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Diffstat (limited to 'doc/source/admin/pci-passthrough.rst')
| -rw-r--r-- | doc/source/admin/pci-passthrough.rst | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/doc/source/admin/pci-passthrough.rst b/doc/source/admin/pci-passthrough.rst index de79792f16..09a963603d 100644 --- a/doc/source/admin/pci-passthrough.rst +++ b/doc/source/admin/pci-passthrough.rst @@ -65,6 +65,10 @@ capabilities. :oslo.config:option:`pci.device_spec` configuration that uses the ``devname`` field. +.. versionchanged:: 27.0.0 (2023.1 Antelope): + Nova provides Placement based scheduling support for servers with flavor + based PCI requests. This support is disable by default. + Enabling PCI passthrough ------------------------ @@ -442,6 +446,39 @@ removed and VFs from the same PF is configured (or vice versa) then nova-compute will refuse to start as it would create a situation where both the PF and its VFs are made available for consumption. +Since nova 27.0.0 (2023.1 Antelope) scheduling and allocation of PCI devices +in Placement can also be enabled via +:oslo.config:option:`filter_scheduler.pci_in_placement`. Please note that this +should only be enabled after all the computes in the system is configured to +report PCI inventory in Placement via +enabling :oslo.config:option:`pci.report_in_placement`. In Antelope flavor +based PCI requests are support but Neutron port base PCI requests are not +handled in Placement. + +If you are upgrading from an earlier version with already existing servers with +PCI usage then you must enable :oslo.config:option:`pci.report_in_placement` +first on all your computes having PCI allocations and then restart the +nova-compute service, before you enable +:oslo.config:option:`filter_scheduler.pci_in_placement`. The compute service +will heal the missing PCI allocation in placement during startup and will +continue healing missing allocations for future servers until the scheduling +support is enabled. + +If a flavor requests multiple ``type-VF`` devices via +:nova:extra-spec:`pci_passthrough:alias` then it is important to consider the +value of :nova:extra-spec:`group_policy` as well. The value ``none`` +allows nova to select VFs from the same parent PF to fulfill the request. The +value ``isolate`` restricts nova to select each VF from a different parent PF +to fulfill the request. If :nova:extra-spec:`group_policy` is not provided in +such flavor then it will defaulted to ``none``. + +Symmetrically with the ``resource_class`` and ``traits`` fields of +:oslo.config:option:`pci.device_spec` the :oslo.config:option:`pci.alias` +configuration option supports requesting devices by Placement resource class +name via the ``resource_class`` field and also support requesting traits to +be present on the selected devices via the ``traits`` field in the alias. If +the ``resource_class`` field is not specified in the alias then it is defaulted +by nova to ``CUSTOM_PCI_<vendor_id>_<product_id>``. For deeper technical details please read the `nova specification. <https://specs.openstack.org/openstack/nova-specs/specs/zed/approved/pci-device-tracking-in-placement.html>`_ |