zookeeper-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Camille Fournier <cami...@apache.org>
Subject Re: observer changing to participant when there is no quorum
Date Tue, 14 Jun 2016 22:17:02 GMT
I'm finding the documentation quite confusing. I was under the impression
that quorum of some sort was needed to do a reconfig. Can you reconfig when
there is no quorum?

*Progress guarantees:* Up to the invocation of the reconfig operation, a
quorum of the old configuration is required to be available and connected
for ZooKeeper to be able to make progress. Once reconfig is invoked, a
quorum of both the old and of the new configurations must be available.

*Adding servers:* Before a reconfiguration is invoked, the administrator
must make sure that a quorum (majority) of participants from the new
configuration are already connected and synced with the current leader.



On Tue, Jun 14, 2016 at 5:35 PM, Alexander Shraer <shralex@gmail.com> wrote:

> This is needed only in case the target config doesn't have a quorum which
> are already followers in the old config
> and are up. We need agreement from a quorum of the target config, but
> observers aren't participating
> in the voting protocol.
>
> On Tue, Jun 14, 2016 at 7:35 PM, Michael Han <hanm@cloudera.com> wrote:
>
> > This might help:
> > https://zookeeper.apache.org/doc/trunk/zookeeperReconfig.html section
> > '*Changing
> > an observer into a follower:'*
> > "first invoke a reconfig to remove D from the configuration and then
> invoke
> > a second command to add it back as a participant (follower)."
> >
> >
> > On Tue, Jun 14, 2016 at 8:53 AM, Nomar Morado <nomar.morado@gmail.com>
> > wrote:
> >
> > > Hi
> > >
> > > I was trying to promote an observer into participant when ZK loses
> > quorum -
> > > but it seems that it does not allow to.
> > >
> > > Would you know how this can be accomplished without having to recycle
> ZK?
> > >
> > > I am using 3.5.0-alpha
> > >
> > >
> > > Thanks.
> > >
> >
> >
> >
> > --
> > Cheers
> > Michael.
> >
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message