openstack/ironic
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[docs] mention new nova scheduler option

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also add some notes for mixed hypervisor case.

Change-Id: I77d13e8180f7cae0a1eb370329cebc6bb2768fe0
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Pavlo Shchelokovskyy 2018-01-16 18:31:33 +02:00
parent 0970e3d031
commit b327f70b8e
1 changed files with 20 additions and 0 deletions
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doc/source/install/configure-compute.rst
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@ -90,6 +90,9 @@ service's controller nodes and compute nodes.
# subset of the 999 hosts. The big value is used to avoid race # subset of the 999 hosts. The big value is used to avoid race
# conditions, when several instances are scheduled on the same bare # conditions, when several instances are scheduled on the same bare
# metal nodes. This is not a problem when resource classes are used. # metal nodes. This is not a problem when resource classes are used.
# You should carefully consider increasing this option from its
# default value of 1 in mixed hypervisor case, as placement
# of virtual instances will become less optimal.
host_subset_size=999 host_subset_size=999
# This flag enables a different set of scheduler filters, which is more # This flag enables a different set of scheduler filters, which is more
@ -97,8 +100,25 @@ service's controller nodes and compute nodes.
# with their exact counterparts, to make sure only nodes strictly # with their exact counterparts, to make sure only nodes strictly
# matching the flavor are picked. These filters do not work with # matching the flavor are picked. These filters do not work with
# scheduling based on resource classes only. # scheduling based on resource classes only.
# You must not enable this option if you have compute hosts
# with other than 'ironic' drivers as enabling it will make scheduling
# of virtual instances problematic.
use_baremetal_filters=True use_baremetal_filters=True
#. Consider enabling the following option on controller nodes:
.. code-block:: ini
[filter_scheduler]
# Enabling this option is beneficial as it reduces re-scheduling events
# for ironic nodes when scheduling is based on resource classes,
# especially for mixed hypervisor case with host_subset_size = 1.
# However enabling it will also make packing of VMs on hypervisors
# less dense even when scheduling weights are completely disabled.
#shuffle_best_same_weighed_hosts = false
#. Carefully consider the following option: #. Carefully consider the following option:
.. code-block:: ini .. code-block:: ini