From 6ef48140999e6fe2d23e6e0c61dfdd41e07359e9 Mon Sep 17 00:00:00 2001 From: Matt Riedemann Date: Thu, 3 Sep 2015 18:45:08 -0700 Subject: [PATCH] Clarify max_local_block_devices config option usage The previous wording for the max_local_block_devices config option made it sound like if you set it to 0 that you could restrict to only booting instances from volumes, which is not the case - but is apparently something that some operators want (this came up in the related bug and in IRC). This updates the help text with a description that ndipanov put in the bug report which makes the 0 case more clear. Co-Authored-By: Nikola Dipanov Related-Bug: #1436314 Change-Id: I01a9e2f193b50285966690efd771da432a7ad40c --- nova/compute/api.py | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/nova/compute/api.py b/nova/compute/api.py index 32e8065eb4cf..7664dcac9be1 100644 --- a/nova/compute/api.py +++ b/nova/compute/api.py @@ -114,8 +114,15 @@ compute_opts = [ default=3, help='Maximum number of devices that will result ' 'in a local image being created on the hypervisor node. ' - 'Setting this to 0 means nova will allow only ' - 'boot from volume. A negative number means unlimited.'), + 'A negative number means unlimited. Setting ' + 'max_local_block_devices to 0 means that any request that ' + 'attempts to create a local disk will fail. This option ' + 'is meant to limit the number of local discs (so root ' + 'local disc that is the result of --image being used, and ' + 'any other ephemeral and swap disks). 0 does not mean ' + 'that images will be automatically converted to volumes ' + 'and boot instances from volumes - it just means that all ' + 'requests that attempt to create a local disk will fail.'), ] ephemeral_storage_encryption_group = cfg.OptGroup(