Introduction to Docker

What is Docker?

Docker is a container orchestration tool, which is used for developing, shipping, and running applications as a lightweight, portable, self-sufficient container. In addition, Docker containers are easy to deploy. It is used to automate the deployment of the application in lightweight containers so the application can work efficiently in different environments.

Why Docker?

Differences between docker containers and virtual machines- the virtual machine has its's guest operating system. On the other hand, Docker containers share the host operating system, and that is why they are lightweight. Docker containers are easily portable as they have share host os while on the other hand, virtual machines have separate os. As compare to docker container virtual machines are difficult to port. Virtual machines can also be slow to boot.

Components of Docker:

• Docker client and daemon - Docker client is docker CLI, which sends commands to the docker daemon. Docker daemon listens to Docker API requests to manage docker objects like containers and images.
• Docker container - Docker container is a standalone, executable software package that allows developers to isolate their app from its environment. A container is defined by its image as well as any configuration options you provide to it when you create or start it. Using docker CLI you can create, run, remove, attach, stop the docker container. The container can connect one or more networks.
• Docker Images - Docker image is portable template with instructions to create docker containers. You can create your own docker image using Dockerfile, from your docker container also, you can use created docker images by others and published on the registry. A Docker image is made up of multiple layers. Dockerfile includes set of instructions, each instruction creates a different layer.
• Docker registry - A Docker registry used for hosting and distributing Docker images. Docker Hub is a public registry, docker user can pull or push docker images from the configured registry. There are other choices such as Google, Azure, or AWS Container Registry. Also, they can store images in private or public repositories. A Docker Repository is a collection of related images with the same name, that have different tags.

Docker Installation:

Please refer the official site for Docker installation: https://docs.docker.com/get-docker/

Stay tuned for the upcoming blog on basic and important commands in docker.

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