Hi Supun,

I scheduled an arch review for this on Coming friday.

Few Qs

a) If two guys are editing the configurations and save it at the same
time, what do we do? I guess that is way you asked for a master?
b) What do we do if applying a update in a node failed due to some reason?
c) What happen to the message in transits while changes to the config
is being applied? I do not think we have to handle this in too much
details. But we have to know what going on and it is a likely Q from
customers when you mention this feature.

Thanks
Srinath

On Mon, Dec 6, 2010 at 6:32 AM, Sanjiva Weerawarana <[email protected]> wrote:
> +1 Supun but it seems to me we need to involve the load balancer in order to
> achieve this. We have to sort this out for Stratos' load balancer anyway as
> its critical to allow one tenant to upgrade something (for possibly just a
> few users) instead of forcing a global update.
> Sanjiva.
>
> On Sun, Dec 5, 2010 at 6:20 PM, Supun Kamburugamuva <[email protected]> wrote:
>>
>> I think we need a feature from registry based repo for doing this
>> successfully in a real production scenario.
>> In a production scenarion if there is a cluster of ESB's user don't want
>> to take down all the ESB's or update all the ESB's at the same time. Usually
>> when a change is made it is done in only one node. Then that node stays like
>> that for few days to make sure that the change is ok. During this time the
>> other nodes should act as previously. So for a production deployment we
>> shouldn't do automatic repository syncs for all the nodes by default.
>> User should be able to select when to sync with the registry repo. We can
>> provide an UI for doing this.
>> Here are the steps I think a user should follow to do a update in a
>> cluster.
>> 1. First user has to take the master node off the  traffic and update the
>> master node.
>> 3. After he thinks that the configuration is ok, enable the registry sync
>> in master node so that the registry is updated.
>> 2. Now when user want to do the change for a another ESB he has to take
>> that ESB out of traffic from load balancer and enable the registry sync.
>> This will update the configuration of that node.
>> Like wise user can do a successful configuration update without restarting
>> any of the machines.
>> Thanks,
>> Supun..
>>
>> On Sun, Dec 5, 2010 at 12:11 AM, Hiranya Jayathilaka <[email protected]>
>> wrote:
>>>
>>>
>>> On Sat, Dec 4, 2010 at 10:41 PM, Senaka Fernando <[email protected]> wrote:
>>>>
>>>>
>>>> On Sat, Dec 4, 2010 at 10:09 PM, Ruwan Linton <[email protected]> wrote:
>>>>>
>>>>> On 12/4/10 8:54 PM, Supun Kamburugamuva wrote:
>>>>>
>>>>> On Sat, Dec 4, 2010 at 5:45 PM, Sanjiva Weerawarana <[email protected]>
>>>>> wrote:
>>>>>>
>>>>>> On Sat, Dec 4, 2010 at 2:45 PM, Supun Kamburugamuva <[email protected]>
>>>>>> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>> The registry based repo, when enabled syncs the
>>>>>>> axis2 repository periodically. Basically it syncs what ever files that 
>>>>>>> are
>>>>>>> in the axis2 repository of a cluster of servers that are connected to a
>>>>>>> single configuration registry. It stores the files in to the registry 
>>>>>>> and
>>>>>>> then sync the file from there. Now we have moved the synapse 
>>>>>>> configuration
>>>>>>> to the axis2 repository as well. So when a synapse configuration file is
>>>>>>> modified the changes will be synched across the cluster. Because we 
>>>>>>> have hot
>>>>>>> update these changes will immediately taken in to account without 
>>>>>>> requiring
>>>>>>> a restart of the read-only nodes.
>>>>>>
>>>>>> Are we going to allow any node's config to be edited and have that
>>>>>> sync across all nodes or do we still have a master node concept?
>>>>>
>>>>> I think we should allow only the master node to be changed. There are
>>>>> some part of the configuration that doesn't work without this mode. For
>>>>> example we store things like security policy information about a service 
>>>>> in
>>>>> the registry. So in-order for these things to work user has to always 
>>>>> change
>>>>> the master node.
>>>>>
>>>>> Why?
>>>>
>>>> I see Master-node as a concept that we've introduced to overcome some of
>>>> the limitations we had in the past. If this model works, and if this is
>>>> expected to scale, we should not have a concept of a master-node in this
>>>> sense, as Ruwan points out. Somebody, needs to be the source of control, so
