#dockerarchitecture

This article aims to understand the concepts of Docker – A beginner friendly guide to all things – what Docker is, why modern IT industries are opting for this and what makes Docker their choice and if it is the right fit for you.

Ok, here it is, Docker is an open source tool that deals with Containers. And to understand this concept (Containerization) let’s take a peek into the time before Docker.

Before Docker, developers dwelled on Virtual Machines popularized as Virtualization. Virtualization, is the where we used Virtual Systems rather than using actual systems (Systems could be anything from Platforms, Hardware, Shared Computer Resources — Printer, Scanner etc.,) Here the issue was mainly because of its bulky nature and running multiple virtual machines challenged its efficiency. With Dockers creating containers, it was comparatively less burden on the system. In addition, Developers could ship their code into a container and securely run applications anywhere else.

What is Docker?

Docker, an open-source tool that provides platform-as-a-service uses OS virtualization to deliver software in packages called containers. These containers create an ideal environment through necessary provisions and libraries for its content to finish execution.

Docker architecture & how it works?

Being a Client—Server model Docker contains a Client, a Host and a Registry.

The Docker Client performs build and pull operations that let you manage, and manipulate the images and container through a Docker daemon. Docker daemons communicate with each other to maintain services. A daemon processes the API requests for images, containers etc.,

Docker host

The host is where the Containers, images and Docker daemon reside. It provides a complete environment to run your application.

Docker registry

The Docker registry popularly known as the Docker hub works as a repository to manage the images so you can pull or push the Docker images. The docker registry works both online and offline. The Docker hub online backed up by the cloud lets you download images from it or upload them to it with additional privacy. The offline hub benefits the local files. The Docker hub registry checks for required images and if it can’t find the files locally, it downloads from the cloud.

How does the Docker environment work?

The Docker Environment provides ample facilities to get the job done by a container. The Docker file is the text document with necessary functions that a user can call to assemble an image. After the completed process, the developer uses the Docker_build comment to create an automated build, which in the end can be configured and deployed.

Docker image

Docker Images, a read-only template is the means to create a Docker container. The instructions such as ADD, CMD, ENTRYPOINT, ENV, EXPOSE, FROM, MAINTAINER, RUN, USER, VOLUME, WORKDIR are used to build an image. You can pull images from the registry to build containers. The Docker image consists of a Base layer and a Top layer. The base layer is read-only and the top layer is writable. If you are to write in the base layer, the copy of the base layer is created onto the top layer. You can share the base layer as it remains unchanged.

Docker containers

The Docker containers process code in an isolated environment. It contains the required elements for processing (operating system, application code, runtime, system tools and libraries) that can communicate through specific channels and is a lightweight process. Docker containers are made up of Docker images. Usually, the images are in read-only format but the Docker can upgrade the image to read-write file system for build container.

Conclusion