openstack/nova
Code Issues Proposed changes

api-ref: add warnings about forcing the host for live migrate/evacuate

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Bypassing the scheduler during a live migration or evacuation
is not something we want people to be doing as it can easily fail
if the specified host is already full or doesn't provide something
required by the instance, plus it's a nightmare for tracking allocations
in the Placement service when we're bypassing the scheduler.

Because of this, we should have some warnings in the API reference
about doing this, which this patch adds.

Change-Id: I85e7c2677f4d5eccc1e7f349de06960b53ef148d
This commit is contained in:
Matt Riedemann 2017-08-31 15:50:29 -04:00
parent 2a4ca8bd6a
commit a4609a834b
1 changed files with 26 additions and 2 deletions
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28
api-ref/source/parameters.yaml
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@ -2680,6 +2680,11 @@ force_evacuate:
description: | description: |
Force an evacuation by not verifying the provided destination host by the Force an evacuation by not verifying the provided destination host by the
scheduler. scheduler.
.. warning:: This could result in failures to actually evacuate the
instance to the specified host. It is recommended to either not specify
a host so that the scheduler will pick one, or specify a host without
``force=True`` set.
in: body in: body
required: false required: false
type: boolean type: boolean
@ -2688,6 +2693,11 @@ force_live_migrate:
description: | description: |
Force a live-migration by not verifying the provided destination host by Force a live-migration by not verifying the provided destination host by
the scheduler. the scheduler.
.. warning:: This could result in failures to actually live migrate the
instance to the specified host. It is recommended to either not specify
a host so that the scheduler will pick one, or specify a host without
``force=True`` set.
in: body in: body
required: false required: false
type: boolean type: boolean
@ -2777,6 +2787,13 @@ host:
description: | description: |
The name or ID of the host to which the server is evacuated. The name or ID of the host to which the server is evacuated.
If you omit this parameter, the scheduler chooses a host. If you omit this parameter, the scheduler chooses a host.
.. warning:: Prior to microversion 2.29, specifying a host will bypass
validation by the scheduler, which could result in failures to actually
evacuate the instance to the specified host, or over-subscription of the
host. It is recommended to either not specify a host so that the
scheduler will pick one, or specify a host with microversion >= 2.29 and
without ``force=True`` set.
in: body in: body
required: false required: false
type: string type: string
@ -2825,8 +2842,15 @@ host_memory_mb:
type: integer type: integer
host_migration: host_migration:
description: | description: |
The host to which to migrate the server. If this parameter is ``None``, the scheduler The host to which to migrate the server. If this parameter is ``None``,
chooses a host. the scheduler chooses a host.
.. warning:: Prior to microversion 2.30, specifying a host will bypass
validation by the scheduler, which could result in failures to actually
migrate the instance to the specified host, or over-subscription of the
host. It is recommended to either not specify a host so that the
scheduler will pick one, or specify a host with microversion >= 2.30 and
without ``force=True`` set.
in: body in: body
required: true required: true
type: string type: string