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Behavior of 3 node Zookeeper quorum when 1 node fails

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Explorer

So I have noticed that operations can still continue when zookeeper fails 1 node of it's 3 node quorum although I understand that it can no longer accept writes because it has no leader (is this right). I know we have to satisfy the ceil(N/2) requirement, but this is to chose leadership it says nothing about how the dependencies (HBase in particular) would be affected.

 

My questions is at it's core, what is the behavior of zookeeper when failure is seen from 3 nodes to 2. Does it turn into a read only coordinator, as an immediate fix can one be assigned master?

 

Thanks.

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Thanks for your response and the documentation. I've read it more carefully now.

 

I have one more scenario to ask about: What does the failure of 2 zookeeper servers in a 3 server cluster imply?

 

  1. Does the final zookeeper server shutdown (not having a master to communicate with?) 
  2. Does the final zookeeper sever remain as a read only machine. 

I would appreciate if you could point me to documentation that also talked about this as well. 

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Explorer

Thanks, the link gives a 404 because there is a colon on the end, but I was still able to get there. 

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New Contributor

Zookeeper works on quorum. And quorum holds the majority of servers rules. If you have 3 servers and one is down, then Majority of servers are working. you can read further Zookeeper Quorum