![Stephen Finucane](/assets/img/avatar_default.png)
These are in the cinder doc tree so of course they're block storage-related. Change-Id: Ic1950ff89021a89de397619eef17f8100eb3d847 Signed-off-by: Stephen Finucane <stephenfin@redhat.com>
10 KiB
Generic volume groups
Generic volume group support is available in OpenStack Block Storage (cinder) since the Newton release. The support is added for creating group types and group specs, creating groups of volumes, and creating snapshots of groups. The group operations can be performed using the Block Storage command line.
A group type is a type for a group just like a volume type for a volume. A group type can also have associated group specs similar to extra specs for a volume type.
In cinder, there is a group construct called consistency group. Consistency groups only support consistent group snapshots and only a small number of drivers can support it. The following is a list of drivers that support consistency groups and the release when the support was added:
- Juno: EMC VNX
- Kilo: EMC VMAX, IBM (GPFS, Storwize, SVC, and XIV), ProphetStor, Pure
- Liberty: Dell Storage Center, EMC XtremIO, HPE 3Par and LeftHand
- Mitaka: EMC ScaleIO, NetApp Data ONTAP, SolidFire
- Newton: CoprHD, FalconStor, Huawei
Consistency group cannot be extended easily to serve other purposes. A tenant may want to put volumes used in the same application together in a group so that it is easier to manage them together, and this group of volumes may or may not support consistent group snapshot. Generic volume group is introduced to solve this problem.
There is a plan to migrate existing consistency group operations to use generic volume group operations in future releases. More information can be found in Cinder specs.
Note
Only Block Storage V3 API supports groups. You can specify
--os-volume-api-version 3.x
when using the cinder command line for group operations where
3.x contains a microversion value for
that command. The generic volume group feature was completed in several
patches. As a result, the minimum required microversion is different for
group types, groups, and group snapshots APIs.
The following group type operations are supported:
- Create a group type.
- Delete a group type.
- Set group spec for a group type.
- Unset group spec for a group type.
- List group types.
- Show a group type details.
- Update a group.
- List group types and group specs.
The following group and group snapshot operations are supported:
Create a group, given group type and volume types.
Note
A group must have one group type. A group can support more than one volume type. The scheduler is responsible for finding a back end that can support the given group type and volume types.
A group can only contain volumes hosted by the same back end.
A group is empty upon its creation. Volumes need to be created and added to it later.
Show a group.
List groups.
Delete a group.
Modify a group.
Create a volume and add it to a group.
Create a snapshot for a group.
Show a group snapshot.
List group snapshots.
Delete a group snapshot.
Create a group from a group snapshot.
Create a group from a source group.
The following operations are not allowed if a volume is in a group:
Volume migration.
Volume retype.
Volume deletion.
Note
A group has to be deleted as a whole with all the volumes.
The following operations are not allowed if a volume snapshot is in a group snapshot:
Volume snapshot deletion.
Note
A group snapshot has to be deleted as a whole with all the volume snapshots.
The details of group type operations are shown in the following. The minimum microversion to support group type and group specs is 3.11:
Create a group type:
cinder --os-volume-api-version 3.11 group-type-create
[--description DESCRIPTION]
[--is-public IS_PUBLIC]
NAME
Note
The parameter NAME
is required. The
--is-public IS_PUBLIC
determines whether the group type is
accessible to the public. It is True
by default. By
default, the policy on privileges for creating a group type is
admin-only.
Show a group type:
cinder --os-volume-api-version 3.11 group-type-show
GROUP_TYPE
Note
The parameter GROUP_TYPE
is the name or UUID of a group
type.
List group types:
cinder --os-volume-api-version 3.11 group-type-list
Note
Only admin can see private group types.
Update a group type:
cinder --os-volume-api-version 3.11 group-type-update
[--name NAME]
[--description DESCRIPTION]
[--is-public IS_PUBLIC]
GROUP_TYPE_ID
Note
The parameter GROUP_TYPE_ID
is the UUID of a group type.
By default, the policy on privileges for updating a group type is
admin-only.
Delete group type or types:
cinder --os-volume-api-version 3.11 group-type-delete
GROUP_TYPE [GROUP_TYPE ...]
Note
The parameter GROUP_TYPE
is name or UUID of the group
type or group types to be deleted. By default, the policy on privileges
for deleting a group type is admin-only.
