openstack/nova
Code Issues Proposed changes

Docs and functional test for max_local_block_devices

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We get questions about if it's possible to configure nova to
always use cinder for root volumes even if the user isn't
explicitly booting from volume. This change adds a FAQ entry
about that to the block device mappings docs and also suggests
a way to force users to use volume-backed servers using the
max_local_block_devices option. The config option help for that
option is also cleaned up since --image is a CLI option but we
should stick to REST API parameters in descriptions and the
default mentioned in the help already gets rendered by oslo.config.
Finally, a simple functional test is added to assert the workaround
mentioned in the docs.

Change-Id: I3e77796b051e8d007fefe2eea06d38e8265e8272
This commit is contained in:
Matt Riedemann
2019-08-23 12:12:08 -04:00
parent af3433a255
commit 364fa30062
3 changed files with 41 additions and 7 deletions
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13
nova/conf/compute.py
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@@ -82,21 +82,20 @@ Possible values:
Maximum number of devices that will result in a local image being
created on the hypervisor node.
A negative number means unlimited. Setting max_local_block_devices
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.
(so root local disc that is the result of ``imageRef`` being used when
creating a server, 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.
Possible values:
* 0: Creating a local disk is not allowed.
* Negative number: Allows unlimited number of local discs.
* Positive number: Allows only these many number of local discs.
(Default value is 3).
"""),
cfg.ListOpt('compute_monitors',
default=[],