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Diffstat (limited to 'doc/source/admin/scheduling.rst')
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diff --git a/doc/source/admin/scheduling.rst b/doc/source/admin/scheduling.rst index 9071c92ac9..353514ab55 100644 --- a/doc/source/admin/scheduling.rst +++ b/doc/source/admin/scheduling.rst @@ -1049,6 +1049,37 @@ Otherwise, it will fall back to the more than one value is found for a host in aggregate metadata, the minimum value will be used. +``HypervisorVersionWeigher`` +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. versionadded:: 28.0.0 (Bobcat) + +Weigh hosts by their relative hypervisor version reported by the virt driver. + +While the hypervisor_version filed for all virt drivers is an int, +each nova virt driver uses a different algorithm to convert the hypervisor-specific +version sequence into an int. As such the values are not directly comparable between +hosts with different hypervisors. + +For example, the ironic virt driver uses the ironic API micro-version as the hypervisor +version for a given node. The libvirt driver uses the libvirt version +i.e. Libvirt `7.1.123` becomes `700100123` vs Ironic `1.82` becomes `1` +Hyper-V `6.3` becomes `6003`. + +If you have a mixed virt driver deployment in the ironic vs non-ironic +case nothing special needs to be done. ironic nodes are scheduled using custom +resource classes so ironic flavors will never match non-ironic compute nodes. + +If a deployment has multiple non-ironic virt drivers it is recommended to use aggregates +to group hosts by virt driver. While this is not strictly required, it is +desirable to avoid bias towards one virt driver. +see :ref:`filtering_hosts_by_isolating_aggregates` and :ref:`AggregateImagePropertiesIsolation` +for more information. + +The default behavior of the HypervisorVersionWeigher is to select newer hosts. +If you prefer to invert the behavior set the +:oslo.config:option:`filter_scheduler.hypervisor_version_weight_multiplier` option +to a negative number and the weighing has the opposite effect of the default. Utilization-aware scheduling ---------------------------- |