From b327f70b8ef9f7adaf99d7db0625feaf78d5734a Mon Sep 17 00:00:00 2001 From: Pavlo Shchelokovskyy Date: Tue, 16 Jan 2018 18:31:33 +0200 Subject: [PATCH] [docs] mention new nova scheduler option also add some notes for mixed hypervisor case. Change-Id: I77d13e8180f7cae0a1eb370329cebc6bb2768fe0 --- doc/source/install/configure-compute.rst | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/doc/source/install/configure-compute.rst b/doc/source/install/configure-compute.rst index aa0471edfc..573a7c5db1 100644 --- a/doc/source/install/configure-compute.rst +++ b/doc/source/install/configure-compute.rst @@ -90,6 +90,9 @@ service's controller nodes and compute nodes. # subset of the 999 hosts. The big value is used to avoid race # conditions, when several instances are scheduled on the same bare # 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 # 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 # matching the flavor are picked. These filters do not work with # 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 +#. 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: .. code-block:: ini