Introduction to Docker
Docker has revolutionized the way we develop, ship, and run applications. It’s a powerful platform that simplifies application deployment, enabling you to package your software and all its dependencies into a single, portable unit called a container. This approach allows for consistency across different environments, faster development cycles, and efficient resource utilization. In this article, we’ll provide an introduction to Docker and guide you through the installation process on an Ubuntu system.
What is Docker?
Docker is an open-source containerization platform that enables you to isolate applications and their dependencies, ensuring they run consistently across various environments. Containers are lightweight, standalone units that package everything an application needs, including the code, runtime, system tools, libraries, and settings. This containerization approach offers several advantages:
- Consistency: Containers ensure that your application runs the same way in development, testing, and production environments.
- Portability: You can move containers between different host systems and cloud platforms, making it easier to scale and migrate applications.
- Resource Efficiency: Containers share the host OS kernel, resulting in minimal overhead and efficient resource utilization.
- Fast Deployment: Containers can start and stop quickly, reducing deployment times and enabling continuous integration and continuous deployment (CI/CD) pipelines.
Installation of Docker in Ubuntu
Installing Docker on an Ubuntu system is a straightforward process. Here’s a step-by-step guide to get you started:
Step 1: Update Package Lists
Before you begin, it’s a good practice to ensure that your package list is up to date. Open a terminal and run the following command:
sudo apt update
Step 2: Install Dependencies
You will need a few packages to enable the installation process. Install them by running:
sudo apt install -y apt-transport-https ca-certificates curl software-properties-common
Step 3: Add Docker Repository
Add Docker’s official GPG key and repository to your system. This step ensures you’ll be downloading Docker from a trusted source:
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg –dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
Then add the Docker repository:
echo “deb [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
Step 4: Install Docker
Now that you’ve added the Docker repository, you can install Docker with the following command:
sudo apt update
sudo apt install -y docker-ce docker-ce-cli containerd.io
Step 5: Start and Enable Docker
Once the installation is complete, start the Docker service and enable it to start at boot
sudo systemctl start docker
sudo systemctl enable docker
Step 6: Verify Installation
To ensure that Docker is installed and working correctly, run the following command to check the Docker version:
You should see the Docker version displayed, indicating a successful installation.
Docker is a powerful tool that simplifies the deployment and management of applications. With Docker, you can create consistent, portable, and efficient containers that make it easier to develop and run your software. By following this guide, you’ve successfully installed Docker on your Ubuntu system, setting the stage for you to explore the world of containerization and streamline your application deployment processes.
What is Docker and Why is it Used?
Docker is a containerization platform that allows you to package and distribute applications and their dependencies in a consistent and portable manner. It creates lightweight, isolated containers that can run applications consistently across various environments.. Docker simplifies application deployment, scalability, and management, making it easier to develop, ship, and run software.
Is Docker a Virtual Machine?
No, Docker is not a virtual machine. Docker containers lack the full-fledged virtualization capabilities found in virtual machines (VMs). Instead, containers share the host operating system’s kernel and run in isolated user spaces. This makes containers more lightweight, efficient, and faster to start compared to VMs.
What is Docker in DevOps?
In DevOps, Docker plays a crucial role in enabling consistent and reliable application deployment and orchestration. Docker containers are often used to package and deploy applications, making it easier to automate deployment processes. They also facilitate the scaling of applications and services in a microservices architecture. Docker images can be version-controlled, and with tools like Docker Compose and Kubernetes, DevOps teams can manage containerized applications efficiently.
Is Docker Free for Linux?
Docker offers both a free and open-source edition called Docker Community Edition (CE) and a paid version called Docker Enterprise Edition (EE). Its CE version is free to use, including on Linux. Docker EE, on the other hand, is a commercial product with additional features and support options. Linux users can enjoy the benefits of Docker containerization without incurring licensing costs by using Docker CE.