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From kishore g <g.kish...@gmail.com>
Subject Re: Communicating Master config to Slave
Date Mon, 11 Mar 2013 06:12:29 GMT
Got it, that should work.

On Sun, Mar 10, 2013 at 11:01 PM, Ming Fang <mingfang@mac.com> wrote:

> Thanks Kishore.
> My use case requires starting a server socket when an instance becomes
> Master.
> Stop the server when that Master becomes Slave.
> And start a client socket when in Slave state.
> The Slave will have to lookup the Master's server socket info.
> I'm fairly far along with using HelixPropertyStore.
> One advantage I see is that using the PropertyStore I can set
> with AccessOption.EPHEMERAL option, which works for my use case.
> When I have time I'll look into the InstanceConfig option.
> Thanks again.
> On Mar 11, 2013, at 1:54 AM, kishore g <g.kishore@gmail.com> wrote:
> Hi Ming,
> InstanceConfig is the right choice. You can update this during start up,
> there is a callback interface called preConnectCallback, this is invoked
> after you connect to cluster but before liveInstance znode is created. You
> can set the config here using
> manager.getConfigAccessor().set(ConfigScope, key, value)
> See TestConfigAccessor on how to create ConfigScope, it basically allows
> you to set config at a cluster, instance, resource, partition level.
> Hope this helps.
> Thanks,
> Kishore G
> On Sun, Mar 10, 2013 at 9:42 PM, Ming Fang <mingfang@mac.com> wrote:
>> I have a use case similar to rsync-replicated-file-system recipe.
>> One difference is that my Master needs to communicate the server host and
>> port to the Slave.
>> Also the server port will be dynamic.
>> There seems to be three ways to communicate config changes to the Slave,
>> InstanceConfig, ConfigScope, and ZkHelixPropertyStore.
>> I actually don't know what ConfigScope is for.
>> InstanceConfig at first appears to the right place since it is the Master
>> instance config that is changing.
>> But there does not seem to be a way to update it once it is added the
>> Admin.
>> That leaves me with ZkHelixPropertyStore.
>> Is ZkHelixPropertyStore the best way to do this?
>> Thanks

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