C-D-theory

Containerized Web Application with PostgreSQL using Docker Compose and Macvlan

NAME:VAANI JINDAL

BATCH: 2(CCVT)

SAP:500119144

1. Introduction

This project demonstrates the containerization and deployment of a web application using Docker technologies. The application consists of a Node.js backend connected to a PostgreSQL database. Docker Compose is used to orchestrate the containers, while Docker networking concepts such as Macvlan and bridge networking are demonstrated.

The objective of the project is to understand containerized deployment, service orchestration, persistent storage, and networking using Docker.

2. Project Objectives

The main objectives of this project are:

Design a containerized web application
Use PostgreSQL as the database
Implement backend API using Node.js
Build Docker images using Dockerfiles
Use Docker Compose for multi-container orchestration
Demonstrate container networking concepts
Implement persistent storage using Docker volumes

3. Project Architecture

The system architecture consists of two containers:

Backend Container (Node.js + Express)
Database Container (PostgreSQL)

The backend communicates with the PostgreSQL container through a Docker network.

5. Backend Implementation

The backend is implemented using Node.js and Express.

The backend server connects to the PostgreSQL database using the pg library and provides an API endpoint.

This endpoint queries the database and returns the current time from PostgreSQL.

6. Dockerfile Implementation

Backend Dockerfile

The backend Dockerfile builds the Node.js application container.

Key steps include:

Using the Node.js base image
Installing dependencies
Copying application files
Exposing port 3000

Database Dockerfile

The PostgreSQL container is built using the official PostgreSQL image and configured using environment variables.

7. Docker Compose Configuration

Docker Compose is used to run multiple containers together.

The configuration defines:

Backend service
Database service
Docker network
Persistent volumes

8. Container Build Process

The following screenshot shows the container build process and service initialization.

Docker Build

9. Container Execution

The containers are started using Docker Compose.

The backend container starts the Node.js server and connects to PostgreSQL.

Container Startup

10. Running Containers

The following screenshot shows the running containers using the docker ps command.

Running Containers

11. Docker Network Inspection

Docker networks allow containers to communicate with each other.

The network inspection command used:

Screenshot:

Network Inspect

12. Container IP Address

Each container receives an IP address within the Docker network.

Screenshot showing container details:

Container IP

13. Volume Persistence Test

Docker volumes are used to persist database data even when containers are stopped or restarted.

Screenshot showing volume persistence:

Volume Persistence

14. Macvlan Network Creation

Macvlan networking allows containers to appear as physical devices on the network.

Screenshot:

Macvlan Network

15. Application Output

The backend successfully connects to PostgreSQL and returns the database timestamp.

Example output:

Screenshot:

Application Output

16. Image Size Comparison

Image	Approx Size
Node.js Base Image	~350 MB
PostgreSQL Image	~300 MB

Using optimized Docker builds helps reduce image size and improve deployment performance.

17. Macvlan vs Ipvlan Comparison

Feature	Macvlan	Ipvlan
IP per Container	Yes	Yes
Performance	High	Very High
Isolation	Strong	Moderate
Complexity	Moderate	Higher