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node.jsmongodbmongodb-replica-set

mongodb failover connection

I have a nodejs app that connects to mongodb.

Mongodb allows replicaset client connection to provide a level of resilience.

e.g "mongodb://localhost:50000,localhost:50001/myproject?replicaSet=foo", the client first connects to localhost@50000 and if that dies it switches to localhost@50001.

This is fine but if when the application starts and if one of the two mongo is dead then the application dies - with can't connect error.

The only solution I can think is to reformat the url so it excludes the inactive instance, but would like to avoid this ...

Any ideas?

Thanks

Solution

  • Replicaset works fine when do you have an odd number of servers, because MongoDB ReplicaSet work using election between nodes for define what server will be the "primary".

    You can to add a new node in your ReplicaSet just for voting. It's called "ARBITER".

    You can understand more about ReplicaSet Elections on this page https://docs.mongodb.com/manual/core/replica-set-elections/#replica-set-elections.