From 99838a89987a6c4250f4eb0a55ed7d199853b5fe Mon Sep 17 00:00:00 2001 From: Mark Goddard Date: Tue, 26 Mar 2024 12:42:46 +0000 Subject: [PATCH] docs: Add an upgrade doc note about Glance show_multiple_locations Operators may decide to replace this option. --- doc/source/operations/upgrading.rst | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/doc/source/operations/upgrading.rst b/doc/source/operations/upgrading.rst index 53df5aef2..d44f1e917 100644 --- a/doc/source/operations/upgrading.rst +++ b/doc/source/operations/upgrading.rst @@ -94,6 +94,20 @@ custom configuration that uses the Keystone admin port. One such example is the config for Ceph RGW in ``etc/kayobe/cephadm.yml``. Be sure to update any manual references to the old port. +Glance show_multiple_locations disabled +--------------------------------------- + +Kolla Ansible no longer sets ``show_multiple_locations = True`` in Glance by +default when Glance's Ceph RBD backend is enabled. This was applied as a fix +but operators must note that this, in turn, disables Cinder and Nova's +optimisations. In particular, this can increase instance creation times due to +a lack of copy-on-write. + +On the other hand, these optimisations might have been causing other trouble +for operators. Please see `LP#1992153 +`__. Operators relying +on this feature can set the flag themselves using service config overrides. + Known issues ============