[openstack-dev] [Nova] Migration state machine proposal.
ndipanov at redhat.com
Wed Oct 14 08:53:50 UTC 2015
On 10/14/2015 04:29 AM, Tang Chen wrote:
>> On Wed, Oct 14, 2015 at 10:05 AM, Tang Chen <tangchen at cn.fujitsu.com
>> <mailto:tangchen at cn.fujitsu.com>> wrote:
>> Hi, all,
>> Please help to review this BP.
>> Currently, the migration_status field in Migration object is
>> indicating the
>> status of migration process. But in the current code, it is
>> by pure string, like 'migrating', 'finished', and so on.
>> The strings could be confusing to different developers, e.g. there
>> are 3
>> statuses representing the migration process is over successfully:
>> 'finished', 'completed' and 'done'.
>> And 2 for migration in process: 'running' and 'migrating'.
>> So I think we should use constants or enum for these statuses.
>> Furthermore, Nikola has proposed to create a state machine for the
>> which is part of another abandoned BP. And this is also the work
>> I'd like to go
>> on with. Please refer to:
This is IMHO a worthwhile effort on it's own. I'd like to see it use a
defined state machine in addition to being a simple enum so that
transitions are clearly defined as well.
>> Another proposal is: introduce a new member named "state" into
>> Use a state machine to handle this Migration.state, and leave
>> field a descriptive human readable free-form.
This is a separate effort IMHO - we should do both if possible.
> On 10/14/2015 11:14 AM, Zhenyu Zheng wrote:
>> I think it will be better if you can submit a spec for your proposal,
>> it will be easier for people to give comment.
> OK, will submit one soon.
If you plan to just enumerate the possible states - that should not
require a spec. Adding automaton in the mix, and especially adding a new
'state' field probably does deserve some discussion so in that case feel
free to write up a spec.
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