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.

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 |
+----------------+----------------------------------+