Docker Architecture

5 min readApr 20, 2024

Imagine you have multiple computers inside your computer, each running its own operating system. They’re like separate houses, each with their own furniture and utilities. They’re good for keeping things completely separate, but they’re heavy and take up a lot of space are your Virtual Machines

On the other end Docker, Picture small, self-contained boxes that hold just what an application needs to run. They all share the same basic resources, like a big apartment building with separate apartments. They’re quick to set up and tear down, and they don’t take up much space.

What is Docker? — Docker is like a magic box for software

Let me explain, It lets developers pack up their applications and everything they need to run into a neat little package called a container.

These containers can run on any computer that has Docker installed, making it super easy to move applications between different machines.

It’s kind of like moving houses — instead of packing up all your stuff and rebuilding everything from scratch, you just pick up your container and plop it down wherever you want to go. It’s fast, efficient, and keeps everything tidy.

Docker is an open-source platform that makes it easy to create containers and container-based apps.

Let's Understand Docker Architecture:

Docker architecture revolves around a client-server model, with three main components:

1. Docker Client:

This is the primary interface through which users interact with Docker. Users issue commands to the Docker client, which then communicates with the Docker daemon to execute those commands.

2. Docker Daemon:

This is a background service that manages Docker containers. It is responsible for building, running, and distributing Docker containers. The daemon listens for Docker API requests and manages container objects such as images, containers, networks, and volumes.

3. Docker Registry:

The Docker registry is a repository for Docker images. It stores Docker images that are used to create Docker containers. The default public registry for Docker is Docker Hub, but users can also set up their private registries for hosting and sharing Docker images within their organization.

In Simple Words:

Docker Engine: This is the heart of Docker. It’s like the construction manager that oversees everything. The Docker Engine includes:

Docker Daemon: This is a background process that manages Docker objects like containers, images, networks, and volumes.
REST API: It’s like the communication system that allows you to interact with the Docker Daemon and give it commands.
CLI (Command Line Interface): This is the tool you use to talk to Docker. You give it commands, and it talks to the Docker Daemon for you.

There are four Docker Components:

1. Docker image :

A Docker image is a lightweight, standalone, and executable package that contains everything needed to run a piece of software, including the code, runtime, libraries, dependencies, and configuration files. It serves as a template for creating Docker containers, which are the runtime instances of Docker images.

Standalone: Docker images are self-contained units that include all the necessary components to run an application.
Built from Dockerfile: Docker images are typically built from a Dockerfile, which is a text file that contains instructions for assembling the image.
Stored in Registries: Docker images are stored in repositories known as Docker registries. The default public registry is Docker Hub. You can pull images from the docker hub to create containers.

2. Docker Container:

A Docker container is a lightweight, portable, and self-contained runtime instance of a Docker image. It encapsulates an application and its dependencies, providing an isolated environment for running the application consistently across different platforms and environments.

3. Docker Network:

Docker Network refers to the networking functionality provided by Docker to facilitate communication between Docker containers, between containers and the host system, and between containers and external networks. Docker networking allows containers to communicate with each other and with external systems, enabling the development of complex distributed applications.

4. Docker Volumes:

A Docker volume is a persistent data storage mechanism that allows containers to store and share data independently of the container lifecycle. Volumes provide a way to persist data generated by containers, share data between containers, and enable data persistence when containers are stopped or removed.