MongoDB Documentation  Release 3.0.4 7. To confirm the new configuration  call rs.conf() in the mongo shell. Your output should resemble: { "_id" : "rs"  "version" : 4  "members" : [ { "_id" : 0  "host" : "mongodb0.example.net:27017" }  { "_id" : 1  "host" : "mongodb1.example.net:27017" }  { "_id" : 2  "host" : "mongodb2.example.net:27017" } ] } Change All Hostnames at the Same Time This procedure uses the above assumptions (page 642). mongod --dbpath /data/db1/ --port 37017 mongo --port 37017 (b) Edit the replica set configuration manually. The replica set configuration is the only document in the system.replset collection in the local database. Edit the replica set configuration with the new hostnames and correct ports for all the members of the replica set. Consider the following sequence of commands to change the hostnames in a three-member set: (a) Open a mongo shell connected to the mongod running on the new  temporary port. For example  for a member running on a temporary port of 37017   you would issue this command: 3. For each member of the replica set  perform the following sequence of operations: 2. Restart each member on a different port and without using the --replSet run-time option. Changing the port number during maintenance prevents clients from connecting to this host while you perform maintenance. Use the member’s usual --dbpath   which in this example is /data/db1 . Use a command that resembles the following: 1. Stop all members in the replica set . Chapter 9. Replication 644 use local cfg = db.system.replset.findOne( { "_id": "rs" } ) cfg.members[0].host = "mongodb0.example.net:27017" cfg.members[1].host = "mongodb1.example.net:27017" cfg.members[2].host = "mongodb2.example.net:27017" db.system.replset.update( { "_id": "rs" }   cfg )