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https://issues.apache.org/jira/browse/SAMZA-1173?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16012928#comment-16012928
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Boris Shkolnik commented on SAMZA-1173:
---------------------------------------

The terminology is not defined yet.
We need to revisit this facility in general. 

I think we need to have the following coordination utilities:
1. LeaderElection
2. Latch
3. JobModelPublishing utility (including read, write and notifications)

They all should accept groupId parameter and may 

Some questions to resolve:
- do they have a separate connections to the ZK.
- do they work as a single pack of utilities (init and configed together).
- do they support reset/cleaup.
- separate register facility for each util.

> Evaluate CoordinationService design and resolve unresolved questions from 
> PR#91
> -------------------------------------------------------------------------------
>
>                 Key: SAMZA-1173
>                 URL: https://issues.apache.org/jira/browse/SAMZA-1173
>             Project: Samza
>          Issue Type: Bug
>            Reporter: Navina Ramesh
>            Assignee: Boris Shkolnik
>            Priority: Critical
>             Fix For: 0.14.0
>
>
> This JIRA is to address the shortcomings of the coordination service as it 
> stands today. We had some unresolved questions in the PR 
> [#91|https://github.com/apache/samza/pull/91]. There is also lack of clarity 
> on the requirements for this interface and the use-cases for it. These need 
> to be documented and discussed in a SEP. 
> Here are the open questions on this interface:
> 1. reset() method - what is purpose of this method? 
> 2. Need for the CoordinationService abstraction:
> bq. if there isn't any implementation for these method , can we please remove 
> them until we have a solid reason to add it? From what I understand, this 
> pluggable service doesn't enforce the user to use both leaderElector and 
> latch implementations. So, in such a case, adding "start" to initialize 
> certain environment doesn't seem correct. Will it be initialized with respect 
> to leader elector or processor? LeaderElector and Latch are their own 
> interfaces, anyway. What is the need to put them together in a 
> "CoordinationService" abstraction? Perhaps, @xinyuiscool can help you answer 
> that question
> 3. Cancelling leader election - Elaborate on why this is a required 
> feature/use-case for this api
> bq. @xinyuiscool what does "cancelling" a leader election mean when you are 
> within the context of "onBecomeLeader" ? Once a leader is chosen, you don't 
> have to cancel it. You simply need to add every one trying to become a leader 
> as a follower. Am I misunderstanding in your comment?



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