Nodes not seeing each other symmetrically


We had a weird bug with our production ES cluster this afternoon : we have
3 nodes, and each of those 3 was aware of exactly one other node : when
asking each node what other node(s) he knew of (with the _nodes API
endpoint), I got that:

  • 1 saw only 3
  • 2 saw only 1
  • 3 saw only 1

How is that possible? I would have thought that if a server A was aware of
another B, that then B would also be aware of A?

Rebooting 2 solved the issue, but I'm a bit worried about this happening

Thanks for your help,


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