Elasticsearch

Elastic Stack Elasticsearch
1

hi
good day eveyone , why do we need 3 nodes in elasticsearch cluster for guarantee the high availibility and disaster recovery

2

Master election is based on majority decisions and only when you have 3 nodes or more can you form a strict majority without ALL nodes present. This allows a master to be elected even if one of the nodes is down.

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3

so if one of nodes is down the other node can elect another master right?

4

Yes, the other 2 nodes can form a majority and elect the master.

5

So, for example, if we have two nodes and one of them is disabled, could the remaining node elect itself?

6

No. The strict majority of 2 is 2, so both nodes are needed to elect a master. That is why 3 is the minimum.

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8

If any node goes down the remaining nodes will verify they can form a majority and elect a master if necessary.

9

thank you very much

10

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