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Zookeeper >> mail # user >> adding/removing a zookeeper server


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Mohammad Abdul-Amir 2012-04-26, 21:46
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Jordan Zimmerman 2012-04-26, 21:48
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Mohammad Abdul-Amir 2012-04-26, 22:55
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Alexander Shraer 2012-04-30, 06:32
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Mohammad Abdul-Amir 2012-04-30, 18:49
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Jordan Zimmerman 2012-04-30, 18:54
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Mohammad Abdul-Amir 2012-04-30, 19:10
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Re: adding/removing a zookeeper server
exactly - ZK-107 allows fully automatic reconfiguration without any
restarts (it adds this as an API command to zookeeper). We also have a
mechanism to rebalance clients across the new set of servers.

Currently you can do a rolling restart to change the configuration,
which is quite tricky to do correctly, but I believe that Jordan's
Exhibitor tool simplifies the process.

Alex

On Mon, Apr 30, 2012 at 11:54 AM, Jordan Zimmerman
<[EMAIL PROTECTED]> wrote:
> Technically, ZK does not support it. However, there is a methodology for
> reconfiguring and updated an ensemble. I believe ZK-107 will allow the
> changes to be made without needing to restart/reconfigure the cluster.
>
> -JZ
>
> On 4/30/12 11:49 AM, "Mohammad Abdul-Amir (Shamma)"
> <[EMAIL PROTECTED]> wrote:
>
>>Alex,
>>
>>It sounds like you are suggesting that zookeeper keeper does not support
>>adding/removing servers non-dynamically. If so, this contradicts with the
>>FAQ #6 that Jordan Zimmerman pointed out.
>>
>>On Sun, Apr 29, 2012 at 11:32 PM, Alexander Shraer
>><[EMAIL PROTECTED]>wrote:
>>
>>> Hi Mohammad,
>>>
>>> Support for adding/removing servers as well as dynamic changes to
>>> other parameters will be added as part of ZOOKEEPER-107, hopefully in
>>> the 3.5.0 release.
>>>
>>> Thanks,
>>> Alex
>>>
>>> On Thu, Apr 26, 2012 at 3:55 PM, Mohammad Abdul-Amir (Shamma)
>>> <[EMAIL PROTECTED]> wrote:
>>> > On Thu, Apr 26, 2012 at 2:48 PM, Jordan Zimmerman <
>>> [EMAIL PROTECTED]>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)"
>>> >> <[EMAIL PROTECTED]> 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)
>>>
>>
>>
>>
>>--
>>Mohammad Abdul-Amir (Shamma)
>