Adding nodes to an ensemble

[Jordan Zimmerman <jz...@netflix.com>]

It seems implicit in the docs that it's not possible to add nodes (even
Observers) to an existing ensemble without restarting each node in the
ensemble. i.e. The zoo.cfg has to be changed for each node. Is this true?
Is there any work being done on a broadcast protocol that doesn't require
static config?

-JZ

Re: Adding nodes to an ensemble

[Vishal Kher <vi...@gmail.com>]

Hi,

ZooKeeper allows you to add observers without restarting the voting members.
Try setting the id on each new observer to Long.MAX_VALUE and see if it
works.

PS: I have not tried this myself.

-Vishal

On Fri, Aug 12, 2011 at 3:53 PM, Alexander Shraer <sh...@yahoo-inc.com>wrote:

> Hi,
>
> Currently you have to restart the nodes to change the configuration
> (rolling restart, i.e., every time you bring nodes up after changing the cfg
> files you must ensure that a quorum of the old config intersects with any
> quorum of the new config). We're working on doing this dynamically and will
> hopefully add this feature to the next release after 3.4.  This allows to
> add/remove machines, change observers to followers and vice versa and change
> leader election and following ports, automatically without any restarts.
>
> Regards,
> Alex
>
> > -----Original Message-----
> > From: Jordan Zimmerman [mailto:jzimmerman@netflix.com]
> > Sent: Friday, August 12, 2011 11:21 AM
> > To: user@zookeeper.apache.org
> > Subject: Adding nodes to an ensemble
> >
> > It seems implicit in the docs that it's not possible to add nodes (even
> > Observers) to an existing ensemble without restarting each node in the
> > ensemble. i.e. The zoo.cfg has to be changed for each node. Is this
> > true?
> > Is there any work being done on a broadcast protocol that doesn't
> > require
> > static config?
> >
> > -JZ
>
>

RE: Adding nodes to an ensemble

[Alexander Shraer <sh...@yahoo-inc.com>]

Hi, 

Currently you have to restart the nodes to change the configuration (rolling restart, i.e., every time you bring nodes up after changing the cfg files you must ensure that a quorum of the old config intersects with any quorum of the new config). We're working on doing this dynamically and will hopefully add this feature to the next release after 3.4.  This allows to add/remove machines, change observers to followers and vice versa and change leader election and following ports, automatically without any restarts.

Regards,
Alex

> -----Original Message-----
> From: Jordan Zimmerman [mailto:jzimmerman@netflix.com]
> Sent: Friday, August 12, 2011 11:21 AM
> To: user@zookeeper.apache.org
> Subject: Adding nodes to an ensemble
> 
> It seems implicit in the docs that it's not possible to add nodes (even
> Observers) to an existing ensemble without restarting each node in the
> ensemble. i.e. The zoo.cfg has to be changed for each node. Is this
> true?
> Is there any work being done on a broadcast protocol that doesn't
> require
> static config?
> 
> -JZ