Docker on Ubuntu

 

Docker on Ubuntu: Understanding Installation and Architecture

Container technology plays an important role in software development and server operations.

Among container platforms, Docker is one of the most widely used tools, allowing applications to run in consistent and executable environments.

Ubuntu is one of the Linux distributions well suited for using Docker.

Thanks to its stable package management system, abundant resources and documentation, and active user community, it is widely used by everyone from beginners to experts.

1. The Relationship Between Docker and Ubuntu

Docker is a technology built on core Linux kernel features.

Ubuntu reliably supports these kernel capabilities and is frequently referenced in official Docker documentation as a recommended environment.

Key advantages of using Docker on Ubuntu include:

• Clear package management based on APT

• Availability of Long-Term Support (LTS) releases

• High compatibility with Docker’s official repositories

• Usability in both server and desktop environments

For these reasons, Ubuntu is often considered an excellent platform for learning and experimenting with Docker.

2. Basic Concepts Before Installing Docker

Understanding a few basic concepts before installation makes the process easier to follow.

What Does Installing Docker Include?

Installing Docker is not just about adding a single application. It typically includes:

• Docker Engine (the core runtime component)

• Docker CLI (the command-line interface)

• A background service for managing containers

In this sense, Docker can be viewed as a combination of services, tools, and a runtime environment.

3. Overview of Docker Installation on Ubuntu

There are multiple ways to install Docker on Ubuntu, but the commonly used process follows this general flow:

• Update system package lists

• Prepare prerequisite packages

• Add Docker’s official repository

• Install Docker Engine

• Verify Docker service status

Most of these steps are performed in the terminal.

Once installation is complete, Docker commands can be used to run containers.

This article focuses on understanding the structure rather than listing specific commands.

4. Understanding the Docker Engine Architecture

The Docker Engine is the core component of Docker.

After installation on Ubuntu, it runs as a system service.

Docker Engine consists of three main components:

4.1 Docker Daemon

• A background service that performs core operations

• Responsible for creating, running, stopping, and removing containers

• Handles image management and network configuration

When users enter Docker commands, the Docker Daemon performs the actual work.

4.2 Docker CLI

• The command-line tool used by users

• Provides commands such as docker run and docker ps

• Sends requests to the Docker Daemon

The CLI itself is lightweight; most logic is handled by the daemon.

4.3 REST API

• Communication channel between the CLI and the Docker Daemon

• Enables integration with automation tools and external systems

• One reason Docker can be used in diverse environments

5. Docker Image Structure

One of Docker’s core concepts is the image.

A Docker image serves as a blueprint for running applications.

Key characteristics of Docker images:

• Read-only by design

• Composed of multiple layers

• Reusable across environments

• Version-controlled

Each layer stores only the changes it introduces, making storage and network usage more efficient.

6. Docker Container Structure

A container is a running instance created from an image.

Multiple containers can be created from a single image, and each container operates independently.

Characteristics of containers:

• Isolated execution environments

• Fast startup and shutdown

• Can be removed at any time

• Share the host system’s kernel

Because containers are lightweight and flexible, they are well suited for development, testing, and learning environments.

7. The Role of Dockerfile

A Dockerfile is a configuration file used to build Docker images.

It typically defines:

• The base image

• Required packages

• Environment variables

• Execution commands

Using Dockerfiles allows environment configurations to be managed as code, making it possible to reproduce the same environment consistently.

8. Docker Service Structure on Ubuntu

On Ubuntu, Docker is registered as a system service.

• Can start automatically at system boot

• Managed through systemd

• Service status can be checked

This structure enables Docker to operate reliably in server environments.

9. Docker Networking and Storage Concepts

Docker provides features beyond container execution, including networking and data management.

Networking

• Supports communication between containers

• Allows connections to external networks

• Provides a default bridge network

Storage

• Container data is temporary by default

• Volumes enable persistent data storage

• Host directories can be mounted

These capabilities allow Docker to function as a full platform rather than a simple execution tool.

10. Why Learn Docker on Ubuntu?

Learning Docker on Ubuntu offers several benefits:

• Helps in understanding Linux system architecture

• Provides foundational knowledge for server environments

• Introduces automation concepts

• Builds a foundation for cloud and DevOps technologies

Beyond Docker itself, this learning process improves understanding of how systems are structured and managed.

11. Conclusion

Docker operates naturally and efficiently on Ubuntu.

While the installation process may not always be simple, understanding Docker’s internal architecture allows it to be used much more effectively.

By working step by step with images, containers, the Docker Engine, networking, and storage, Docker becomes a platform that helps users gain a deeper understanding of system architecture.