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From Ted Dunning <ted.dunn...@gmail.com>
Subject Re: Changing hosts
Date Thu, 12 May 2011 17:16:22 GMT
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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