[Pacemaker] Migration atomicity

[Vladislav Bogdanov]

15.03.2012 01:49, Andreas Kurz wrote:
> On 03/14/2012 08:40 AM, Vladislav Bogdanov wrote:
>> Hi,
>>
>> I'm observing a little bit unintuitive behavior of migration logic when
>> transition is aborted (due to CIB change) in the middle of the resource
>> migration.
>>
>> That is:
>> 1. nodea: migrate_to nodeb
>> 2. transition abort
>> 3. nodeb: stop
>> 4. nodea: migrate_to nodec
>> 5. nodec: migrate_from nodea
>> (note: no stop on nodea)
>>
>> While I expect migration operation pair to be "more atomic":
>> 1. nodea: migrate_to nodeb
>> 2. transition abort
>> 3. nodeb: migrate_from nodea
>> 4. nodea: stop
>> 5. nodeb: migrate_to nodec
>> 6. nodec: migrate_from nodeb
>> 7. nodeb: stop
>>
>> Is the current behavior intended?
> 
> You mean that a migration is rolled-back due to a transition abort --
> depending on its progress? I think that is the defined (and intended)
> behavior since quite a long time ... maybe Andrew likes to comment on that?

RA is very fast, it mostly operates on a pseudo-resource, so migrate_to
should be finished somewhere near transition abort (which is caused by
another resource which starts in the same time and modifies CIB).

And I do not see a roll-back (what can it mean?), I just see that
migration is broken in the middle.

Best,
Vladislav