How to Install and Use Docker on Linux in 2025: Complete DevOps Tutorial

Meta Description: Learn how to install and use Docker on Linux in 2025. Complete tutorial covering containerization, Docker Compose, images, and containers for DevOps professionals.

Introduction

Docker has revolutionized the way developers and DevOps professionals deploy applications through containerization technology. As we enter 2025, Docker remains the leading platform for creating, distributing, and running containerized applications on Linux systems. This comprehensive Linux Docker tutorial will guide you through everything from installation to advanced usage, making it perfect for both beginners and experienced professionals looking to master containerization.

Containerization has become essential in modern DevOps workflows, enabling consistent application deployment across different environments while maximizing resource efficiency. Whether you're developing microservices, setting up CI/CD pipelines, or managing complex applications, understanding Docker on Linux is crucial for success in today's tech landscape.

What is Docker and Why Use It on Linux?

Docker is a containerization platform that packages applications and their dependencies into lightweight, portable containers. Unlike traditional virtual machines, Docker containers share the host operating system's kernel, making them more efficient and faster to start.

Key Benefits of Docker on Linux:

- Resource Efficiency: Containers use fewer resources than virtual machines - Portability: Applications run consistently across different Linux distributions - Scalability: Easy horizontal scaling of applications - Isolation: Applications run in isolated environments - DevOps Integration: Seamless integration with CI/CD pipelines - Version Control: Easy application versioning and rollbacks

System Requirements and Prerequisites

Before installing Docker on your Linux system, ensure you meet these requirements:

Minimum System Requirements:

Supported Linux Distributions (2025):

Installing Docker on Linux

Method 1: Installing Docker on Ubuntu/Debian

First, update your package index and install prerequisites:

`bash sudo apt update sudo apt install apt-transport-https ca-certificates curl gnupg lsb-release `

Add Docker's official GPG key:

`bash curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg `

Add the Docker repository:

`bash echo "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null `

Install Docker Engine:

`bash sudo apt update sudo apt install docker-ce docker-ce-cli containerd.io docker-compose-plugin `

Method 2: Installing Docker on CentOS/RHEL/Fedora

Install required packages:

`bash sudo dnf install -y dnf-plugins-core `

Add Docker repository:

`bash sudo dnf config-manager --add-repo https://download.docker.com/linux/fedora/docker-ce.repo `

Install Docker:

`bash sudo dnf install docker-ce docker-ce-cli containerd.io docker-compose-plugin `

Method 3: Universal Installation Script

Docker provides a convenience script for quick installation:

`bash curl -fsSL https://get.docker.com -o get-docker.sh sudo sh get-docker.sh `

Post-Installation Setup

Start and Enable Docker Service

`bash sudo systemctl start docker sudo systemctl enable docker `

Add User to Docker Group

To run Docker commands without sudo:

`bash sudo usermod -aG docker $USER newgrp docker `

Verify Installation

`bash docker --version docker run hello-world `

Understanding Docker Images

Docker images are read-only templates used to create containers. They contain the application code, runtime, libraries, and dependencies needed to run an application.

Working with Docker Images

List available images:

`bash docker images `

Search for images on Docker Hub:

`bash docker search nginx `

Pull an image from Docker Hub:

`bash docker pull nginx:latest docker pull ubuntu:22.04 `

Remove an image:

`bash docker rmi nginx:latest `

Building Custom Images

Create a Dockerfile:

`dockerfile

Use official Python runtime as base image

Set working directory

Copy requirements file

Install dependencies

Copy application code

Expose port

Define command to run application

Build the image:

`bash docker build -t myapp:1.0 . `

Working with Docker Containers

Containers are running instances of Docker images. They provide isolated environments for applications.

Basic Container Operations

Run a container:

`bash docker run -d --name webserver -p 8080:80 nginx `

List running containers:

`bash docker ps `

List all containers (including stopped):

`bash docker ps -a `

Stop a container:

`bash docker stop webserver `

Start a stopped container:

`bash docker start webserver `

Remove a container:

`bash docker rm webserver `

Interactive Container Usage

Run container interactively:

`bash docker run -it ubuntu:22.04 /bin/bash `

Execute commands in running container:

`bash docker exec -it webserver /bin/bash `

Container Logs and Monitoring

View container logs:

`bash docker logs webserver docker logs -f webserver # Follow logs in real-time `

Monitor container resource usage:

`bash docker stats webserver `

Docker Compose for Multi-Container Applications

Docker Compose simplifies managing multi-container applications using YAML configuration files.

