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From Michael Han <h...@cloudera.com>
Subject Re: How to add nodes to a Zookeeper 3.5.3-beta ensemble with reconfigEnabled=false
Date Fri, 23 Jun 2017 05:18:20 GMT
reconfigEnabled only disables reconfig command when reconfigEnabled=false;
it does not disable the feature by mute all code paths of the reconfig
feature introduced in ZOOKEEPER-107. So regardless of the value of
reconfigEnabled,
3.5.x ZK will create static config file and dynamic config file in any
cases.

This might create a problem for users who want to do rolling upgrade the
old way - because now the critical config information is not stored in
zoo.cfg anymore and modifying cfg.dynamic file manually will not work
because a reconfig needs to go through quorum processors. I think this is
the problem described in the thread.

Alex, is reconfig compatible with rolling upgrade? I don't find anything
mentioned in ZOOKEEPER-107 about this. Currently I think the answer is no,
which means for 3.5.x the only way to change membership of cluster is
through reconfig. Could you confirm this conclusion? If that is the case we
need patch the reconfigEnabled so it completely disable all code path of
the reconfig feature to leave the static zoo.cfg intact.


On Thu, Jun 22, 2017 at 9:35 PM, Alexander Shraer <shralex@gmail.com> wrote:

> This sounds like a bug in the implementation of reconfigEnabled.
> Could you please open a JIRA with the description you provided ?
>
> Out of curiosity, why do you disable reconfig ? It is intended exactly
> to perform the changes you're trying to make, in a simple and correct way.
>
> Thanks,
> Alex
>
> On Thu, Jun 22, 2017 at 3:17 PM, Guillermo Vega-Toro <gvegator@us.ibm.com>
> wrote:
>
> > I'm still unable to make configuration changes when reconfigEnabled=false
> > by updating zoo.cfg and restarting the servers.
> >
> > For example, I want to change the weight of one of my servers. I edit
> > zoo.cfg on the server I want to change, and specify the group, server.x,
> > and weight.x properties for all servers. I also remove the
> > dynamicConfigFile property and delete the dynamic config file. I then
> > restart the server. As soon as the server starts, the dynamic config file
> > re-appears, and it has the last configuration, as if the changes I made
> in
> > zoo.cfg were ignored. The dynamic configuration file on the other servers
> > also stays the same.
> >
> > What would be the correct way to achieve this (change a server's weight,
> > or role) when reconfigEnabled=false and the CLI reconfig command cannot
> be
> > used?
> >
> > Thanks
> >
> >
>



-- 
Cheers
Michael.

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