ES High Availability Requirements

[ninewb (Nick Newbill)]

Apologize for my novice questions.

I did an initial search and could not find this mentioned anywhere. I wanted to find some documentation or information to solidify my understanding in the required number of nodes for high availability. To assume this at a minimum:

3 master nodes (ive seen recommended, but thought 3 for HA was required)
2 data nodes

To dedicate masters, is the above true for the master nodes? Is 3 required?
I'd need 2 data nodes in case one fails.

Certainly understand that you can dedicate or have multiple roles for each all depending on your use cases and data ingest footprint. Assume in this situation the masters are dedicated and the data nodes are ingest, data, client.

[DavidTurner]

@ninewb

To dedicate masters, is the above true for the master nodes? Is 3 required?

Yes. Node | Elasticsearch Guide [8.11] | Elastic says:

To be able to remain available when one of the master-eligible nodes fails, clusters should have at least three master-eligible nodes, with minimum_master_nodes set accordingly.