Docker Docker Installation and Basics Installing Docker on Linux Windows Mac

1. Core Command / Concept

Install Docker on Linux, Windows, and Mac using official installation scripts. curl -sSL https://get.docker.com/ | sh

2. Step-by-Step (numbered)

1. Check if your system meets the Docker installation requirements: uname -a
2. Install Docker on Linux (Ubuntu/Debian): sudo apt-get update && sudo apt-get install -y docker.io
3. Install Docker on Linux (RHEL/CentOS): sudo yum install -y docker
4. Install Docker on Windows (using WSL): wsl --install -d docker-desktop
5. Install Docker on Mac (using Homebrew): brew install --cask docker
6. Start the Docker service: sudo systemctl start docker
7. Enable Docker to start at boot: sudo systemctl enable docker
8. Verify Docker installation: docker --version
9. Clean up: sudo apt-get autoremove ⚠️ This deletes all stopped containers: docker rm $(docker ps -aq)

3. Real Commands with Examples

Example 1: Install Docker on Linux (Ubuntu/Debian)

• Purpose: Install Docker on Ubuntu/Debian.
• Command: sudo apt-get update && sudo apt-get install -y docker.io
• Brief explanation of flags: -y automatically answers yes to all prompts.

Example 2: Install Docker on Windows (using WSL)

• Purpose: Install Docker on Windows using WSL.
• Command: wsl --install -d docker-desktop
• Brief explanation of flags: -d specifies the distribution to install.

Example 3: Install Docker on Mac (using Homebrew)

• Purpose: Install Docker on Mac using Homebrew.
• Command: brew install --cask docker
• Brief explanation of flags: --cask installs a Cask package.

4. Common Errors (3-5)

Error 1: Unable to install Docker due to missing dependencies.

• Error message or symptom: E: Unable to locate package docker.io
• Why it happens: The system is missing required dependencies.
• One-line fix: sudo apt-get update && sudo apt-get install -y apt-transport-https ca-certificates curl software-properties-common

Error 2: Docker installation fails due to conflicting packages.

• Error message or symptom: Error: Package 'docker' is not installed, but is referred to by another package.
• Why it happens: Another package is trying to install Docker.
• One-line fix: sudo apt-get install -y docker.io

Error 3: Docker service fails to start.

• Error message or symptom: Job for docker.service failed because the control process exited with error code.
• Why it happens: The Docker service is not configured correctly.
• One-line fix: sudo systemctl restart docker

5. Quick Checks (3 scenarios)

Scenario 1: Check if Docker is installed.

• Situation: You want to verify if Docker is installed.
• Command to run: docker --version
• What a correct response looks like: Docker version 20.10.7, build 20.10.7-0ubuntu5~20.04.2

Scenario 2: Check if Docker is running.

• Situation: You want to verify if Docker is running.
• Command to run: sudo systemctl status docker
• What a correct response looks like: Active: active (running)

Scenario 3: Check Docker version.

• Situation: You want to verify the Docker version.
• Command to run: docker version
• What a correct response looks like: Client: Docker Engine - Community
  Server: Docker Engine - Community

6. Last-Minute Reference

• Docker installation script: https://get.docker.com/
• Docker installation package: docker.io
• Docker service name: docker
• Docker version command: docker --version
• Docker version output format: Client: Docker Engine - Community Server: Docker Engine - Community
• ⚠️ Docker installation requires root privileges.
• ⚠️ Docker installation may require additional dependencies.
• ⚠️ Docker service may require manual configuration.