Docker Guide: Install, Configure, and Use Basics

Introduction

Docker is a powerful platform for developing, shipping, and running applications in lightweight, portable containers. Unlike traditional virtual machines, Docker containers share the host OS kernel, making them faster and more efficient.

In this blog, we'll cover:

Docker Installation
Basic Configuration
Fundamental Docker Commands

1. Docker Installation

On Linux (Ubuntu/Debian)

Update your system:

 sudo apt update && sudo apt upgrade -y

Install required packages:

 sudo apt install apt-transport-https ca-certificates curl software-properties-common -y

Add Docker’s official GPG key:

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

Add Docker repository:

 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:

 sudo apt update && sudo apt install docker-ce docker-ce-cli containerd.io -y

Verify installation:
```
 sudo docker run hello-world
```

On Windows/macOS

Download Docker Desktop from the official website:
- https://www.docker.com/products/docker-desktop
Follow the installation wizard.
After installation, open a terminal and verify:
```
  docker --version
```

2. Docker Configuration

Managing Docker as a Non-Root User (Linux)

By default, Docker requires sudo. To avoid this:

sudo usermod -aG docker $USER  
newgrp docker

Now, you can run Docker commands without sudo.

Starting & Enabling Docker Service (Linux)

sudo systemctl start docker  
sudo systemctl enable docker

Configuring Docker to Start on Boot (Windows/macOS)

Open Docker Desktop → Settings → General → Enable "Start Docker Desktop when you log in".

3. Basic Docker Usage

Working with Docker Images

Pull an image from Docker Hub:
```
  docker pull ubuntu:latest
```
List downloaded images:
```
  docker images
```
Remove an image:
```
  docker rmi ubuntu:latest
```

Running Containers

Run a container in interactive mode:
```
  docker run -it ubuntu /bin/bash
```
Run a container in detached mode (background):
```
  docker run -d --name my_container nginx
```
List running containers:
```
  docker ps
```
List all containers (including stopped ones):
```
  docker ps -a
```
Stop a container:
```
  docker stop my_container
```
Start a stopped container:
```
  docker start my_container
```
Remove a container:
```
  docker rm my_container
```

Managing Ports & Volumes

Expose a container port to the host:

  docker run -d -p 8080:80 --name nginx_server nginx

Mount a host directory as a volume:

  docker run -v /host/path:/container/path ubuntu

Docker Logs & Exec

View container logs:
```
  docker logs my_container
```

Execute a command inside a running container:

  docker exec -it my_container /bin/bash

Conclusion

Docker simplifies application deployment by encapsulating environments into containers. We covered:
✅ Installation on Linux, Windows, and macOS
✅ Basic configuration (non-root access, auto-start)
✅ Essential commands for managing images & containers

Next steps? Try building your own Docker images using Dockerfile and explore Docker Compose for multi-container setups!

Happy Dockering! 🐳

Docker Fundamentals: Installation, Configuration, and Basic Usage