Document unset/reset wrinkle for *_allocation_ratio options

This is a follow up to I43a23a3290db0c835fed01b8d6a38962dc61adce
which makes the cpu/disk/ram_allocation_ratio config "sticky" in
that once set to a non-default value, it is not possible to reset
back to the default behavior (when config is 0.0) on an existing
compute node record by unsetting the option from nova.conf. To
reset back to the defaults, the non-0.0 default would have to be
explicitly put into config, so cpu_allocation_ratio=16.0 for example.

Alternatively operators could delete the nova-compute service
record via the DELETE /os-services/{service_id} REST API and
restart the nova-compute service to get a new compute_nodes record,
but that workaround is messy and left undocumented in config.

Change-Id: I908615d82ead0f70f8e6d2d78d5dcaed8431084d
Related-Bug: #1789654
(cherry picked from commit c45adaca5d)
(cherry picked from commit a039f83977)
This commit is contained in:
Matt Riedemann 2018-09-04 12:11:57 -04:00 committed by Tony Breeds
parent 3a8e98cbfc
commit f8c0c4671c
1 changed files with 9 additions and 3 deletions

View File

@ -425,7 +425,9 @@ configuration value if no per-aggregate setting is found.
NOTE: This can be set per-compute, or if set to 0.0, the value
set on the scheduler node(s) or compute node(s) will be used
and defaulted to 16.0.
and defaulted to 16.0. Once set to a non-default value, it is not possible
to "unset" the config to get back to the default behavior. If you want
to reset back to the default, explicitly specify 16.0.
NOTE: As of the 16.0.0 Pike release, this configuration option is ignored
for the ironic.IronicDriver compute driver and is hardcoded to 1.0.
@ -452,7 +454,9 @@ configuration value if no per-aggregate setting found.
NOTE: This can be set per-compute, or if set to 0.0, the value
set on the scheduler node(s) or compute node(s) will be used and
defaulted to 1.5.
defaulted to 1.5. Once set to a non-default value, it is not possible
to "unset" the config to get back to the default behavior. If you want
to reset back to the default, explicitly specify 1.5.
NOTE: As of the 16.0.0 Pike release, this configuration option is ignored
for the ironic.IronicDriver compute driver and is hardcoded to 1.0.
@ -483,7 +487,9 @@ instances.
NOTE: This can be set per-compute, or if set to 0.0, the value
set on the scheduler node(s) or compute node(s) will be used and
defaulted to 1.0.
defaulted to 1.0. Once set to a non-default value, it is not possible
to "unset" the config to get back to the default behavior. If you want
to reset back to the default, explicitly specify 1.0.
NOTE: As of the 16.0.0 Pike release, this configuration option is ignored
for the ironic.IronicDriver compute driver and is hardcoded to 1.0.