17 KiB
Consistency groups
Consistency groups enable you to create snapshots from multiple file system shares at the same point in time. For example, a database might place its tables, logs, and configuration on separate shares. To restore this database from a previous point in time, it makes sense to restore the logs, tables, and configuration together from the exact same point in time.
The Shared File System service allows you to create a snapshot of the consistency group and restore all shares that were associated with a consistency group.
Note
The consistency groups and snapshots are an
experimental Shared File Systems API in the Liberty
release. Contributors can change or remove the experimental part of the
Shared File Systems API in further releases without maintaining backward
compatibility. The experimental API have an
X-OpenStack-Manila-API-Experimental: true header in their
HTTP requests.
Consistency groups
Note
Before using consistency groups, make sure the Shared File System
driver that you are running has consistency group support. You can check
it in the manila-scheduler service reports. The
consistency_group_support can have such values:
poolorhost. Consistency groups are supported. Specifies the level of consistency groups support.false. Consistency groups are not supported.
The manila cg-create command creates a new consistency
group. With this command, you can specify a share network, and one or
more share types. In the example a consistency group
cgroup1 was created by specifying two comma-separated share
types:
$ manila cg-create --name cgroup1 --description "My first CG." --share-types my_type1,default --share-network my_share_net
+----------------------+--------------------------------------+
| Property | Value |
+----------------------+--------------------------------------+
| status | creating |
| description | My first CG. |
| source_cgsnapshot_id | None |
| created_at | 2015-09-29T15:01:12.102472 |
| share_network_id | 5c3cbabb-f4da-465f-bc7f-fadbe047b85a |
| share_server_id | None |
| host | None |
| project_id | 20787a7ba11946adad976463b57d8a2f |
| share_types | a4218aa5-f16a-42b3-945d-113496d40558 |
| | c0086582-30a6-4060-b096-a42ec9d66b86 |
| id | 6fdd91bc-7a48-48b4-8e40-0f4f98d0ecd6 |
| name | cgroup1 |
+----------------------+--------------------------------------+Check that consistency group is in available status:
$ manila cg-show cgroup1
+----------------------+--------------------------------------+
| Property | Value |
+----------------------+--------------------------------------+
| status | available |
| description | My first CG. |
| source_cgsnapshot_id | None |
| created_at | 2015-09-29T15:05:40.000000 |
| share_network_id | 5c3cbabb-f4da-465f-bc7f-fadbe047b85a |
| share_server_id | None |
| host | manila@generic1#GENERIC1 |
| project_id | 20787a7ba11946adad976463b57d8a2f |
| share_types | c0086582-30a6-4060-b096-a42ec9d66b86 |
| | a4218aa5-f16a-42b3-945d-113496d40558 |
| id | 6fdd91bc-7a48-48b4-8e40-0f4f98d0ecd6 |
| name | cgroup1 |
+----------------------+--------------------------------------+To add a share to the consistency group create a share with a --consistency-group option
where you specify the ID of the consistency group in
available status:
$ manila create nfs 1 --name "Share2" --description "My second share" --share-type default --share-network my_share_net --consistency-group cgroup1
+-----------------------------+--------------------------------------+
| Property | Value |
+-----------------------------+--------------------------------------+
| status | None |
| share_type_name | default |
| description | My second share |
| availability_zone | None |
| share_network_id | None |
| export_locations | [] |
| share_server_id | None |
| host | None |
| snapshot_id | None |
| is_public | False |
| task_state | None |
| snapshot_support | True |
| id | 7bcd888b-681b-4836-ac9c-c3add4e62537 |
| size | 1 |
| name | Share2 |
| share_type | c0086582-30a6-4060-b096-a42ec9d66b86 |
| created_at | 2015-09-29T15:09:24.156387 |
| export_location | None |
| share_proto | NFS |
| consistency_group_id | 6fdd91bc-7a48-48b4-8e40-0f4f98d0ecd6 |
| source_cgsnapshot_member_id | None |
| project_id | 20787a7ba11946adad976463b57d8a2f |
| metadata | {} |
+-----------------------------+--------------------------------------+Administrators can rename the consistency group, or change its
description using manila cg-update command. Delete the group with
manila cg-delete
command.
As an administrator, you can also reset the state of a consistency
group and force-delete a specified consistency group in any state. Use
the policy.json file to grant permissions for these actions
to other roles.
Use manila cg-reset-state [--state <state>] <consistency_group>
to update the state of a consistency group explicitly. A valid value of
a status are available, error,
creating, deleting,
error_deleting. If no state is provided,
available will be used.
$ manila cg-reset-state cgroup1 --state errorUse manila cg-delete <consistency_group> [<consistency_group> ...]
to soft-delete one or more consistency groups.
Note
A consistency group can be deleted only if it has no dependent shared_file_systems_cgsnapshots.
$ manila cg-delete cgroup1Use manila cg-delete --force <consistency_group>
[<consistency_group> ...] to force-delete a specified
consistency group in any state.
$ manila cg-delete --force cgroup1Consistency group snapshots
You can create snapshots of consistency groups. To create a snapshot, specify the ID or name of the consistency group. After creating a consistency group snapshot, it is possible to generate a consistency group from it.
Create a snapshot of consistency group cgroup1:
$ manila cg-snapshot-create cgroup1 --name CG_snapshot1 --description "A snapshot of the first CG."