Set or unset group spec for a group type:
cinder --os-volume-api-version 3.11 group-type-key
GROUP_TYPE ACTION KEY=VALUE [KEY=VALUE ...]
Note
The parameter GROUP_TYPE
is the name or UUID of a group
type. Valid values for the parameter ACTION
are
set
or unset
. KEY=VALUE
is the
group specs key and value pair to set or unset. For unset, specify only
the key. By default, the policy on privileges for setting or unsetting
group specs key is admin-only.
List group types and group specs:
cinder --os-volume-api-version 3.11 group-specs-list
Note
By default, the policy on privileges for seeing group specs is admin-only.
The details of group operations are shown in the following. The minimum microversion to support groups operations is 3.13.
Create a group:
cinder --os-volume-api-version 3.13 group-create
[--name NAME]
[--description DESCRIPTION]
[--availability-zone AVAILABILITY_ZONE]
GROUP_TYPE VOLUME_TYPES
Note
The parameters GROUP_TYPE
and VOLUME_TYPES
are required. GROUP_TYPE
is the name or UUID of a group
type. VOLUME_TYPES
can be a list of names or UUIDs of
volume types separated by commas without spaces in between. For example,
volumetype1,volumetype2,volumetype3.
.
Show a group:
cinder --os-volume-api-version 3.13 group-show
GROUP
Note
The parameter GROUP
is the name or UUID of a group.
List groups:
cinder --os-volume-api-version 3.13 group-list
[--all-tenants [<0|1>]]
Note
--all-tenants
specifies whether to list groups for all
tenants. Only admin can use this option.
Create a volume and add it to a group:
cinder --os-volume-api-version 3.13 create
--volume-type VOLUME_TYPE
--group-id GROUP_ID SIZE
Note
When creating a volume and adding it to a group, the parameters
VOLUME_TYPE
and GROUP_ID
must be provided.
This is because a group can support more than one volume type.
Delete a group:
cinder --os-volume-api-version 3.13 group-delete
[--delete-volumes]
GROUP [GROUP ...]
Note
--delete-volumes
allows or disallows groups to be
deleted if they are not empty. If the group is empty, it can be deleted
without --delete-volumes
. If the group is not empty, the
flag is required for it to be deleted. When the flag is specified, the
group and all volumes in the group will be deleted.
Modify a group:
cinder --os-volume-api-version 3.13 group-update
[--name NAME]
[--description DESCRIPTION]
[--add-volumes UUID1,UUID2,......]
[--remove-volumes UUID3,UUID4,......]
GROUP
Note
The parameter UUID1,UUID2,......
is the UUID of one or
more volumes to be added to the group, separated by commas. Similarly
the parameter UUID3,UUID4,......
is the UUID of one or more
volumes to be removed from the group, separated by commas.
The details of group snapshots operations are shown in the following. The minimum microversion to support group snapshots operations is 3.14.
Create a snapshot for a group:
cinder --os-volume-api-version 3.14 group-snapshot-create
[--name NAME]
[--description DESCRIPTION]
GROUP
Note
The parameter GROUP
is the name or UUID of a group.
Show a group snapshot:
cinder --os-volume-api-version 3.14 group-snapshot-show
GROUP_SNAPSHOT
Note
The parameter GROUP_SNAPSHOT
is the name or UUID of a
group snapshot.
List group snapshots:
cinder --os-volume-api-version 3.14 group-snapshot-list
[--all-tenants [<0|1>]]
[--status STATUS]
[--group-id GROUP_ID]
Note
--all-tenants
specifies whether to list group snapshots
for all tenants. Only admin can use this option.
--status STATUS
filters results by a status.
--group-id GROUP_ID
filters results by a group id.
Delete group snapshot:
cinder --os-volume-api-version 3.14 group-snapshot-delete
GROUP_SNAPSHOT [GROUP_SNAPSHOT ...]
Note
The parameter GROUP_SNAPSHOT
specifies the name or UUID
of one or more group snapshots to be deleted.
Create a group from a group snapshot or a source group:
$ cinder --os-volume-api-version 3.14 group-create-from-src
[--group-snapshot GROUP_SNAPSHOT]
[--source-group SOURCE_GROUP]
[--name NAME]
[--description DESCRIPTION]
Note
The parameter GROUP_SNAPSHOT
is a name or UUID of a
group snapshot. The parameter SOURCE_GROUP
is a name or
UUID of a source group. Either GROUP_SNAPSHOT
or
SOURCE_GROUP
must be specified, but not both.