🐳 Docker Installation — Complete Setup Guide

🧠 What is Docker?

Docker is a platform used to build, run, and manage containerized applications. It packages code, dependencies, and environment configurations into a single container image, ensuring consistent behavior across systems.

⚙️ Step 1: Install Docker on Ubuntu (Linux)

🧩 1. Update and Install Required Packages

sudo apt update
sudo apt install ca-certificates curl gnupg lsb-release -y

🧩 2. 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

🧩 3. Set Up the Docker 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

🧩 4. Install Docker Engine, CLI, and Compose

sudo apt update
sudo apt install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin -y

🧩 5. Verify Docker Installation

sudo systemctl start docker
sudo systemctl enable docker
docker --version

✅ Output example:

Docker version 27.0.0, build xxxxxxx

🧩 6. Run Docker Without sudo

By default, Docker requires sudo. To fix this, add your user to the Docker group:

sudo usermod -aG docker $USER && newgrp docker

Then verify:

docker run hello-world

✅ If it prints “Hello from Docker!”, your setup works perfectly.

🪟 Step 2: Install Docker on Windows

🧩 1. Download Docker Desktop

Go to: 👉 https://www.docker.com/products/docker-desktop

🧩 2. Install

• Run the installer (Docker Desktop Installer.exe)
• Enable WSL 2 and Hyper-V when prompted
• Complete installation and reboot if required

🧩 3. Verify

Open PowerShell or CMD:

docker --version

Run test container:

docker run hello-world

✅ You should see the Docker welcome message.

🍏 Step 3: Install Docker on macOS

🧩 1. Download Docker Desktop

Go to: 👉 https://www.docker.com/products/docker-desktop

🧩 2. Install

• Download .dmg file
• Drag Docker.app to Applications
• Launch Docker Desktop from Launchpad

🧩 3. Verify

Open Terminal:

docker --version
docker run hello-world

✅ Output: Docker runs successfully on macOS.

🧰 Step 4: Common Post-Installation Commands

docker ps              # list running containers
docker images          # list images
docker stop <id>       # stop container
docker rm <id>         # remove container
docker rmi <id>        # remove image
docker system prune -a # clean up everything