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From Chang Song <tru64...@me.com>
Subject Re: Growing a cluster
Date Thu, 05 May 2011 14:31:19 GMT

We are in a bit similar situation.

3 node -> 5 node ensemble.

The only way to do this is the following.

Assumption is that we have one DNS hostname for three zookeeper ensemble IP.
Since five node ensemble allows 2 node failure for quorum, we can do


0. First all two new ensemble IPs

1. change all three existing node config (zoo.cfg) and add two new node information
    Restart all three existing nodes in a sequence.

2. Replicate the new existing zoo.cfg to two new ensemble
    Start Zookeeper on two new server


You can do this in backward sequence (0 -> 2 -> 1) 
In your case, you can do 0 -> 2 -> 1, I think.

Chang



2011. 5. 5., 오후 9:57, Jared Cantwell 작성:

> It would be acceptable to me to do this non-dynamically and non-rolling as
> well. For example, I can shut down all nodes, make necessary modifications
> to config files, and then restart all nodes.  If I do this, should switching
> from standalone mode to multi-node mode work?  Has anyone done this before?
> Preliminary tests seem to work, but I haven't looked into all the race
> conditions and such yet.
> 
> ~Jared
> 
> On Thu, May 5, 2011 at 12:02 AM, Alexander Shraer <shralex@yahoo-inc.com>wrote:
> 
>> Hi Jared,
>> 
>> Currently there is no support for adding and removing zookeeper nodes
>> dynamically. See:
>> https://issues.apache.org/jira/browse/ZOOKEEPER-107
>> 
>> We're currently working to add this feature. However, AFAIK there is no
>> intention to support
>> transformation between standalone and multi-node modes, only membership
>> changes in multi-node mode.
>> 
>> Regards,
>> Alex
>> 
>> 
>>> -----Original Message-----
>>> From: Jared Cantwell [mailto:jared.cantwell@gmail.com]
>>> Sent: Wednesday, May 04, 2011 7:17 PM
>>> To: zookeeper-user@hadoop.apache.org
>>> Subject: Growing a cluster
>>> 
>>> Hello,
>>> 
>>> Say I was going to grow a cluster from 1 node to 3 nodes.  Is this
>>> possible,
>>> and what would be the recommended way?
>>> 
>>> At first I was thinking that I could go from 1 to 2 and then 2 to 3,
>>> and it
>>> seems to be working actually.  But I'm not sure if this is supported,
>>> mostly
>>> because in standalone mode the on-disk files are different than they
>>> are in
>>> a multi-node configurations.  Mutli-node configurations embed the
>>> quorum
>>> incarnation into the filename, which standalone does not.  Should a
>>> quorum
>>> node be able to startup using snapshots and logs that a standalone node
>>> wrote out?  Is there a way around this?
>>> 
>>> Thanks,
>>> Jared
>> 


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