Volumes are Allocated to Multiple Back Ends

If the Block Storage service is configured to use multiple back ends, you can use configured volume types to specify where a volume should be created. For details, see Section 4.1.2, “Specify Back End for Volume Creation”.

The Block Storage service will automatically choose a back end if you do not specify one during volume creation. Block Storage sets the first defined back end as a default; this back end will be used until it runs out of space. At that point, Block Storage will set the second defined back end as a default, and so on.

If this is not suitable for your needs, you can use the filter scheduler to control how Block Storage should select back ends. This scheduler can use different filters to triage suitable back ends, such as:

AvailabilityZoneFilter
Filters out all back ends that do not meet the availability zone requirements of the requested volume
CapacityFilter
Selects only back ends with enough space to accommodate the volume
CapabilitiesFilter
Selects only back ends that can support any specified settings in the volume

To configure the filter scheduler:

  1. Enable the FilterScheduler. 

    # openstack-config --set /etc/cinder/cinder.conf DEFAULT scheduler_driver cinder.scheduler.filter_scheduler.FilterScheduler

  2. Set which filters should be active: 

    # openstack-config --set /etc/cinder/cinder.conf DEFAULT scheduler_default_filters AvailabilityZoneFilter,CapacityFilter,CapabilitiesFilter

  3. Configure how the scheduler should select a suitable back end. If you want the scheduler:

    • To always choose the back end with the most available free space, run: 

      # openstack-config --set /etc/cinder/cinder.conf DEFAULT scheduler_default_weighers AllocatedCapacityWeigher
# openstack-config --set /etc/cinder/cinder.conf DEFAULT allocated_capacity_weight_multiplier -1.0

    • To choose randomly among all suitable back ends, run: 

      # openstack-config --set /etc/cinder/cinder.conf DEFAULT scheduler_default_weighers ChanceWeigher

  4. Restart the Block Storage scheduler to apply your settings: 

    # openstack-service restart openstack-cinder-scheduler