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Zookeeper >> mail # user >> Dynamic reconfiguration

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Re: Dynamic reconfiguration
there are just two supported types - participant and observer.
(participant can act as either follower or leader).

So you can either write participant or leave it unspecified (which means
participant by default). Also, since the ip is the same for all your ports
you don't have to write it twice.  All of these should work in the same way:

server.5=;2181 <>
server.5=;2181 <>

On Fri, Jul 27, 2012 at 5:25 PM, Jared Cantwell <[EMAIL PROTECTED]>wrote:

> Thanks Alex for the response.  Our current lines in the configuration look
> like this:
> server.5=;
> For the new servers is it ok for their entry to have "participant"?  Or
> should that be something different (e.g. "follower")?
> ~Jared
> On Fri, Jul 27, 2012 at 6:20 PM, Alexander Shraer <[EMAIL PROTECTED]>wrote:
>> Hi Jared,
>> Thanks for experimenting with this feature.
>> The idea is that new servers join as "non voting followers". Which means
>> that they act as normal followers but the leader ignores their votes since
>> they are not part of the current configuration. The leader only counts
>> their votes during the reconfiguration itself (to make sure a quorum of the
>> new config is ready before the new config can be committed/activated).
>> Defining them as observers is not a good idea, for example in your scenario
>> if they were observers they wouldn't be able to participate in the
>> reconfiguration protocol (which is similar to the protocol for committing
>> any other operation in which observers don't participate) and since we
>> don't have a quorum of followers in the new config that can ack,
>> reconfiguration would throw an exception (of
>> KeeperException.NEWCONFIGNOQUORUM type).
>> Of course if you intend them to be observers in the new config you can
>> define them as observers since their votes are not needed during reconfig
>> anyway.
>> You're right, the new servers must be able to connect to the old quorum.
>> At minimum, their file should contain the current leader, but
>> you can also copy the current configuration file to the new members if
>> you wish.
>> In addition, you should add a line for the member itself, so that server
>> F appears in F's config file (Its not important that the other new servers
>> appear in F's file, but it won't hurt either, so you can do a union of old
>> and new if you wish). The constructor of QuorumPeer checks that the server
>> itself is in the configuration its started with, otherwise its not going to
>> run. This check has always been there, but I'm thinking of possibly
>> changing it in the future.
>> As soon as F connects to the leader, its config file will be overwritten
>> with the current config file as part of the synchronization process.
>> Alex
>> On Fri, Jul 27, 2012 at 10:06 AM, Jared Cantwell <
>> [EMAIL PROTECTED]> wrote:
>>> Hi,
>>> We are testing integration with 3.5.0 and dynamic membership and I have a
>>> question.  If I have a current set of servers in my ensemble {A,B,C,D,E}
>>> and I want to reconfigure the ensemble to {D,E,F,G,H}, how should the
>>> dynamic config file on servers F,G,H be configured on startup?  Should
>>> they
>>> have the old ensemble, the new ensemble, or the union of both ensembles?
>>>  It seems like these new servers need to  know about the old quorum, but
>>> since they aren't part of it yet its not clear to me how they should be
>>> configured.  Should there be an intermediate configuration with F,G, and
>>> H
>>> as simply Observers?
>>> I can't find much documentation on this so I want to make sure I
>>> understand
>>> things correctly.
>>> Thanks!
>>> ~Jared