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From chao chu <chuchao...@gmail.com>
Subject Re: Real world usage of the recipe LeaderLatch
Date Tue, 02 Jul 2013 16:29:16 GMT
sorry for the confusion. I knew that LeaderLatch will retry when it got
connection 'LOST' event and one of the participant should be elected as a
new leader when re-connected, however, I meant to ask *what if it stayed in
'LOST'* for quite a long time (for example, the zk ensemble become
unavailable). I can understand that how to handle this situation should be
very application specific, I was just trying to know what's your reaction
for this in your code (want to see if there are any ideas we can borrow).

not sure If i explained this clearly enough, thanks a lot for your reply
though.


On Tue, Jul 2, 2013 at 6:07 AM, Eric Tschetter <echeddar@gmail.com> wrote:

> My understanding is that LeaderLatch already handles those cases for you.
> The unit tests in TestLeaderLatch definitely have something that tries to
> test the LOST case.  If there's a case that is not handled, it'd probably
> be best if you could provide a unit test that shows what's not handled to
> help shape the conversation.
>
> --Eric
>
>
> On Fri, Jun 28, 2013 at 8:03 AM, chao chu <chuchao333@gmail.com> wrote:
>
>> Hi Eric,
>>
>> Thanks for your sharing, by looking into your code, it's not very clear
>> to me that how do you handle the 'SUSPEND' or 'LOST' events of LeaderLatch?
>> Could you please shed some lights here? Thanks
>>
>>
>> On Wed, Jun 26, 2013 at 11:52 PM, Eric Tschetter <echeddar@gmail.com>wrote:
>>
>>> ChuChao,
>>>
>>> We use it in the Druid project (http://www.github.com/metamx/druid/)
>>>
>>> You can see its use in the class com.metamx.druid.master.DruidMaster
>>>
>>> The class has a bunch of other stuff in it as well that is not specific
>>> to the LeaderLatch, but you can just ignore that and see how it handles the
>>> latch.
>>>
>>> --Eric
>>>
>>>
>>> On Wednesday, June 26, 2013, chao chu wrote:
>>>
>>>> Thanks a lot for your reply. Could you please name a few open source
>>>> projects that used LeaderLatch if you are aware of any? I'd like to take
a
>>>> look at the code.
>>>>
>>>> btw, What about issues reported in the links I mentioned? are they
>>>> actual bugs or just used in an unexpected way?
>>>>
>>>>
>>>>
>>>> On Wed, Jun 26, 2013 at 7:29 AM, Jordan Zimmerman <
>>>> jordan@jordanzimmerman.com> wrote:
>>>>
>>>>> Curator is being used at major companies (i.e. Netflix, eBay, etc.).
>>>>> Bugs are quickly fixed when reported. In particular, LeaderLatch is widely
>>>>> used.
>>>>>
>>>>> -JZ
>>>>>
>>>>>
>>>>> On Jun 25, 2013, at 11:03 AM, chao chu <chuchao333@gmail.com> wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> I have been trying to use the LeaderLatch to implement Leader Election
>>>>> in my project and had written some scripts to simulate the situations
when
>>>>> the zk ensemble become unstable due to network problems. It worked well
and
>>>>> as expected so far.
>>>>>
>>>>> However, by digging into both zookeeper-users and curator-users
>>>>> mailing lists, there are indeed some bugs/edge cases reported, like
>>>>> LeaderLatch bug causing extra znodes appearing in Zookeeper<https://groups.google.com/forum/?fromgroups#!searchin/curator-users/LeaderLatch/curator-users/to8ViZp6p-E/xYbKbzqkZQYJ>
>>>>>  and multiple participants thought they are leader<https://listserv.netflix.com/pipermail/curator-users/2012-October/000201.html>
which
>>>>> worried me about the reliability of this.
>>>>>
>>>>> So, my question is that: are there any real world projects are using
>>>>> this recipe which have proved the quality of it, or are there any other
>>>>> known edge cases or open issues?
>>>>>
>>>>>
>>>>> Thanks & Regards,
>>>>>
>>>>> --
>>>>> ChuChao
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> ChuChao
>>>>
>>>
>>
>>
>> --
>> ChuChao
>>
>
>


-- 
ChuChao

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