Installing Docker Compose

Docker Compose is now included as a plugin with Docker Engine. Verify installation:

`bash docker compose version `

Creating a Docker Compose File

Create docker-compose.yml:

`yaml version: '3.8'

services: web: build: . ports: - "8000:8000" volumes: - .:/app environment: - DEBUG=1 depends_on: - db - redis

db: image: postgres:15 environment: POSTGRES_DB: myapp POSTGRES_USER: user POSTGRES_PASSWORD: password volumes: - postgres_data:/var/lib/postgresql/data ports: - "5432:5432"

redis: image: redis:7-alpine ports: - "6379:6379"

volumes: postgres_data: `

Docker Compose Commands

Start services:

`bash docker compose up -d `

View running services:

`bash docker compose ps `

Stop services:

`bash docker compose down `

View logs:

`bash docker compose logs web `

Scale services:

`bash docker compose up --scale web=3 `

Advanced Docker Usage

Docker Networking

Create a custom network:

`bash docker network create mynetwork `

Run containers on custom network:

`bash docker run -d --name app1 --network mynetwork nginx docker run -d --name app2 --network mynetwork nginx `

Volume Management

Create a named volume:

`bash docker volume create mydata `

Use volume in container:

`bash docker run -d -v mydata:/data nginx `

Bind mount host directory:

`bash docker run -d -v /host/path:/container/path nginx `

Environment Variables and Secrets

Pass environment variables:

`bash docker run -e ENV_VAR=value -e DB_PASSWORD=secret nginx `

Use environment file:

`bash docker run --env-file .env nginx `

Best Practices for Docker on Linux

Security Best Practices

1. Use official base images: Start with official, minimal base images 2. Run as non-root user: Create and use non-root users in containers 3. Keep images updated: Regularly update base images and dependencies 4. Scan for vulnerabilities: Use tools like Docker Scout or Trivy 5. Limit container privileges: Use --user flag and avoid --privileged

Performance Optimization

1. Multi-stage builds: Reduce image size with multi-stage Dockerfiles 2. Layer caching: Optimize Dockerfile layer ordering 3. Resource limits: Set memory and CPU limits for containers 4. Use .dockerignore: Exclude unnecessary files from build context

Example optimized Dockerfile:

`dockerfile

Multi-stage build

FROM node:18-alpine AS runtime RUN addgroup -g 1001 -S nodejs && \ adduser -S nextjs -u 1001 WORKDIR /app COPY --from=builder --chown=nextjs:nodejs /app/node_modules ./node_modules COPY --chown=nextjs:nodejs . . USER nextjs EXPOSE 3000 CMD ["npm", "start"] `

Troubleshooting Common Issues

Docker Daemon Issues

If Docker daemon isn't running:

`bash sudo systemctl status docker sudo systemctl restart docker `

Permission Denied Errors

Ensure user is in docker group:

`bash groups $USER sudo usermod -aG docker $USER `

Storage Issues

Clean up unused resources:

`bash docker system prune -a docker volume prune `

Frequently Asked Questions (FAQ)

Q: What's the difference between Docker containers and virtual machines? A: Containers share the host OS kernel and are more lightweight, while VMs include a full OS. Containers start faster and use fewer resources.

Q: Can I run Docker on older Linux distributions? A: Docker requires kernel version 3.10 or higher. Older distributions may need kernel updates or use older Docker versions.

Q: How do I persist data in Docker containers? A: Use Docker volumes or bind mounts to persist data outside the container filesystem.

Q: Is Docker free for commercial use in 2025? A: Docker Engine remains free and open-source. Docker Desktop has licensing restrictions for large organizations.

Q: How do I update Docker on Linux? A: Use your distribution's package manager: sudo apt update && sudo apt upgrade docker-ce for Ubuntu/Debian.

Q: Can I run GUI applications in Docker containers? A: Yes, but it requires additional configuration for X11 forwarding or using tools like VNC.

Conclusion

Docker on Linux provides a powerful platform for containerization and modern DevOps practices. This tutorial covered everything from basic installation to advanced usage with Docker Compose, giving you the foundation needed to leverage containerization effectively in 2025.

As containerization continues to evolve, Docker remains an essential tool for developers and DevOps professionals. The combination of Docker's flexibility with Linux's stability creates an ideal environment for deploying scalable, efficient applications.

Start with simple containers and gradually explore advanced features like orchestration, networking, and security. With practice, you'll master Docker and unlock the full potential of containerization for your projects and infrastructure.

Remember to stay updated with Docker's latest features and security practices as the technology continues to advance throughout 2025 and beyond.