Setup MongoDB Replica Set in 4 steps

Introduction

Before going into details of configuring MongoDB replica sets, let me give brief details about same:

Replica Set is the feature provided by the Mongodb database to achieve high availability and automatic failover.
It is kinda traditional master-slave configuration but have capability of automatic failover.
It is basically group/cluster of the mongod instances which communicates, replicates to each other to provide high availability and to do automatic failover
Basically, in replica sets there are minimum 2 and maximum of 12 mongod instances can exist
In replica set following types of server exist. out of all, one server is always primary.
- Primary: It stores the data, all write/read operation goes to this server from any client.
- Secondary: First it stores the data, second these servers stays in sync with primary, if primary server goes down then these servers are for failover to the primary.