From f4132778e6aa426f0b7f50794c7a0cc240c85871 Mon Sep 17 00:00:00 2001 From: Jim Rollenhagen Date: Wed, 3 Aug 2016 09:01:48 -0400 Subject: [PATCH] Add nova scheduler_host_subset_size option to docs This should be set higher than the number of nodes in the deployment, because otherwise nova will continue to pick the same nodes as instances cycle out, meaning some machines may never be used while others get many instances provisioned. This also helps with scheduler races when booting a large number of instances at the same time. Change-Id: I5a898616743105fe5410d7370a91e5c60120b596 --- doc/source/deploy/install-guide.rst | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/doc/source/deploy/install-guide.rst b/doc/source/deploy/install-guide.rst index cf8804b238..9cb34cf792 100644 --- a/doc/source/deploy/install-guide.rst +++ b/doc/source/deploy/install-guide.rst @@ -491,6 +491,14 @@ Compute service's controller nodes and compute nodes.* #scheduler_tracks_instance_changes=True scheduler_tracks_instance_changes=False + # New instances will be scheduled on a host chosen randomly from a subset + # of the N best hosts, where N is the value set by this option. Valid + # values are 1 or greater. Any value less than one will be treated as 1. + # For ironic, this should be set to a number >= the number of ironic nodes + # to more evenly distribute instances across the nodes. + #scheduler_host_subset_size=1 + scheduler_host_subset_size=9999999 + 2. Change these configuration options in the ``ironic`` section. Replace: