Current Series Release Notes

15.0.0-37

Prelude

The 2026.1 release focuses on reducing technical debt and improving operational reliability. The most significant change is the removal of the eventlet dependency, completing Cyborg’s migration to native threading for oslo.service and oslo.messaging. Database session management has been modernized to use the current oslo.db enginefacade API, replacing the legacy facade that was removed upstream. Additionally, the cyborg-agent now validates its Placement resource provider at startup, fixing a long-standing hostname mismatch issue between Cyborg and Nova. Several accelerator driver bugs have also been corrected.

The documentation has also been enhanced, a new driver configuration guide has been added covering all supported accelerator drivers with configuration examples and troubleshooting tips, and a release liaison guide has been added for contributors.

Upgrade Notes

  • The cyborg-agent now requires Placement to be reachable at startup. Previously the agent would start and only fail during the update_usage periodic task. This aligns with nova-compute behavior where the compute service validates its resource provider at startup. Ensure Placement is available before starting cyborg-agent.

    The agent retries the resource provider lookup up to 3 times by default (configurable via [agent] resource_provider_startup_retries), using exponential backoff. The default of 3 retries gives approximately 7 seconds of tolerance (1s + 2s + 4s) for nova-compute to create the resource provider.

  • Cyborg no longer uses eventlet. The eventlet dependency has been removed and Cyborg now uses the native threading backend for oslo.service and the threading RPC server. No configuration changes are required. Packagers should ensure that oslo.service[threading] is installed as a dependency.

  • The cyborg-wsgi-api wsgi_scripts entry point has been removed. This setuptools-specific mechanism for installing a WSGI script was deprecated in the 2025.1 cycle. Deployments using mod_wsgi or uWSGI should reference the WSGI application directly via cyborg.wsgi.api:application as described in the WSGI deployment documentation.

Bug Fixes

  • NVIDIA GPU cards such as the A100 expose SR-IOV Virtual Functions (VFs) when virtualized. The NVIDIA GPU driver was incorrectly reporting these VFs as standalone GPU accelerators. A new [gpu_devices]/filter_sriov_vfs configuration option (default False) allows operators to filter out VF devices so that only Physical Functions and mediated devices are reported. The option defaults to False because enabling it may remove VF-backed resources from Placement without cleaning up existing allocations first. Operators should ensure no instances hold VF allocations before enabling this option.

  • Fixed a crash in the PCI driver where discovery of devices with vendor IDs not present in the vendor map would raise an AttributeError. The PCI driver now gracefully handles unknown vendors by skipping the vendor-specific trait and falling back to using the raw vendor ID as the driver name.

  • A new configuration option [agent] resource_provider_name that allows operators to explicitly specify the name of the compute resource provider in Placement has been added.

    This defaults to socket.getfqdn() which typically matches libvirt’s hypervisor hostname behavior. If the resource provider lookup fails with this name, Cyborg will automatically fall back to using CONF.host, providing backward compatibility for existing deployments.

    The cyborg-agent now validates the resource provider name at startup by querying Placement directly. It tries the configured name (defaulting to socket.getfqdn()) first, then falls back to CONF.host. If neither hostname finds a valid resource provider, the agent will fail to start with a clear error message.

    A new [agent] resource_provider_startup_retries option (default: 3) controls how many times the agent retries the Placement lookup at startup, using exponential backoff (1s, 2s, 4s, …). This tolerates a startup race where nova-compute has not yet created the resource provider in Placement.

    This fixes Bug 2139369 and addresses the disconnect between how Cyborg identifies the compute resource provider name and how Nova/Placement names it.

    Previously, Cyborg used CONF.host (which defaults to socket.gethostname()) to look up the compute resource provider in Placement. However, Nova uses libvirt’s hostname determination, which typically returns the FQDN. This mismatch caused PlacementResourceProviderNotFound errors on systems where the short hostname differs from the FQDN.