Last mongo replica set becomes secondary?

Question

I have 3 mongo nodes set up as replica sets. The following scenario is occurring:

• Node 1 is primary, node 2 is secondary, node 3 is secondary.
• Nodes 2 and

Answer 1

With a 3 node replicaset you need a minimum of 2 nodes up. The docs refer to a 'majority' required to elect a new primary. Therefore with a 3 node RS, there needs to be at least 2 nodes running for one node to be assigned as primary.

This page has a quite useful table showing the fault tolerance for replicasets with different numbers of nodes: https://docs.mongodb.org/manual/core/replica-set-architectures/