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Zookeeper, mail # user - leader election, scheduled tasks, losing leadership


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Eric Pederson 2012-12-09, 04:17
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Jordan Zimmerman 2012-12-09, 04:25
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Eric Pederson 2012-12-09, 04:49
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Jordan Zimmerman 2012-12-09, 04:52
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Eric Pederson 2012-12-09, 04:54
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Jordan Zimmerman 2012-12-09, 04:57
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Eric Pederson 2012-12-09, 04:56
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Re: leader election, scheduled tasks, losing leadership
Jordan Zimmerman 2012-12-09, 05:00
The leader latch lock is the equivalent of task in progress. I assume the task is running in the same VM as the leader lock. The only reason the VM would lose leadership is if it crashes in which case the process would die anyway.

-JZ

On Dec 8, 2012, at 8:56 PM, Eric Pederson <[EMAIL PROTECTED]> wrote:

> If I recall correctly it was Henry Robinson that gave me the advice to have
> a "task in progress" check.
>
>
> -- Eric
>
>
>
> On Sat, Dec 8, 2012 at 11:54 PM, Eric Pederson <[EMAIL PROTECTED]> wrote:
>
>> I am using Curator LeaderLatch :)
>>
>>
>> -- Eric
>>
>>
>>
>>
>> On Sat, Dec 8, 2012 at 11:52 PM, Jordan Zimmerman <
>> [EMAIL PROTECTED]> wrote:
>>
>>> You might check your leader implementation. Writing a correct leader
>>> recipe is actually quite challenging due to edge cases. Have a look at
>>> Curator (disclosure: I wrote it) for an example.
>>>
>>> -JZ
>>>
>>> On Dec 8, 2012, at 8:49 PM, Eric Pederson <[EMAIL PROTECTED]> wrote:
>>>
>>>> Actually I had the same thought and didn't consider having to do this
>>> until
>>>> I talked about my project at a Zookeeper User Group a month or so ago
>>> and I
>>>> was given this advice.
>>>>
>>>> I know that I do see leadership being lost/transferred when one of the
>>> ZK
>>>> servers is restarted (not the whole ensemble).   And it seems like I've
>>>> seen it happen even when the ensemble stays totally stable (though I am
>>> not
>>>> 100% sure as it's been a while since I have worked on this particular
>>>> application).
>>>>
>>>>
>>>>
>>>> -- Eric
>>>>
>>>>
>>>>
>>>> On Sat, Dec 8, 2012 at 11:25 PM, Jordan Zimmerman <
>>>> [EMAIL PROTECTED]> wrote:
>>>>
>>>>> Why would it lose leadership? The only reason I can think of is if the
>>> ZK
>>>>> cluster goes down. In normal use, the ZK cluster won't go down (I
>>> assume
>>>>> you're running 3 or 5 instances).
>>>>>
>>>>> -JZ
>>>>>
>>>>> On Dec 8, 2012, at 8:17 PM, Eric Pederson <[EMAIL PROTECTED]> wrote:
>>>>>
>>>>>> During the time the task is running a cluster member could lose its
>>>>>> leadership.
>>>>>
>>>>>
>>>
>>>
>>
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Henry Robinson 2012-12-09, 05:02
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Jordan Zimmerman 2012-12-09, 05:04
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Henry Robinson 2012-12-09, 05:12
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Jordan Zimmerman 2012-12-09, 05:18
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Henry Robinson 2012-12-09, 05:30
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Jordan Zimmerman 2012-12-09, 05:41
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Eric Pederson 2012-12-09, 21:42
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Eric Pederson 2012-12-09, 22:10
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Vitalii Tymchyshyn 2012-12-10, 06:49
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Eric Pederson 2012-12-10, 11:52
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Vitalii Tymchyshyn 2012-12-11, 20:09
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Eric Pederson 2012-12-12, 00:54
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Henry Robinson 2012-12-09, 04:59
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Eric Pederson 2012-12-09, 05:00