Setting up a MongoDB replica set

• All nodes have to be started with this flag --replSet "clusterName"
• In one of the nodes, execute the following commands

  $ mongo
  > rs.initiate()
  > rs.add("hostname1")
  > rs.add("hostname2")
  

• This command will allow you to execute queries in a slave node

  > rs.slaveOk()
  

• This command will show you the status of the cluster

  > rs.status()