openstack/glance-specs
Code Issues Proposed changes

Introduce Glance Taskflow stopfile feature

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Add lite-spec for a stopfile feature to prevent task processing.
The feature should operate similarly to existing code within
OpenStack.

Change-Id: I1ee3904a37adbbc700eecbbe131e53694eb17903
This commit is contained in:
Steve Lewis 2017-03-07 15:38:26 -08:00 committed by Steve Lewis (stevelle)
parent 9dcdb915c0
commit c0a5dd0eda
1 changed files with 32 additions and 0 deletions
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32
specs/pike/approved/glance/lite-specs.rst
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@ -133,5 +133,37 @@ Introduce db sync --check feature
End of `Introduce db sync --check feature`
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Introduce Glance Taskflow stopfile feature
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:problem: When preparing to take a Glance node down for maintenance or upgrade
it is necessary to allow long-running operations to complete without
allowing new operations to begin. The Taskflow engine does not have
the capability to prevent individual executors from starting new
jobs, and so attempting to take a Glance node out of the Taskflow
processing pool risks a race condition with that executor starting a
job just before the service is terminated which could cause the Task
processing to fail.
:solution: Introduce a disable_by_file_path feature to Glance Taskflow which
will prevent the node from picking up new jobs. This allows an
operator or automation engine to ``touch`` the appropriate file
before terminating the service. This feature should depend on the
oslo healthcheck middleware configuration to disable the taskflow
engine. As an additional impact, this work will require Glance to
instantiate a single taskflow engine as a singleton and reuse that
engine instance on all subsequent taskflow operations.
:impacts: None
:timeline: Expected to have a fix merged in the Pike cycle before milestone 2.
:link: https://docs.openstack.org/developer/oslo.middleware/healthcheck_plugins.html
:assignee: Unknown
End of `Introduce Glance Taskflow stopfile feature`
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Add your Spec Lite before this line
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