How to run first Docker container

Introduction

Docker is a powerful platform that revolutionizes software development and deployment through containerization technology. This tutorial provides a comprehensive guide for developers and IT professionals to understand the fundamentals of Docker and successfully run their first container, enabling efficient and consistent application environments across different systems.

Skills Graph

%%%%{init: {'theme':'neutral'}}%%%% flowchart RL docker(("`Docker`")) -.-> docker/ContainerOperationsGroup(["`Container Operations`"]) docker(("`Docker`")) -.-> docker/ImageOperationsGroup(["`Image Operations`"]) docker(("`Docker`")) -.-> docker/SystemManagementGroup(["`System Management`"]) docker/ContainerOperationsGroup -.-> docker/create("`Create Container`") docker/ContainerOperationsGroup -.-> docker/rm("`Remove Container`") docker/ContainerOperationsGroup -.-> docker/ps("`List Running Containers`") docker/ContainerOperationsGroup -.-> docker/run("`Run a Container`") docker/ContainerOperationsGroup -.-> docker/stop("`Stop Container`") docker/ImageOperationsGroup -.-> docker/pull("`Pull Image from Repository`") docker/ImageOperationsGroup -.-> docker/images("`List Images`") docker/SystemManagementGroup -.-> docker/info("`Display System-Wide Information`") docker/SystemManagementGroup -.-> docker/version("`Show Docker Version`") subgraph Lab Skills docker/create -.-> lab-418476{{"`How to run first Docker container`"}} docker/rm -.-> lab-418476{{"`How to run first Docker container`"}} docker/ps -.-> lab-418476{{"`How to run first Docker container`"}} docker/run -.-> lab-418476{{"`How to run first Docker container`"}} docker/stop -.-> lab-418476{{"`How to run first Docker container`"}} docker/pull -.-> lab-418476{{"`How to run first Docker container`"}} docker/images -.-> lab-418476{{"`How to run first Docker container`"}} docker/info -.-> lab-418476{{"`How to run first Docker container`"}} docker/version -.-> lab-418476{{"`How to run first Docker container`"}} end

Docker Fundamentals

What is Docker?

Docker is an open-source platform that enables developers to automate application deployment, scaling, and management through containerization. It provides a lightweight, portable, and self-sufficient environment for running applications.

Core Concepts

Containers

Containers are lightweight, standalone, executable packages that include everything needed to run an application: code, runtime, system tools, libraries, and settings.

graph LR A[Application Code] --> B[Container] C[Dependencies] --> B D[Runtime Environment] --> B

Docker Images

Docker images are read-only templates used to create containers. They serve as the basis for container creation and can be stored in registries like Docker Hub.

Docker Architecture

Component	Description
Docker Client	Command-line interface for interacting with Docker
Docker Daemon	Background service managing Docker objects
Docker Registry	Storage and distribution system for Docker images

Key Advantages

Consistency: Ensures identical environments across development and production
Isolation: Separates applications and their dependencies
Efficiency: Lightweight compared to traditional virtual machines
Scalability: Easy to scale applications horizontally

Use Cases

Microservices deployment
Continuous Integration/Continuous Deployment (CI/CD)
Cloud-native application development
Development and testing environments

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Docker vs Traditional Virtualization

graph TD A[Traditional Virtualization] --> B[Full OS for each application] A --> C[High Resource Overhead] D[Docker Containerization] --> E[Shared OS Kernel] D --> F[Lightweight Containers]

By understanding these fundamentals, you'll be well-prepared to dive into Docker and leverage its powerful containerization capabilities.

Setup and Config

System Requirements

Before installing Docker, ensure your Ubuntu 22.04 system meets the following requirements:

64-bit operating system
Linux kernel 3.10 or higher
Minimum 2GB RAM
Sufficient disk space

Installation Methods

Method 1: Official Docker Repository

## Update package index
sudo apt-get update

## Install required packages
sudo apt-get install ca-certificates curl gnupg lsb-release

## 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

## Set up stable repository
echo \
  "deb [arch=$(dpkg --print-architecture) 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-get update
sudo apt-get install docker-ce docker-ce-cli containerd.io

Method 2: Convenience Script

## Download and run Docker installation script
curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh

Post-Installation Configuration

User Group Configuration

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

## Verify installation
docker --version

Docker Configuration Files

File Path	Purpose
`/etc/docker/daemon.json`	Docker daemon configuration
`~/.docker/config.json`	User-specific Docker settings

Docker Compose Installation

## Download Docker Compose
sudo curl -L "https://github.com/docker/compose/releases/latest/download/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

## Apply executable permissions
sudo chmod +x /usr/local/bin/docker-compose

## Verify installation
docker-compose --version

Verification Workflow

graph TD A[Install Docker] --> B[Add User to Docker Group] B --> C[Verify Docker Version] C --> D[Run Test Container] D --> E[Confirm Successful Setup]

Testing Docker Installation

## Run hello-world container
sudo docker run hello-world

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Common Troubleshooting

Restart Docker service: sudo systemctl restart docker
Check Docker status: sudo systemctl status docker
Verify network connectivity: docker info

Running First Container

Basic Docker Commands

Pulling an Image

## Pull Ubuntu image from Docker Hub
docker pull ubuntu:latest

Container Lifecycle Commands

Command	Description
`docker run`	Create and start a new container
`docker ps`	List running containers
`docker ps -a`	List all containers
`docker start`	Start a stopped container
`docker stop`	Stop a running container

Interactive Container Execution

## Run Ubuntu container interactively
docker run -it ubuntu:latest /bin/bash

Container Modes

graph LR A[Container Modes] --> B[Interactive Mode] A --> C[Detached Mode] A --> D[Foreground Mode] A --> E[Background Mode]

Detached Mode Example

## Run Nginx web server in background
docker run -d -p 80:80 nginx:latest

Port Mapping

## Map container port to host port
docker run -d -p 8080:80 nginx:latest

Volume Mounting

## Mount host directory to container
docker run -v /host/path:/container/path ubuntu:latest

Environment Variables

## Set environment variables
docker run -e MYSQL_ROOT_PASSWORD=secret mysql:latest

Container Management

## Remove a container
docker rm container_name

## Remove all stopped containers
docker container prune

Advanced Container Operations

Inspecting Containers

## View container details
docker inspect container_name

## Check container logs
docker logs container_name

Best Practices

Use official images
Keep containers lightweight
Use specific image tags
Implement proper resource limits

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Container Workflow

graph TD A[Pull Image] --> B[Create Container] B --> C[Start Container] C --> D[Interact/Use Container] D --> E[Stop Container] E --> F[Remove Container]

Common Scenarios

Scenario	Docker Command
Web Server	`docker run -d -p 80:80 nginx`
Database	`docker run -d mysql:latest`
Python App	`docker run -it python:3.9`

Troubleshooting Tips

Check container status: docker ps
View container logs: docker logs
Restart container: docker restart

Summary

By following this tutorial, you have learned the essential steps to set up Docker, configure your environment, and run your first container. Docker offers a robust solution for application packaging, distribution, and deployment, allowing developers to create portable and scalable software solutions with minimal configuration and maximum consistency across different computing environments.