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From Jordan Zimmerman <jzimmer...@netflix.com>
Subject Re: Missing session state handling in most Leader Election implementations
Date Mon, 14 Nov 2011 00:28:52 GMT
On 11/13/11 3:40 PM, "Jérémie BORDIER" <jeremie.bordier@gmail.com> wrote:

>As noticed in ZOOKEEPER-1209, this can cause really important issues.
>As Leader election is one of the most demanded feature / recipe, I
>would really like to see the official recipe fixed and fully
>functional.

Curator handles this in its API. Our LeaderSelector takes a listener
instance that has two methods:
    public void         takeLeadership(CuratorFramework client) throws
Exception;

    public void         notifyClientClosing(CuratorFramework client);

The second method is the important one here. You can think of this like
the JDK's thread interruption mechanism. If a split brain occurs, the
leader connected to the bad half will have its notifyClientClosing method
called.


BTW - all of our recipes have this kind of mechanism.

-JZ


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