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From "Murali Krishna. P" <muralikpb...@yahoo.com>
Subject Re: Changing hosts
Date Thu, 12 May 2011 15:15:47 GMT
Thanks for the suggestion, but I had already started the process which Alex had mentioned and
DEF is started with ABC. How can we know whether DEF is synced ? the data/version-2 dir is
empty, i guess i need to wait till it gets some data there?

Murali Krishna

From: Vishal Kher <vishalmlst@gmail.com>
To: user@zookeeper.apache.org; Murali Krishna. P <muralikpbhat@yahoo.com>
Sent: Thursday, 12 May 2011 7:24 PM
Subject: Re: Changing hosts


Since you can stop clients, another way to achieve what Alex suggested is to:

1. stop clients
2. stop all current zk servers (a_i)
3. scp -r /etc/zookeeper/ from a_i to b_i
4. scp -r /var/zookeeper/ from a_i to b_i
5. On all b_i, edit /etc/zookeeper/zoo.cfg to reflect the correct IP addresses
5 start all b_i

This is assuming that stopping ZK server is ok in our environment.


On Thu, May 12, 2011 at 2:07 AM, Murali Krishna. P <muralikpbhat@yahoo.com> wrote:

Thanks for the responses,
>     I have the luxury of stopping the clients during the operations. So, I would
go with the second approach of cloning.
>Murali Krishna
>From: Ted Dunning <ted.dunning@gmail.com>
>To: Alexander Shraer <shralex@yahoo-inc.com>
>Cc: "user@zookeeper.apache.org" <user@zookeeper.apache.org>; Murali Krishna. P <muralikpbhat@yahoo.com>;
"zookeeper-user@hadoop.apache.org" <zookeeper-user@hadoop.apache.org>
>Sent: Thursday, 12 May 2011 5:27 AM
>Subject: Re: Changing hosts
>I think that this process does a slightly different thing.  Your process is good for
cloning a cluster, but it doesn't address the problem of transitioning a working cluster.
 My process never has two clusters with the same data so all transactions will always be
applied to a single notional version of the data.
>The reason that this is important is a part of the process that neither of us mentioned.
 That is how to transition the clients.  My assumption is that before the transition, all
clients would re-open their ZK connection with all 6 nodes in the list of servers.  Once
this is done, my process will lead the clients through the transition in a way that all updates
will be visible to all clients.  At the end, the clients should (eventually) trim their list
of servers to the shorter list of new servers.
>With a cluster clone operation, there will be moments when some clients connect to one
cluster and some connect to the other.  That makes it hard to understand how this will work
>The OP can probably clarify which task they really wanted to accomplish.
>On Wed, May 11, 2011 at 4:49 PM, Alexander Shraer <shralex@yahoo-inc.com> wrote:
>Hi Ted,
>>There's a simpler way that works. Suppose that the original servers are A, B and C,
and the new ones
>>are D, E, F. Configure D, E and F to be in the configuration A, B, C, D, E, F and
start them. Don't do any changes to
>>A, B and C. After D, E and F synch with the leader (or at least 2 of them do), turn
them off, change their config files to D, E, F and bring them up again.
>>> -----Original Message-----
>>> From: Ted Dunning [mailto:ted.dunning@gmail.com]
>>> Sent: Tuesday, May 10, 2011 8:39 AM
>>> To: user@zookeeper.apache.org; Murali Krishna. P
>>> Cc: zookeeper-user@hadoop.apache.org
>>> Subject: Re: Changing hosts
>>> Step 1:  configure two of the new hosts to be part of a 5 node cluster
>>> containing all of the
>>> original nodes.
>>> Step 2:  reconfigure each of the original 3 nodes to be part of the the
>>> 5
>>> node cluster.
>>> Step 3: bounce each of the originals and start the two new servers.
>>> Step 4: configure the 6th server (previously untouched) to be part of a
>>> three node cluster
>>> containing only the 3 new nodes.
>>> Step 5: reconfigure servers 4 and 5.
>>> Step 6: bounce servers 4 and 5 and start server 6.
>>> Done.
>>> (wait for somebody else to critique this procedure before proceeding
>>> with
>>> it)
>>> On Tue, May 10, 2011 at 7:54 AM, Murali Krishna. P
>>> <muralikpbhat@yahoo.com>wrote:
>>> > Hi,
>>> >      I have a zookeeper cluster (3.2.2) with 3 hosts. I need to
>>> replace all
>>> > the 3 hosts with different machines. What is the best way to achieve
>>> this
>>> > without any data loss? I can shutdown my clients during this
>>> operation.
>>> >
>>> >
>>> >
>>> > Thanks,
>>> > Murali Krishna
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