Installing MongoDB

Introduction

MongoDB is a popular open-source NoSQL database designed for modern applications that require scalability, flexibility, and high performance. It stores data in a document-oriented format, using JSON-like BSON (Binary JSON) objects. Unlike traditional relational databases, MongoDB is schema-less, which allows developers to handle dynamic, unstructured, or semi-structured data with ease.

Installing and configuring MongoDB

Connect to the MongoDB virtual machine (VM) using the SSH credentials specific to your environment. For Stackbill, the default operating system for VMs is Ubuntu 22.x, and the default username is ubuntu

Once logged in as the ubuntu user, switch to the root account for elevated privileges. Use the following command.

sudo -i

Go to the /usr/local/src directory, where all scripts will be stored as temporary location.

cd /usr/local/src

Download the MongoDB installation script from the centralized repository using the wget command.

wget https://stacbilldeploy.s3.us-east-1.amazonaws.com/MongoDB/Mongodb.sh

Provide executable permissions to the script

chmod +x Mongodb.sh

Execute the script to begin the MongoDB installation process

sh MongoDb.sh

The script will install all required MongoDB components and configure them. During the process, you’ll be prompted to set up an admin account. For our demo environment, we user username as stackbill and password MuyUzRc7t32R

After completing the configuration and admin user creation, the script will display the message "MongoDB configuration updated and admin user created successfully"

MongoDB Cluster Configuration

When deploying a production-grade Stackbill environment, a MongoDB cluster is recommended to ensure high availability, fault tolerance, and scalability. This setup uses three virtual machines (VMs): a primary node, a secondary node, and an arbiter. The arbiter helps in election processes without storing data, maintaining quorum during failover scenarios.

What is mean by arbiter?

A MongoDB cluster arbiter is a lightweight member of a MongoDB replica set that participates in the election process for determining the primary node in the cluster. However, it does not store data or serve client requests. The arbiter ensures high availability and fault tolerance by enabling the replica set to maintain a quorum during elections, especially in cases where the set contains an even number of data-bearing nodes.

Below are detailed steps to configure the MongoDB cluster.

In our testing environment, we set up three virtual machines named Mongo-01, Mongo-02, and Mongo-03. Mongo-01 serves as the primary node, Mongo-02 functions as the secondary node, and Mongo-03 acts as the arbiter.
Login into each VM and update and upgrade packages on all three VMs

apt update & apt upgrade -y

Reboot all VMs to apply updates.
On each VM, navigate to the /usr/local/src/ directory.

cd /usr/local/src/

Download the cluster-common.sh script on all three VMs.

wget https://stacbilldeploy.s3.us-east-1.amazonaws.com/MongoDB/cluster/cluster-common.sh

Make the script executable.

chmod +x cluster-common.sh

Execute the script.

sh cluster-common.sh

Once its completed it shows "MongoDB Installation completed Successfully"

Primary Node Configuration

On Mongo-01, download the cluster-primary-config.sh script

wget https://stacbilldeploy.s3.us-east-1.amazonaws.com/MongoDB/cluster/cluster-primary-config.sh

Make it executable

chmod +x cluster-primary-config.sh

Run the script

sh cluster-primary-config.sh

Provide the internal IP addresses and login credentials for Mongo-02 and Mongo-03.

Once the replication configuration is completed it shows the message as “ Files transferred and MongoDB service restarted on secondary and arbiter servers. Great job!”

Enable Replication in Primary Node

On Mongo-01, download the cluster-primary-replication.sh script.

wget https://stacbilldeploy.s3.us-east-1.amazonaws.com/MongoDB/cluster/cluster-primary-replication.sh

Make it executable

chmod +x cluster-primary-replication.sh

Execute the script

sh cluster-primary-replication.sh

Provide the private IPs of Mongo-01, Mongo-02, and Mongo-03 to configure replication.

During the replication process, the script will prompt for new MongoDB admin credentials. In this demo environment, we provide DB username as stackbill and password as MuyUzRc7t32R