nova/releasenotes/notes/deprecate-core-ram-disk-filters-06a3ce2a820426d9.yaml
Matt Riedemann 243ba85130 Deprecate Core/Ram/DiskFilter
The time has come.

These filters haven't been necessary since Ocata [1]
when the filter scheduler started using placement
to filter on VCPU, DISK_GB and MEMORY_MB. The
only reason to use them with any in-tree scheduler
drivers is if using the CachingScheduler which doesn't
use placement, but the CachingScheduler itself has
been deprecated since Pike [2]. Furthermore, as of
change [3] in Stein, the ironic driver no longer
reports vcpu/ram/disk inventory for ironic nodes
which will make these filters filter out ironic nodes
thinking they don't have any inventory. Also, as
noted in [4], the DiskFilter does not account for
volume-backed instances and may incorrectly filter
out a host based on disk inventory when it would
otherwise be OK if the instance is not using local
disk.

The related aggregate filters are left intact for
now, see blueprint placement-aggregate-allocation-ratios.

[1] Ie12acb76ec5affba536c3c45fbb6de35d64aea1b
[2] Ia7ff98ff28b7265058845e46b277317a2bfc96d2
[3] If2b8c1a76d7dbabbac7bb359c9e572cfed510800
[4] I9c2111f7377df65c1fc3c72323f85483b3295989

Change-Id: Id62136d293da55e4bb639635ea5421a33b6c3ea2
Related-Bug: #1787910
2018-08-24 19:32:27 -04:00

11 lines
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YAML

---
deprecations:
- |
The ``CoreFilter``, ``DiskFilter`` and ``RamFilter`` are now deprecated.
VCPU, DISK_GB and MEMORY_MB filtering is performed natively using the
Placement service when using the ``filter_scheduler`` driver. Users of the
``caching_scheduler`` driver may still rely on these filters but the
``caching_scheduler`` driver is itself deprecated. Furthermore, enabling
these filters may incorrectly filter out baremetal nodes which must be
`scheduled using custom resource classes <https://docs.openstack.org/ironic/latest/install/configure-nova-flavors.html>`_.