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Docker Installation - Getting Started with Containers

Status: Active
Last Updated: 2026-01-30
Category: Containers - Setup
Prerequisites: docker-concepts, kb/basics/linux-fundamentals
Time: 1-2 hours
Tags: docker, podman, installation, setup, linux, macos, windows

Summary

Install Docker and Podman on Linux, macOS, and Windows. Complete setup including post-installation configuration, verification, and troubleshooting. Choose between Docker Desktop, Docker Engine, or Podman based on your needs.

🎯 What You'll Learn

By the end of this article, you'll be able to:

🤔 Choosing Your Path

Docker vs Podman Decision

Quick Recommendation:

🐧 Linux Installation

Option 1: Docker Engine (Most Popular)

Supports: Ubuntu, Debian, Fedora, RHEL, CentOS, Arch

Ubuntu/Debian Installation

# 1. Remove old versions (if any)
sudo apt remove docker docker-engine docker.io containerd runc

# 2. Update package index
sudo apt update

# 3. Install prerequisites
sudo apt install -y \
    apt-transport-https \
    ca-certificates \
    curl \
    gnupg \
    lsb-release

# 4. Add Docker's official GPG key
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | \
    sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg

# 5. Set up repository
echo \
  "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] \
  https://download.docker.com/linux/ubuntu \
  $(lsb_release -cs) stable" | \
  sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

# 6. Install Docker Engine
sudo apt update
sudo apt install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

# 7. Verify installation
sudo docker run hello-world

For Debian: Replace ubuntu with debian in step 5.

Fedora/RHEL/CentOS Installation

# 1. Remove old versions
sudo dnf remove docker docker-client docker-client-latest docker-common \
    docker-latest docker-latest-logrotate docker-logrotate docker-engine

# 2. Install dependencies
sudo dnf -y install dnf-plugins-core

# 3. Add repository
sudo dnf config-manager --add-repo \
    https://download.docker.com/linux/fedora/docker-ce.repo

# 4. Install Docker Engine
sudo dnf install -y docker-ce docker-ce-cli containerd.io \
    docker-buildx-plugin docker-compose-plugin

# 5. Start Docker service
sudo systemctl start docker
sudo systemctl enable docker

# 6. Verify
sudo docker run hello-world

Arch Linux Installation

# Install from official repos
sudo pacman -S docker docker-compose

# Start and enable service
sudo systemctl start docker.service
sudo systemctl enable docker.service

# Verify
sudo docker run hello-world

Option 2: Podman (Rootless Alternative)

Why Podman?

Podman on Ubuntu/Debian

# Ubuntu 20.10+
sudo apt update
sudo apt install -y podman

# Verify
podman --version
podman run hello-world

Podman on Fedora/RHEL

# Pre-installed on Fedora 32+
# Or install:
sudo dnf install -y podman podman-compose

# Verify
podman --version
podman run hello-world

Podman on Arch

sudo pacman -S podman podman-compose

# Verify
podman --version

Post-Installation: Run Docker Without Sudo

Problem: docker commands require sudo by default.

Solution: Add your user to docker group.

# Create docker group (usually exists)
sudo groupadd docker

# Add your user to docker group
sudo usermod -aG docker $USER

# Apply group changes (log out/in or run)
newgrp docker

# Verify non-root access
docker run hello-world

# If still fails, check Docker socket permissions
sudo chmod 666 /var/run/docker.sock  # Quick fix
# Or properly:
sudo chown root:docker /var/run/docker.sock

Security Note: Users in docker group have root-equivalent privileges. Be cautious in multi-user systems.

Docker as Systemd Service

# Enable Docker to start on boot
sudo systemctl enable docker

# Start Docker service
sudo systemctl start docker

# Check status
sudo systemctl status docker

# View logs
sudo journalctl -u docker.service -f

🪟 Windows Installation

Docker Desktop for Windows

Requirements:

Installation Steps

  1. Download Docker Desktop:

  2. Run Installer:

    • Double-click Docker Desktop Installer.exe
    • Follow wizard (enable WSL 2 option)

  3. Enable WSL 2 (if not already):

    # Run PowerShell as Administrator
wsl --install
wsl --set-default-version 2

  4. Start Docker Desktop:

    • Launch from Start menu
    • Wait for Docker engine to start (whale icon in system tray)

  5. Verify Installation:

    # In PowerShell or CMD
docker --version
docker run hello-world

Docker Desktop Settings

Recommended Configurations:

Alternative: Podman on Windows

Podman Desktop (newer, experimental):

  1. Download: podman-desktop.io
  2. Install: Run installer
  3. Verify:
    podman --version
podman run hello-world

Note: Podman on Windows uses a Linux VM internally (like Docker Desktop).

🍎 macOS Installation

Docker Desktop for macOS

Requirements:

Installation Steps

  1. Download Docker Desktop:

  2. Install:

    • Open .dmg file
    • Drag Docker to Applications folder
    • Launch Docker from Applications

  3. Grant Permissions:

    • First run asks for privileged access (approve)
    • Required for network and filesystem access

  4. Verify:

    docker --version
docker run hello-world

Docker Desktop Settings (macOS)

Resources:

Alternative: Podman on macOS

Using Homebrew:

