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From Akila Ravihansa Perera <raviha...@wso2.com>
Subject Re: [Discuss] Cloud Controller Clustering Model
Date Thu, 27 Nov 2014 02:37:10 GMT
Hi Imesh,

Thank you for the explanations.

I'm +1 for the overall model.

Thanks.
On 27 Nov 2014 07:19, "Imesh Gunaratne" <imesh@apache.org> wrote:

> Hi,
>
> On Wed, Nov 26, 2014 at 5:27 PM, Udara Liyanage <udara@wso2.com> wrote:
>
>> Reading from registry frequently might be more expensive than distributed
>> locking since a number of database queries are executed.
>> +1 for distributed collections.
>>
>> Are we going to use Hazlecast or any other framework ?
>>
>
> We are planning to use Carbon clustering (abstraction) which internally
> use Hazelcast.
>
> On Wed, Nov 26, 2014 at 5:30 PM, Akila Ravihansa Perera <
> ravihansa@wso2.com> wrote:
>
>>
>>> We don't have to refresh the whole data structure, but only the
>> invalidated object(s). We have to have a good registry structure for the
>> topology in order for this to be effective.
>>
>
> A distributed map does this OOB.
>
>>
>>
>>> - If above happens, when serving multiple requests (with a high
>>> frequency) on different instances of CC, the system might come to an
>>> inconsistent state because the in memory data structures have not updated
>>> properly.
>>>
>>
>> Good point, thanks for pointing out. But the same problem will occur when
>> using cluster messages to replicate the state, right? I guess we will have
>> to resort to a distributed lock in either case to avoid consistencies. I
>> remember Isuru was working on a hierarchical locking approach for the
>> topology. Perhaps we can incorporate that for this scenario as well.
>>
>
> We actually don't use cluster messages with a distributed map. However yes
> in either approach we will need a distributed lock. Indeed, for topology we
> should be able to change the existing locks to distributed ones if
> clustering is enabled.
>
>>
>> If you're going to use a distributed map, how do you plan to utilize that
>> to distribute the topology data structure? I think replicating the complete
>> topology object on change would be very expensive, wdyt?
>>
>> No, by design it will only send the modifications.
>
> Thanks
>
>
>
> --
> Imesh Gunaratne
>
> Technical Lead, WSO2
> Committer & PMC Member, Apache Stratos
>

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