Doc follow up for PCI in placement

This fixes the doc comments for the already merged (or being merged)
patches in the series.

blueprint: pci-device-tracking-in-placement
Change-Id: Ia99138d603722a66c9a6ac61b035384d86ccca75
This commit is contained in:
Balazs Gibizer 2022-08-30 13:07:03 +02:00
parent 11bcf2676c
commit efb6fd834e
2 changed files with 19 additions and 4 deletions

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@ -51,6 +51,20 @@ capabilities.
Nova will ignore PCI devices reported by the hypervisor if the address is
outside of these ranges.
.. versionchanged:: 26.0.0 (Zed):
PCI passthrough device inventories now can be tracked in Placement.
For more information, refer to :ref:`pci-tracking-in-placement`.
.. versionchanged:: 26.0.0 (Zed):
The nova-compute service will refuse to start if both the parent PF and its
children VFs are configured in :oslo.config:option:`pci.device_spec`.
For more information, refer to :ref:`pci-tracking-in-placement`.
.. versionchanged:: 26.0.0 (Zed):
The nova-compute service will refuse to start with
:oslo.config:option:`pci.device_spec` configuration that uses the
``devname`` field.
Enabling PCI passthrough
------------------------
@ -348,6 +362,7 @@ You can also configure this for PCI passthrough devices by specifying the
policy in the alias configuration via :oslo.config:option:`pci.alias`. For more
information, refer to :oslo.config:option:`the documentation <pci.alias>`.
.. _pci-tracking-in-placement:
PCI tracking in Placement
-------------------------
@ -402,13 +417,13 @@ be added to the resource provider representing the matching PCI devices.
(Zed) the nova-compute service will refuse to start with such configuration.
It is suggested to use the PCI address of the device instead.
The nova-compute service makes sure that already existing instances with PCI
The nova-compute service makes sure that existing instances with PCI
allocations in the nova DB will have a corresponding PCI allocation in
placement. This allocation healing also acts on any new instances regardless of
the status of the scheduling part of this feature to make sure that the nova
DB and placement are in sync. There is one limitation of the healing logic.
It assumes that there is no in-progress migration when the nova-compute service
is upgraded. If there is an in-progress migration, then the PCI allocation on
is upgraded. If there is an in-progress migration then the PCI allocation on
the source host of the migration will not be healed. The placement view will be
consistent after such migration is completed or reverted.
@ -417,7 +432,7 @@ Reconfiguring the PCI devices on the hypervisor or changing the
nova-compute service is supported in the following cases:
* new devices are added
* devices without allocation is removed
* devices without allocation are removed
Removing a device that has allocations is not supported. If a device having any
allocation is removed then the nova-compute service will keep the device and

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@ -2,7 +2,7 @@
features:
- |
Nova started tracking PCI devices in Placement. This is an optional feature
disable by default while we are implementing inventory tracking and
disabled by default while we are implementing inventory tracking and
scheduling support for both PCI passthrough devices and SR-IOV devices
consumed via Neutron ports. Please read our
`documentation <https://docs.openstack.org/nova/latest/admin/pci-passthrough.html#pci-tracking-in-placement>`_