Docker Tutorial 2: What is Docker?

Introduction

This tutorial will guide you through the basics of Docker, a powerful platform for developing, shipping, and running applications in containers. Understanding Docker is essential for modern software development, as it helps create consistent environments across various systems. This guide will help you set up Docker on your machine, regardless of whether you're using Windows, Mac, or Linux.

Step 1: Understand What Docker Is

Docker is a containerization platform that allows developers to package applications and their dependencies into containers. Key benefits include:

• Environment Consistency: Containers run the same way regardless of where they are deployed.
• Isolation: Each container operates independently, reducing conflicts between applications.
• Efficiency: Containers share the host OS kernel, making them lightweight compared to virtual machines.

Practical Tip

Familiarize yourself with basic Docker terminology such as containers, images, Docker Hub, and Dockerfile. This foundational knowledge will help you understand how to work with Docker effectively.

Step 2: Install Docker on Your Machine

The installation process varies based on your operating system.

For Windows and Mac

1. Visit the Docker Hub website: Docker for Windows/Mac.
2. Download the Docker Desktop application.
3. Follow the installation instructions provided on the website.
4. Once installed, open Docker Desktop and ensure it's running.

For Ubuntu

1. Follow the tutorial on DigitalOcean: Install Docker on Ubuntu 18.04.
2. Update your package index:

   sudo apt-get update
   

3. Install required packages:

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

4. Add the Docker GPG key:

   curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
   

5. Add Docker's official repository:

   sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
   

6. Install Docker:

   sudo apt-get update
   sudo apt-get install docker-ce
   

For CentOS

1. Refer to the DigitalOcean tutorial: Install Docker on CentOS 7.
2. Update your system:

   sudo yum update
   

3. Install required packages:

   sudo yum install -y yum-utils device-mapper-persistent-data lvm2
   

4. Set up the stable repository:

   sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
   

5. Install Docker:

   sudo yum install docker-ce
   

6. Start the Docker service:

   sudo systemctl start docker
   

Step 3: Verify Docker Installation

1. Open your terminal or command prompt.
2. Run the following command to check the Docker version:

   docker --version
   

3. To test Docker, run:

   sudo docker run hello-world
   

   This command pulls the "hello-world" image and runs it in a container, confirming that Docker is functioning correctly.

Conclusion

You have successfully installed Docker on your machine and learned about its core concepts. Docker streamlines the development process by allowing applications to run consistently across different environments. As a next step, consider exploring Docker Hub for pre-built images, or dive deeper into creating your own Dockerfiles to customize your containers. Happy coding!