Files
nova/doc/source/user/unified-limits.rst
melanie witt d45379c6b4 docs: Add more information about unified limits
The admin docs are missing some details about enabling unified limits,
like oslo.limit configuration and Keystone roles. This adds more
information about what roles are needed for what actions, how to set
quota limits, quota enforcement, and unified limits in general.

This also removes a couple of tables from the user docs that show
obsolete/deprecated quota limits because they may be more confusing
than helpful considering we don't want new deployments to use them and
they add more clutter to the page.

More info is also added regarding the CLI commands for unified limits
and makes it consistent between the user and admin docs.

Change-Id: Id93f9997d1b217e0c2151c88323564f7a7fefc02
2024-05-17 19:17:05 +00:00

6.8 KiB

Unified Limits Quotas

Since the Nova 28.0.0 (2023.2 Bobcat) release, it is recommended to use Keystone unified limits for Nova quota limits.

For information about legacy quota limits, see the legacy quota documentation </user/quotas>.

Nova uses a quota system for setting limits on resources such as number of instances or amount of CPU that a specific project or user can use.

Quota limits are set by admin and retrieved for enforcement using the Keystone unified limits API.

Types of quota

Unified limit resource names for resources that are tracked as resource classes in the Placement API service follow the naming pattern of the class: prefix followed by the name of the resource class. For example: class:VCPU, class:PCPU, class:MEMORY_MB, class:DISK_GB, class:VGPU.

Quota name Description
class:VCPU Number of shared CPU cores (VCPUs) allowed per project
class:PCPU Number of dedicated CPU cores (PCPUs) allowed per project
servers Number of instances allowed per project
server_key_pairs Number of key pairs allowed per user
server_metadata_items Number of metadata items allowed per instance
class:MEMORY_MB Megabytes of instance ram allowed per project
server_groups Number of server groups per project
server_group_members Number of servers per server group
class:DISK_GB Gigabytes of instance disk allowed per project
class:$RESOURCE_CLASS Any resource class in the Placement API service can have a quota limit specified for it (example: class:VGPU)

OpenStack CLI commands

For full OpenStackClient documentation, see https://docs.openstack.org/python-openstackclient/latest/index.html.

To list default limits for Nova:

openstack registered limit list --service nova

For example:

$ openstack registered limit list --service nova
+----------------------------------+----------------------------------+------------------------------------+---------------+-------------+-----------+
| ID                               | Service ID                       | Resource Name                      | Default Limit | Description | Region ID |
+----------------------------------+----------------------------------+------------------------------------+---------------+-------------+-----------+
| be6dfeebb7c340e8b93b602d41fbff9b | 8b22bf8a66fa4524a522b2a21865bbf2 | servers                            |            10 | None        | None      |
| 8a658096236549788e61f4fcbd5a4a12 | 8b22bf8a66fa4524a522b2a21865bbf2 | class:VCPU                         |            20 | None        | None      |
| 63890db7d6a14401ba55e7f7022b95d0 | 8b22bf8a66fa4524a522b2a21865bbf2 | class:MEMORY_MB                    |         51200 | None        | None      |
| 221ba1c19d2c4272952663828d659013 | 8b22bf8a66fa4524a522b2a21865bbf2 | server_metadata_items              |           128 | None        | None      |
| a32a9080be6b4a5481c16a91fe329e6f | 8b22bf8a66fa4524a522b2a21865bbf2 | server_key_pairs                   |           100 | None        | None      |
| 86408bb7a0e542b18404ec7d348da820 | 8b22bf8a66fa4524a522b2a21865bbf2 | server_groups                      |            10 | None        | None      |
| 17c4552c5aad4afca4813f37530fc897 | 8b22bf8a66fa4524a522b2a21865bbf2 | server_group_members               |            10 | None        | None      |
+----------------------------------+----------------------------------+------------------------------------+---------------+-------------+-----------+

To show details about a default limit:

openstack registered limit show $REGISTERED_LIMIT_ID

For example:

$ openstack registered limit show 8a658096236549788e61f4fcbd5a4a12
+---------------+----------------------------------+
| Field         | Value                            |
+---------------+----------------------------------+
| default_limit | 20                               |
| description   | None                             |
| id            | 8a658096236549788e61f4fcbd5a4a12 |
| region_id     | None                             |
| resource_name | class:VCPU                       |
| service_id    | 8b22bf8a66fa4524a522b2a21865bbf2 |
+---------------+----------------------------------+

To list project limits for Nova:

openstack limit list --service nova

For example:

$ openstack limit list --service nova
+----------------------------------+----------------------------------+----------------------------------+---------------+----------------+-------------+-----------+
| ID                               | Project ID                       | Service ID                       | Resource Name | Resource Limit | Description | Region ID |
+----------------------------------+----------------------------------+----------------------------------+---------------+----------------+-------------+-----------+
| 8b3364b2241e4090aaaa49355c7a5b56 | 5cd3281595a9497ba87209701cd9f3f2 | 8b22bf8a66fa4524a522b2a21865bbf2 | class:VCPU    |              5 | None        | None      |
+----------------------------------+----------------------------------+----------------------------------+---------------+----------------+-------------+-----------+

To list limits for a particular project:

openstack limit list --service nova --project $PROJECT_ID

To show details about a project limit:

openstack limit show $LIMIT_ID

For example:

$ openstack limit show 8b3364b2241e4090aaaa49355c7a5b56
+----------------+----------------------------------+
| Field          | Value                            |
+----------------+----------------------------------+
| description    | None                             |
| domain_id      | None                             |
| id             | 8b3364b2241e4090aaaa49355c7a5b56 |
| project_id     | 5cd3281595a9497ba87209701cd9f3f2 |
| region_id      | None                             |
| resource_limit | 5                                |
| resource_name  | class:VCPU                       |
| service_id     | 8b22bf8a66fa4524a522b2a21865bbf2 |
+----------------+----------------------------------+