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This article will explain in detail what are the three elements of docker. The editor thinks it is very practical, so I share it for you as a reference. I hope you can get something after reading this article.

Three elements of docker

Images, containers, warehouses

Mirror image

The docker image is a read-only template. Images can be used to create docker containers, and one image can create many containers.

Container

Docker uses a container (container) to run an application or a group of applications independently. A container is a running instance created with a mirror (as opposed to the concept of classes and objects in Python).

It can be started, started, stopped, and deleted. Each container is isolated from each other and ensures a secure platform.

Think of the container as a simple version of the Linux environment (including root username permissions, process space, user space, cyberspace, etc.) and applications running in it.

The definition and image of the container are almost the same, and it is also a unified perspective of a bunch of layers. the only difference is that the top part of the container is readable and writable.

Warehouse

A repository is a place where images are stored centrally.

There is a difference between warehouse (repository) and warehouse registration server (registry). There are often many repositories on the warehouse registration server, and each warehouse contains many images, each with a different tag.

Warehouses are divided into public warehouses (public) and private warehouses (private).

The largest public repository is docker hub (https://hub.docker.com/), which stores a large number of images for users to download. Domestic public warehouses include Aliyun, NetYiyun and so on.

Summary:

You need to correctly understand the three concepts of warehouse, image and container:

Docker itself is a container runner or supervisor engine. We package the application and configuration dependencies to form a deliverable runtime environment called the image image file. The docker container can only be generated from this image file. The image file can be thought of as a template for the container. Docker generates an instance of the container based on the image file. Multiple container instances running at the same time can be generated from the same image file.

A) the container instance generated by the image file is itself a file, called an image file

B) A container runs a service, and when we need it, we can create a corresponding running instance through the docker client, that is, our container

C) as for the warehouse, where we put a bunch of images, we can publish the images to the repository and pull them down when needed.

This is the end of the article on "what are the three elements of docker". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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