Setup MongoDB Replication under 2 minutes

This guide is in continuation of MongoDB Replication: A complete installation guide where I explained how MongoDB replica set works and its step by step installation. You can visit the below link if you want to understand all steps:

MongoDB Replication: A complete installation guide

Here, we are going to run simple scripts to setup our MongoDB replica set which will:

• Install MongoDB
• Create admin user
• Create keyfile for security purposes
• edit mongo config file

Launch 3 AWS EC2 instances. I have launched Ubuntu instances for our replica set.

On primary node:

sh mongo-primary.sh DNS-address/Internal-IP replica-set-name

Note: Change password of admin user in script in line 22

On secondary nodes:

sh mongo-secondary.sh DNS-address/Internal-IP replica-set-name

Copy contents of /opt/mongo-keyfile file from primary node to secondary nodes and restart mongod service:

systemctl restart mongod

Start Replication and Add Members

connect to the Mongo with the admin user:

mongo -u admin -p --authenticationDatabase admin

Initiate the replica set:

rs.initiate()

add second and third nodes as a member:

rs.add("node-ip-address/DNS address")

Check the status of all nodes:

rs.status()

Replica set is ready to serve mongoDB. You can connect to it either by URI or MongoDB compass.

MongoDB Basic Commands

Create user:

db.createUser(
  {
    user: "test",
    pwd: "test123",
    roles: [ { role: "readWrite", db: "test" } ]
  }
)

Update user:

db.updateUser( "test",
               {
                 roles : ["clusterMonitor"]
                }
             )

Delete user:

db.dropUser("test")

Create Collection in a database:

db.createCollection("test_collection")

Comment if you have any queries. Stay tuned for more updates.