In a recent project, I integrated Docker into our CI/CD pipeline to streamline the deployment of a microservices-based architecture across multiple environments. One of the primary challenges we faced was ensuring environment consistency between development, staging, and production environments. Docker solved this by enabling us to containerize the application and its dependencies, encapsulating everything in an isolated container that would run the same across all environments.

For example, here’s how we used a Dockerfile to containerize a simple Node.js application:
dockerfile
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Use official Node.js image as base

FROM node:14

Set the working directory inside the container

WORKDIR /app

Copy package.json and package-lock.json

COPY package*.json ./

Install dependencies

RUN npm install

Copy the rest of the application files

COPY . .

Expose port 3000

EXPOSE 3000

Start the application

CMD [“npm”, “start”]
And here’s how we used Docker Compose to manage multi-container applications (e.g., a Node.js app and MongoDB):
yaml
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version: ‘3.7’

services:
app:
build: .
ports:
– “3000:3000”
depends_on:
– mongo
mongo:
image: mongo:latest
volumes:
– ./data/db:/data/db

This Docker Compose file ensures that the app runs alongside a MongoDB service, and the configuration is consistent across environments.