42 lines
1.8 KiB
ReStructuredText
42 lines
1.8 KiB
ReStructuredText
..
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Licensed under the Apache License, Version 2.0 (the "License"); you may
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not use this file except in compliance with the License. You may obtain
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a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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License for the specific language governing permissions and limitations
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under the License.
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====================================
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Heat Stack Lifecycle Scheduler Hints
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====================================
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This is a mechanism whereby when heat processes a stack with Server or Volume
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resources, the stack id, root stack id, stack resource uuid, stack resource
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name and the path in the stack can be passed by heat to nova and cinder as
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scheduler hints.
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Enabling the scheduler hints
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----------------------------
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By default, passing the lifecycle scheduler hints is disabled. To enable it,
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set stack_scheduler_hints to True in heat.conf.
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The hints
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---------
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When heat processes a stack, and the feature is enabled, the stack id, root
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stack id, stack resource uuid, stack resource name, and the path in the stack
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(as a list of comma delimited strings of stackresourcename and stackname) will
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be passed by heat to nova and cinder as scheduler hints.
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Purpose
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-------
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A heat provider may have a need for custom code to examine stack requests
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prior to performing the operations to create or update a stack. After the
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custom code completes, the provider may want to provide hints to the nova
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or cinder schedulers with stack related identifiers, for processing by
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any custom scheduler plug-ins configured for nova or cinder.
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