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From Flavio Junqueira <...@yahoo-inc.com>
Subject Re: The idea behind 'myid'
Date Wed, 30 Sep 2009 09:14:48 GMT
We just need a unique identifier for every server. If such an  
identifier "magically" appears somehow, then I believe our protocols  
will be equally happy. Now, a mechanism to assign ids would also have  
to take into consideration the group scheme we have for hierarchical  
quorums. To assign servers to groups, we currently use the identifiers  
we assign manually to servers. If we don't have such identifiers, then  
we need a different way of configuring groups.


On Sep 29, 2009, at 7:01 PM, Patrick Hunt wrote:

> Jason Venner wrote:
>> I do find having to have a custom file in each zk root somewhat  
>> awkward, as
>> I like to rsync my configuration files around. I also would prefer  
>> not to
>> have to have all of my zk nodes listed in the configuration file by  
>> id.
>> I think I would prefer it if there was a mechanism for each log  
>> directory to
>> come up with a cluster unique id, and then the jvm running on that  
>> log dir
>> would advertise that ID.
> You are saying to list the server's ip/port in each of the server  
> config
> files, but not the id's, correct? The server id is actually used as  
> part
> of the quorum (zab) protocol - servers with lower id's don't attempt  
> to
> connect to servers with higher id when forming quorum (to avoid 2
> servers negotiating on 2 channels/threads). Perhaps this can be worked
> around though. Flavio?
> I'll enter a jira for tracking this feature as soon as apache issue
> tracking comes back (seems to be down right now).
>> If there was a control that would allow runtime changing of the  
>> required
>> quorum, then I could dynamically add and remove nodes.
> https://issues.apache.org/jira/browse/ZOOKEEPER-107
> Patrick
>> 2009/9/29 Ørjan Horpestad <orjanh@gmail.com>
>>> Thanks for all of your answers. I can see more clearly why using  
>>> an IP
>>> as id could be a bad idea in a ZK setup.
>>> Patrick:
>>> I will indeed try out your Zkconf tool, thanks.
>>> Regards, Orjan

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