# Install Podman
brew install podman

# Initialize Podman machine (Linux VM)
podman machine init

# Start Podman machine
podman machine start

# Verify
podman --version
podman run hello-world

# Alias docker → podman (optional)
echo 'alias docker=podman' >> ~/.zshrc
source ~/.zshrc

✅ Verification and Testing

Basic Verification

# Check Docker version
docker --version
# Should show: Docker version 25.0.x, build xxxxx

# Check Docker info
docker info
# Shows: containers, images, storage driver, etc.

# Run test container
docker run hello-world
# Should pull image and show success message

# Check running containers
docker ps

# Check all containers (including stopped)
docker ps -a

# List downloaded images
docker images

Test Real Container

# Run Nginx web server
docker run -d -p 8080:80 --name test-nginx nginx:latest

# Verify it's running
docker ps

# Test web server
curl http://localhost:8080
# Should show "Welcome to nginx!"

# Or open browser: http://localhost:8080

# View logs
docker logs test-nginx

# Stop and remove
docker stop test-nginx
docker rm test-nginx

Podman Verification

# Same commands work!
podman --version
podman info
podman run hello-world
podman ps
podman images

# Test Nginx
podman run -d -p 8080:80 --name test-nginx nginx:latest
curl http://localhost:8080

# Cleanup
podman stop test-nginx
podman rm test-nginx

🔧 Configuration

Docker Configuration File

Location: /etc/docker/daemon.json (Linux) or Docker Desktop settings (Win/Mac)

Example Configuration:

{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "10m",
    "max-file": "3"
  },
  "storage-driver": "overlay2",
  "default-address-pools": [
    {
      "base": "172.17.0.0/12",
      "size": 24
    }
  ],
  "dns": ["8.8.8.8", "8.8.4.4"],
  "insecure-registries": [],
  "registry-mirrors": []
}

Apply Changes:

# Linux
sudo systemctl restart docker

# Or Docker Desktop: Restart from GUI

Useful Docker Settings

Log Rotation (prevent huge logs):

{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "10m",
    "max-file": "3"
  }
}

Storage Driver (Linux):

{
  "storage-driver": "overlay2"
}

Custom DNS:

{
  "dns": ["1.1.1.1", "8.8.8.8"]
}

Podman Configuration

Location: ~/.config/containers/containers.conf (rootless) or /etc/containers/containers.conf (root)

Example Configuration:

[engine]
# Number of parallel image pulls
image_parallel_copies = 3

[containers]
# Default network mode
netns = "bridge"

# Log driver
log_driver = "journald"

🚨 Troubleshooting

Issue 1: "Permission Denied" on Linux

Symptom:

Got permission denied while trying to connect to the Docker daemon socket

Solution:

# Add user to docker group
sudo usermod -aG docker $USER

# Log out and log back in, or:
newgrp docker

# Verify
docker run hello-world

Issue 2: Docker Service Not Running

Symptom:

Cannot connect to the Docker daemon at unix:///var/run/docker.sock

Solution:

# Check service status
sudo systemctl status docker

# Start if stopped
sudo systemctl start docker

# Enable on boot
sudo systemctl enable docker

# Check for errors
sudo journalctl -u docker.service -n 50

Issue 3: WSL 2 Not Installed (Windows)

Symptom: Docker Desktop fails to start, mentions WSL 2

Solution:

# Run as Administrator in PowerShell
wsl --install
wsl --set-default-version 2

# Restart computer
# Then start Docker Desktop

Issue 4: VT-x/AMD-V Not Enabled

Symptom: Virtualization error on Windows/Mac

Solution:

  1. Enter BIOS/UEFI settings (reboot, press F2/Del/F12)
  2. Find "Virtualization Technology" or "VT-x" or "AMD-V"
  3. Enable it
  4. Save and exit
  5. Restart Docker Desktop

Issue 5: Podman Cannot Pull Images

Symptom: Error: short-name "nginx" did not resolve to an alias

Solution:

# Specify full registry
podman run docker.io/nginx:latest

# Or configure default registry
echo 'unqualified-search-registries=["docker.io"]' | \
    sudo tee -a /etc/containers/registries.conf

# Restart Podman machine (macOS)
podman machine stop
podman machine start

Issue 6: Storage Space Issues

Check Docker Disk Usage:

docker system df

Clean Up:

# Remove unused data
docker system prune

# Remove everything (be careful!)
docker system prune -a --volumes

🔒 Security Considerations

Docker Socket Permissions

Understand the Risk: Access to Docker socket = root access!

Best Practices:

  1. Don't expose Docker socket over network
  2. Limit who is in docker group
  3. Consider rootless Docker (experimental)
  4. Use Podman for rootless by default

Rootless Docker (Advanced)

Install Rootless Docker:

# Install rootless Docker
curl -fsSL https://get.docker.com/rootless | sh

# Add to PATH
export PATH=/home/$USER/bin:$PATH
export DOCKER_HOST=unix:///run/user/$(id -u)/docker.sock

# Add to .bashrc or .zshrc
echo 'export PATH=/home/$USER/bin:$PATH' >> ~/.bashrc
echo 'export DOCKER_HOST=unix:///run/user/$(id -u)/docker.sock' >> ~/.bashrc

Limitations:

💡 Quick Tips

Alias for Podman Users:

# Make podman respond to docker commands
echo 'alias docker=podman' >> ~/.bashrc
source ~/.bashrc

Docker Compose Alias (older systems):

# If docker-compose not installed
alias docker-compose='docker compose'

Check What's Using Disk:

docker system df -v

Fast Cleanup:

# Remove stopped containers
docker container prune

# Remove unused images
docker image prune

# Remove unused volumes
docker volume prune

🔗 What's Next?

Installation complete! Now learn to use Docker:

Hands-On:

Building Images:

Storage:

📚 Resources

Official Docs:

Troubleshooting:

📝 Change Log

2026-01-30

Next Article: docker-basics - Learn essential Docker commands!

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