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From elastic search <elastic....@gmail.com>
Subject Re: zk config 3.4.6
Date Mon, 07 Dec 2015 23:42:12 GMT
Thanks much for posting that link.

We have a read mostly zk setup . Considering that how should i proceed with
the migration.
say from ABC to DEF
1. Add  host D  to the server list  [ ABCD ]
2. Restart
3. Remove A  [ BCD ]
4. Restart
Till ABC gets replaced with DEF

Alternatively
Set up DEF as a seperate cluster of its own
Set up cnames that point  z1 ,z2 ,z3 to  A and D , B and E, and C and F
respectively
Add them to the zk client library
Restart the client to pick up the cname
At the point of release Remove cname entry to multiple hostnames and
restart of clients.

Any other ideas ?


On Mon, Dec 7, 2015 at 12:50 PM, Jordan Zimmerman <
jordan@jordanzimmerman.com> wrote:

> My personal advice is to config the ensemble as you want it and just deal
> with the down time. Rolling restarts can get messy. See here:
> http://zookeeper-user.578899.n2.nabble.com/Rolling-config-change-considered-harmful-td7578761.html
>
>
>
> > On Dec 7, 2015, at 3:46 PM, elastic search <elastic.l.k@gmail.com>
> wrote:
> >
> > So i was wondering what approach would be the desirable in terms of
> > downtime for the manual reconfiguration
> > Add all the 6 servers to the config . Bring up the 6 node Zk ensemble
> > Once done remove the 3 old servers from all the config
> > Restart followers
> > Restart leader
> >
> > I think a rolling restart would not work here correct ? I would need to
> > bring down the whole ensemble and then start up with the 3 new nodes
> >
> > On Mon, Dec 7, 2015 at 8:32 AM, Jordan Zimmerman <
> jordan@jordanzimmerman.com
> >> wrote:
> >
> >> It’s not possible. Prior to 3.5.x config changes require instance
> >> restarts. Once you restart the leader instance the ensemble will be
> >> unavailable for a short period of time until a new election.
> >>
> >> -Jordan
> >>
> >>> On Dec 7, 2015, at 11:31 AM, elastic search <elastic.l.k@gmail.com>
> >> wrote:
> >>>
> >>> In zookeeper 3.4.6 how do i add and remove servers in zoo.cfg without
> >>> affecting the cluster availability.
> >>>
> >>> For example
> >>> server.1=zoo1:2888:3888
> >>> server.2=zoo2:2888:3888
> >>> server.3=zoo3:2888:3888
> >>>
> >>> Step 1  : Add 4th server in config
> >>> server.1=zoo1:2888:3888
> >>> server.2=zoo2:2888:3888
> >>> server.3=zoo3:2888:3888
> >>> server.4=zoo3:2888:3888
> >>>
> >>> Step 2  : Remove 1st server in config
> >>> server.2=zoo2:2888:3888
> >>> server.3=zoo3:2888:3888
> >>> server.4=zoo3:2888:3888
> >>>
> >>> Up until the old servers have been replaced
> >>> server.4=zoo2:2888:3888
> >>> server.5=zoo3:2888:3888
> >>> server.6=zoo3:2888:3888
> >>>
> >>> As soon as the config change the servers become unusable . Please
> suggest
> >>
> >>
>
>

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