18 March 2024

Major upgrade to the Compute (Nova) service. Most of the changes are internal however there are some public-facing changes as described below.

Compute API Version Change

The most significant change is retirement of the v2 compute API which was deprecated in August 2022. This is replaced by the v2.1 API which features backwards compatibility with v2 but also introduces ‘microversions’ to determine the available features and capabilities of the compute service.

The first aspect of the API change is that the URL path changes from /v2 to /v2.1. So for example the compute v2 API for the Porirua region has now changed to https://api.nz-por-1.catalystcloud.io:8774/v2.1. The updated API URLs can be found on the API page of the dashboard.

Most client applications should obtain the correct URL automatically from the service catalogue and therefore not require additional configuration. If any customers have specifically configured any applications or scripts to use the v2 API then they should be updated to use the v2.1 API instead.

The v2.1 API is required for some of the new compute features and will enable additional features in future. It also retains full backwards-compatibility with the old v2 API, so older software that only supports API v2 can be configured to use the v2.1 API without loss of functionality.

Note that the v2.1 API supports a number of new features that are dependent on the specific microversion of the API. The highest supported API microversion after this upgrade is 2.42. Requests for features that are newer than this microversion may result in an error being returned instead of the desired action being performed.

These errors may occur with existing scripts, configurations and tools (e.g. Terraform/OpenTofu), particularly software that uses gophercloud to communicate with the compute API. Requests for newer features may have been silently ignored when interfacing with the v2 API in the past but may start to return errors after the upgrade.

If customers encounter errors with the compute service after the upgrade, check instance deployment scripts to see if such features are being requested and remove these options.

An example of a feature included in Terraform (and derivative products) is specifying the volume type at instance creation. This is not supported in the 2.42 compute API so will return an error. To avoid this, please ensure that openstack_compute_volume_attach_v2 resources do not use the volume_type argument.

More information on the features available up to v2.42 can be found in the OpenStack compute API documentation.


Instance tags

Simple string tags can now be added to servers to assist with filtering and sorting. There is also now support for virtual device role tagging.

Device tags

Device role tagging can assist with identifying which device is which inside the guest instance. When booting an instance, an optional arbitrary tag parameter can be set on virtual network interfaces and/or block device mappings. This tag is exposed to the instance through the metadata API. Each tagged virtual network interface is listed along with information about the virtual hardware, such as bus type (e.g. PCI), bus address (e.g. 0000:00:02.0) and MAC address. For tagged block devices, the exposed hardware metadata includes the bus (e.g. SCSI), bus address (e.g. 1:0:2:0) and serial number.

The metadata service contains a corresponding devices section which lists any devices that are tagged as described in the previous paragraph, along with their hardware metadata.

API Microversion Header consistency

Microversions may now (since microversion 2.27) be requested with the OpenStack-API-Version: compute 2.27 header, in alignment with OpenStack-wide standards. The original format, X-OpenStack-Nova-API-Version: 2.27, may still be used.

Deprecation Notices

Compute API v2

The compute v2 API endpoint is being replaced by the v2.1 API endpoint. Refer to details earlier in this page for more information.

EC2 API Deprecation

The EC2-compatible compute API provides an S3-like compute API service. There has not been any usage activity logged on this API for some time so it is now deprecated and will be retired after 31 March 2024.

This does not affect the S3 object storage API or the ability to manage EC2 credentials; these features will continue to function as normal.