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From Ted Dunning <ted.dunn...@gmail.com>
Subject Re: Changing hosts
Date Thu, 12 May 2011 17:17:46 GMT
I should have added this:

http://zookeeper.apache.org/doc/r3.1.2/zookeeperAdmin.html#sc_zkCommands

<http://zookeeper.apache.org/doc/r3.1.2/zookeeperAdmin.html#sc_zkCommands>to
explain what I meant by that.  I meant to say "when you send the 'stat'
command, what do you get"?

On Thu, May 12, 2011 at 10:16 AM, Ted Dunning <ted.dunning@gmail.com> wrote:

> When you ask each of the new nodes what their status is, what do they say?
>
>
> On Thu, May 12, 2011 at 9:09 AM, Murali Krishna. P <muralikpbhat@yahoo.com
> > wrote:
>
>> Hi,
>>      even after 1 hour, the version-2 dir seems to be empty on all 3 new
>> nodes. Can i just copy the last log.x and last snapshot.x file from
>> corresponding old nodes and bounce new nodes with new config?
>>
>>
>> Thanks,
>> Murali Krishna
>>
>>
>> ________________________________
>> From: Murali Krishna. P <muralikpbhat@yahoo.com>
>> To: Vishal Kher <vishalmlst@gmail.com>; "user@zookeeper.apache.org" <
>> user@zookeeper.apache.org>
>> Sent: Thursday, 12 May 2011 8:45 PM
>> Subject: Re: Changing hosts
>>
>> 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?
>>
>>
>> Thanks,
>> 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
>>
>>
>> Hi,
>>
>> 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.
>>
>> -Vishal
>>
>>
>> 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.
>> >
>> >
>> >Thanks,
>> >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
>> >
>> >
>> >
>> >Alex,
>> >
>> >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 well.
>> >
>> >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.
>> >>
>> >>Alex
>> >>
>> >>
>> >>
>> >>
>> >>
>> >>> -----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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