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Date: Thu, 26 Apr 2012 15:55:58 -0700
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Subject: Re: adding/removing a zookeeper server
From: "Mohammad Abdul-Amir (Shamma)" <mohammadshamma@gmail.com>
To: user@zookeeper.apache.org
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On Thu, Apr 26, 2012 at 2:48 PM, Jordan Zimmerman <jzimmerman@netflix.com>wrote:

> See #6 in the FAQ: http://wiki.apache.org/hadoop/ZooKeeper/FAQ
>
>
Okay, it seems that a zookeeper "upgrade" is possible according to FAQ.

Does removing/decommissioning a zookeeper server fall under the notion of
"upgrade" though? Does "upgrade" apply to any zookeeper config update?


> Also, FYI, we recently open sourced a ZooKeeper supervisor app that makes
> these kinds of tasks simpler:
>
>        https://github.com/Netflix/exhibitor
>
> -Jordan
>
> On 4/26/12 2:46 PM, "Mohammad Abdul-Amir (Shamma)"
> <mohammadshamma@gmail.com> wrote:
>
> >Hello,
> >
> >I have been searching through the zookeeper documentation and the web for
> >information about reconfiguring a zookeeper ensemble. More precisely I am
> >interested in adding/removing zookeeper servers to/from a zookeeper
> >ensemble. Unfortunately, I could not find much information around,
> >therefore I am bringing up the issue on this list.
> >
> >My questions are:
> >
> >- Is there a safe procedure to add a zookeeper server to a zookeeper
> >ensemble?
> >- Is there a safe procedure to remove a zookeeper server from an existing
> >ensemble?
> >
> >Some posts I have read suggest that these operations are possible. The
> >described procedure is to rewrite a new zookeeper configuration to all
> >involved servers and to restart them. However, given that I could not find
> >any information about how to carry out these two operations in zookeeper's
> >documentation makes me nervous about relying on the described procedure.
> >
> >I would appreciate if anyone can point me to a different procedures to
> >carry out add/remove operations, or convince me that it is safe to use the
> >procedure described above. Safety for me is two-fold: zookeeper database
> >can not get corrupted (unusable), and state updates can not get lost.
> >
> >--
> >Mohammad Abdul-Amir (Shamma)
>
>


-- 
Mohammad Abdul-Amir (Shamma)

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