Maybe it works! Create an image with Docker and share it!

Introduction

This article describes how to create a simple container image with Docker and share it with Docker Hub. Since this is a beginner's article, I would appreciate it if you could point out any mistakes.

environment

• macOS Catalina version 10.15.6
• Docker version 19.03.13
• Visual Studio Code version 1.42.1

Prerequisites

You have Docker installed. If you have not installed it, please install it by referring to the link below. Maybe it works! Let's get started with Docker!

Build container image

In order to create a container image, you need to create a Dockerfile that is the contents of the container. Write the following code and save it as Dockerfile.

Docekrfile

FROM ubuntu:20.04
CMD ["echo", "hello Docker!!"]

The content of the code calls the operating system ʻubuntuand outputshello Docker !!`.

In your terminal, go to the Dockerfile directory and hit the docker build command.

$ docker build -t hellodoc .

The -t option allows you to specify an image name. . Indicates the path where the Dockerfile is located. It's . because I'm typing the command in the directory where the Dockerfile is located.

After the build process is finished, try moving the container image.

$ docker run hellodoc

hello Docker!!

It worked fine!

You can see the list of local container images with the docker images command.

$ docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
hellodoc            latest              32d0a84555ac        2 weeks ago         72.9MB

Sharing container images

If you can confirm the operation of the container image, it will just display ~~ hello Docker !! ~~ Let's share the container image with Docker Hub.

Register with Docker Hub

As you can see from the name, Docker Hub is like Docker of Git Hub (personal recognition), and various container images are published.

If you don't have a Docker Hub account, go to the Docker Hub sign-up page (https://hub.docker.com/signup/) and sign up.

Log in to Docker Hub from your terminal.

$ docker login -u ■■■■■■■■■
Password: ************
Login Succeeded

Enter the registered user account in ■ and the password in *.

Sharing container images

Build in a format for sharing container images.

docker build -t ■■■■■■■■■/hellodoc:1.0.0 .

There is a rule in the image name naming convention for sharing.

• Place it under your Docker Hub account name before the image name. (Please change the part of ■ to your own Docker Hub account name.)
• Enter : and the version after the image name.

Register the container image with the docker push command.

$ docker push ■■■■■■■■■/hellodoc:1.0.0

Let's check with Docker Hub when the process is finished. You are registered properly!

Download container image

The registered container image can be downloaded locally with the docker pull command.

docker pull ■■■■■■■■■/hellodoc:1.0.0