+----------------------+--------------------------------------+
| Property | Value |
+----------------------+--------------------------------------+
| status | creating |
| name | CG_snapshot1 |
| created_at | 2015-09-29T15:26:16.839704 |
| consistency_group_id | 6fdd91bc-7a48-48b4-8e40-0f4f98d0ecd6 |
| project_id | 20787a7ba11946adad976463b57d8a2f |
| id | 876ad24c-1efd-4607-a2b1-6a2c90034fa5 |
| description | A snapshot of the first CG. |
+----------------------+--------------------------------------+Check the status of created consistency group snapshot:
$ manila cg-snapshot-show CG_snapshot1
+----------------------+--------------------------------------+
| Property | Value |
+----------------------+--------------------------------------+
| status | available |
| name | CG_snapshot1 |
| created_at | 2015-09-29T15:26:22.000000 |
| consistency_group_id | 6fdd91bc-7a48-48b4-8e40-0f4f98d0ecd6 |
| project_id | 20787a7ba11946adad976463b57d8a2f |
| id | 876ad24c-1efd-4607-a2b1-6a2c90034fa5 |
| description | A snapshot of the first CG. |
+----------------------+--------------------------------------+Administrators can rename the consistency group snapshot, or change
its description using the cg-snapshot-update command, or delete it with the
cg-snapshot-delete
command.
A consistency group snapshot can have members. To add a
member, include the --consistency-group optional parameter in the
create share command. This ID must match the ID of the consistency group
from which the consistency group snapshot was created. Then, while
restoring data, for example, and operating with consistency group
snapshots you can quickly find which shares belong to a specified
consistency group.
You created the share Share2 in cgroup1
consistency group. Since you made a snapshot of it, you can see that the
only member of the consistency group snapshot is Share2
share:
$ manila cg-snapshot-members CG_snapshot1
+--------------+------+----------------------------+----------------+--------------+--------------+
| Id | Size | Created_at | Share_protocol | Share_id | Share_type_id|
+--------------+------+----------------------------+----------------+--------------+--------------+
| 5c62af2b-... | 1 | 2015-09-29T15:26:22.000000 | NFS | 7bcd888b-... | c0086582-... |
+--------------+------+----------------------------+----------------+--------------+--------------+After you create a consistency group snapshot, you can create a consistency group from it:
$ manila cg-create --source-cgsnapshot-id 876ad24c-1efd-4607-a2b1-6a2c90034fa5 --name cgroup2 --description "A consistency group from a CG snapshot."
+----------------------+-----------------------------------------+
| Property | Value |
+----------------------+-----------------------------------------+
| status | creating |
| description | A consistency group from a CG snapshot. |
| source_cgsnapshot_id | 876ad24c-1efd-4607-a2b1-6a2c90034fa5 |
| created_at | 2015-09-29T15:47:47.937991 |
| share_network_id | None |
| share_server_id | None |
| host | manila@generic1#GENERIC1 |
| project_id | 20787a7ba11946adad976463b57d8a2f |
| share_types | c0086582-30a6-4060-b096-a42ec9d66b86 |
| | a4218aa5-f16a-42b3-945d-113496d40558 |
| id | ffee08d9-c86c-45e5-861e-175c731daca2 |
| name | cgroup2 |
+----------------------+-----------------------------------------+Check the consistency group list. Two groups now appear:
$ manila cg-list
+-------------------+---------+-----------------------------------------+-----------+
| id | name | description | status |
+-------------------+---------+-----------------------------------------+-----------+
| 6fdd91bc-7a48-... | cgroup1 | My first CG. | available |
| ffee08d9-c86c-... | cgroup2 | A consistency group from a CG snapshot. | available |
+-------------------+---------+-----------------------------------------+-----------+Check a list of the shares. New share with
ba52454e-2ea3-47fa-a683-3176a01295e6 ID appeared after the
consistency group cgroup2 was built from a snapshot with a
member.
$ manila list
+------+-------+-----+------------+----------+----------+-----------+--------------------------+
| ID | Name | Size| Share Proto| Status | Is Public| Share Type| Host |
+------+-------+-----+------------+----------+----------+-----------+--------------------------+
| 7bc..| Share2| 1 | NFS | available| False | c008658...| manila@generic1#GENERIC1 |
| ba5..| None | 1 | NFS | available| False | c008658...| manila@generic1#GENERIC1 |
+------+-------+-----+------------+----------+----------+-----------+--------------------------+Print detailed information about new share:
Note
Pay attention on the source_cgsnapshot_member_id and
consistency_group_id fields in a new share. It has
source_cgsnapshot_member_id that is equal to the ID of the
consistency group snapshot and consistency_group_id that is
equal to the ID of cgroup2 created from a snapshot.
$ manila show ba52454e-2ea3-47fa-a683-3176a01295e6
+-----------------------------+---------------------------------------------------------------+
| Property | Value |
+-----------------------------+---------------------------------------------------------------+
| status | available |
| share_type_name | default |
| description | None |
| availability_zone | None |
| share_network_id | None |
| export_locations | 10.254.0.5:/shares/share-5acadf4d-f81a-4515-b5ce-3ab641ab4d1e |
| share_server_id | None |
| host | manila@generic1#GENERIC1 |
| snapshot_id | None |
| is_public | False |
| task_state | None |
| snapshot_support | True |
| id | ba52454e-2ea3-47fa-a683-3176a01295e6 |
| size | 1 |
| name | None |
| share_type | c0086582-30a6-4060-b096-a42ec9d66b86 |
| created_at | 2015-09-29T15:47:48.000000 |
| share_proto | NFS |
| consistency_group_id | ffee08d9-c86c-45e5-861e-175c731daca2 |
| source_cgsnapshot_member_id | 5c62af2b-0870-4d00-b3fa-174831eb15ca |
| project_id | 20787a7ba11946adad976463b57d8a2f |
| metadata | {} |
+-----------------------------+---------------------------------------------------------------+As an administrator, you can also reset the state of a consistency
group snapshot with cg-snapshot-reset-state and force-delete a
specified consistency group snapshot in any state using cg-snapshot-delete with
--force key. Use the
policy.json file to grant permissions for these actions to
other roles.