users@shoal.java.net

Re: [Shoal-Users] Ceasing Leadership

From: Shreedhar Ganapathy <Shreedhar.Ganapathy_at_Sun.COM>
Date: Wed, 13 Feb 2008 08:50:32 -0800

I understand the obvious benefit but not all group comm libs provide the
facility to have a deterministic master chosen by the application.

The implementation on the lines you describe is already implemented by
Sheetal a few weeks ago, to help manage the situation where the master
is one of the core cluster members and that cluster is being shutdown by
a Spectator member who happens to be an admin application controlling
the lifecycle of the cluster.
This helped GlassFish use cases where planned shutdown notifications
were, as a result of this facility, more correctly disseminated.

I am interested in hearing from Shoal users like Alireza what other
specific use cases a facility of this sort helps. This will help us
differentiate Shoal's provider features from other implementations.

hth
Shreedhar

Mohamed Abdelaziz wrote:
> I can see the benefit of such feature.
>
> Alireza, it should be fairly straight forward to implement (1 day
> implementation, 1 day QA). It would entail an addition of a master
> node protocol message (to indicate a takeover action between two
> nodes, then followed by an assertion by the new master), and exposing
> the API's from the provider level up to the GMS level. Submit an
> issue along with a patch, we'll gladly consider the new feature.
>
>
> Mohamed
>
>
> Shreedhar Ganapathy wrote:
>> In a sense this exists as a forcible takeover API thereby allowing an
>> existing leader to relinquish its leader role.
>> I would be very interested in your use case though as it will help
>> make our documentation on intended uses for such a thing more clear.
>>
>> Sent from my phone
>>
>> On Feb 13, 2008, at 7:14 AM, Shreedhar Ganapathy
>> <Shreedhar.Ganapathy_at_Sun.COM <mailto:Shreedhar.Ganapathy_at_Sun.COM>>
>> wrote:
>>
>>> That's not something we found a need for. So it does not exist
>>> today. Is there use case where this would be useful? Thanks Shreedhar
>>>
>>> Sent from my phone
>>>
>>> On Feb 13, 2008, at 7:08 AM, Alireza Farhoush <alireza_at_tibco.com
>>> <mailto:alireza_at_tibco.com>> wrote:
>>>
>>>> Can a member relinquish its role as a leader without leaving its
>>>> group (assuming that there are more that one member of course)?
>>>>
>>>> Thanks,
>>>>
>>>> Alireza
>
>
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