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From Patrick Hunt <ph...@apache.org>
Subject Re: Growing a cluster
Date Thu, 05 May 2011 16:28:32 GMT
Hi Jared, you can go from 1 to 2+ nodes just fine:

1) change the configuration of server 1 from standalone to quorum
based (be sure to list the new members of the ensemble)
2) add a myid file for server 1
3) setup new servers 2+
4) restart server 1
5) start servers 2+

At this point the quorum should just come up. I just tried this
example and it worked fine for me going from 1 to 3 (the data I
created in standalone was available once I started the ensemble).

Regards,

Patrick

2011/5/5 Jared Cantwell <jared.cantwell@gmail.com>:
> Great information guys-- this helps me understand what needs done when
> expanding from 2 nodes to X nodes.
>
> Does anyone have insight on going from 1 node to 3 nodes?
>
> ~Jared
>
> 2011/5/5 Chang Song <tru64ufs@me.com>
>
>>
>> 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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