>>>> in that sense we could have a master.
>>>
>>> +1 and +1 to disabling registry persistence for Synapse configuration.
>>> With the new model old registry persistence becomes obsolete really.
>>> Thanks,
>>> Hiranya
>>>
>>>>
>>>> Thanks,
>>>> Senaka.
>>>>
>>>>>
>>>>> Any explanation why those changes has to be on the master node, what is
>>>>> special about the master node apart from the fact that it controls the
>>>>> configuration?
>>>>>
>>>>> Ruwan
>>>>>
>>>>> Thanks,
>>>>> Supun..
>>>>>
>>>>>>
>>>>>> I think we have some issues in Stratos because the registry repo is
>>>>>> synced on a timer. IIRC we discussed changing that to use registry 
>>>>>> eventing
>>>>>> to notify the subscribers and they'll pull the changes in. Have we
>>>>>> implemented that?
>>>>>> We need to avoid getting into a change loop as a result too .. but
>>>>>> we've dealt with that at a customer setup a while ago.
>>>>>> Sanjiva.
>>>>>> --
>>>>>> Sanjiva Weerawarana, Ph.D.
>>>>>> Founder, Chairman & CEO; WSO2, Inc.;  http://wso2.com/
>>>>>> email: [email protected]; phone: +94 11 763 9614; cell: +94 77 787 6880
>>>>>> | +1 650 265 8311
>>>>>> blog: http://sanjiva.weerawarana.org/
>>>>>>
>>>>>> Lean . Enterprise . Middleware
>>>>>>
>>>>>> _______________________________________________
>>>>>> Carbon-dev mailing list
>>>>>> [email protected]
>>>>>> https://wso2.org/cgi-bin/mailman/listinfo/carbon-dev
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Supun Kamburugamuva
>>>>> Technical Lead
>>>>> WSO2 Inc.;  http://wso2.org
>>>>> E-mail: [email protected];  Mobile: +94 77 431 3585
>>>>> Blog: http://supunk.blogspot.com
>>>>>
>>>>> _______________________________________________
>>>>> Carbon-dev mailing list
>>>>> [email protected]
>>>>> https://wso2.org/cgi-bin/mailman/listinfo/carbon-dev
>>>>>
>>>>>
>>>>> --
>>>>> Ruwan Linton
>>>>> Software Architect & Product Manager, WSO2 ESB; http://wso2.org/esb
>>>>> WSO2 Inc.; http://wso2.com
>>>>>
>>>>> Lean . Enterprise . Middleware
>>>>>
>>>>> phone: +1 408 754 7388 ext 51789
>>>>> email: [email protected]; cell: +94 77 341 3097
>>>>> blog: http://blog.ruwan.org
>>>>> linkedin: http://www.linkedin.com/in/ruwanlinton
>>>>> tweet: http://twitter.com/ruwanlinton
>>>>>
>>>>> _______________________________________________
>>>>> Carbon-dev mailing list
>>>>> [email protected]
>>>>> https://wso2.org/cgi-bin/mailman/listinfo/carbon-dev
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Senaka Fernando
>>>> Associate Technical Lead & Product Manager - WSO2 G-Reg;
>>>> WSO2, Inc.; http://wso2.com
>>>> Member; Apache Software Foundation; http://apache.org
>>>>
>>>> E-mail: senaka AT wso2.com
>>>> P: +1 408 754 7388; ext: 51736;
>>>> M: +94 77 322 1818
>>>> Linked-In: http://www.linkedin.com/in/senakafernando
>>>>
>>>> Lean . Enterprise . Middleware
>>>>
>>>>
>>>> _______________________________________________
>>>> Carbon-dev mailing list
>>>> [email protected]
>>>> https://wso2.org/cgi-bin/mailman/listinfo/carbon-dev
>>>>
>>>
>>>
>>>
>>> --
>>> Hiranya Jayathilaka
>>> Senior Software Engineer;
>>> WSO2 Inc.;  http://wso2.org
>>> E-mail: [email protected];  Mobile: +94 77 633 3491
>>> Blog: http://techfeast-hiranya.blogspot.com
>>>
>>> _______________________________________________
>>> Carbon-dev mailing list
>>> [email protected]
>>> https://wso2.org/cgi-bin/mailman/listinfo/carbon-dev
>>>
>>
>>
>>
>> --
>> Supun Kamburugamuva
>> Technical Lead
>> WSO2 Inc.;  http://wso2.org
>> E-mail: [email protected];  Mobile: +94 77 431 3585
>> Blog: http://supunk.blogspot.com
>>
>> _______________________________________________
>> Carbon-dev mailing list
>> [email protected]
>> https://wso2.org/cgi-bin/mailman/listinfo/carbon-dev
>>
>
>
>
> --
> Sanjiva Weerawarana, Ph.D.
> Founder, Chairman & CEO; WSO2, Inc.;  http://wso2.com/
> email: [email protected]; phone: +94 11 763 9614; cell: +94 77 787 6880 | +1
> 650 265 8311
> blog: http://sanjiva.weerawarana.org/
>
> Lean . Enterprise . Middleware
>
> _______________________________________________
> Carbon-dev mailing list
> [email protected]
> https://wso2.org/cgi-bin/mailman/listinfo/carbon-dev
>
>



-- 
============================
Srinath Perera, Ph.D.
  Senior Software Architect, WSO2 Inc.
  Visiting Lecturer, University of Moratuwa
  Member, Apache Software Foundation
  Research Scientist, Lanka Software Foundation
  Blog: http://srinathsview.blogspot.com/

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