Docker is an open-source platform designed to automate the deployment, scaling, and management of applications using containerization. Containers allow developers to package an application with all its dependencies into a single unit that can run consistently across different environments.
| Term | Description |
|---|---|
| Image | A lightweight, standalone, and executable software package that includes everything needed to run a piece of software (code, runtime, libraries). |
| Container | A runtime instance of an image. Containers are isolated and portable. |
| Dockerfile | A text file that contains instructions to build a Docker image. |
| Docker Hub | A cloud-based registry service for sharing Docker images. |
# Build an image from a Dockerfile
docker build -t my-image-name .
# List local images
docker images
# Remove an image
docker rmi image-name# Run a container from an image
docker run -d -p 8080:80 --name my-container my-image
# List running containers
docker ps
# Stop a container
docker stop container-name
# Remove a container
docker rm container-name# Use official Node.js image as base
FROM node:18
# Set working directory
WORKDIR /app
# Copy dependencies
COPY package*.json ./
# Install dependencies
RUN npm install
# Copy app source code
COPY . .
# Expose port
EXPOSE 3000
# Run app
CMD ["node", "index.js"]A tool to define and run multi-container applications using a YAML file.
version: '3'
services:
web:
build: .
ports:
- "3000:3000"
db:
image: mongo
ports:
- "27017:27017"Run with:
docker-compose up# Create a volume
docker volume create my-volume
# Run a container with a volume
docker run -v my-volume:/data my-image- Use
.dockerignoreto exclude files from being copied to the image. - Use multi-stage builds to reduce image size.
- Keep containers stateless—use volumes for persistent data.
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