nova/doc/source/admin/configuration/cross-cell-resize.rst

Cross-cell resize

Train spec: https://specs.openstack.org/openstack/nova-specs/specs/train/approved/cross-cell-resize.html

Flesh this out to describe what cross-cell resize is, how it is triggered (policy), related configuration (long_rpc_timeout) including the CrossCellWeigher, limitations and known issues, recovering from failures during a cross-cell resize, maybe a flow chart for the overall process in the code, minimum upgrade requirements and supported drivers (libvirt-only at this time).

Limitations

These are known to not yet be supported in the code:

• Instances with ports attached that have bandwidth-aware resource provider allocations.
• Reschedules

These are likely not to work since they have not been validated by testing:

• Instances with PCI devices attached.
• Instances with a NUMA topology.