Two years ago, I wrote an article Docker tips for beginners. That’s my first time to learn docker. And after that, I had to move my attention on data crawlers, including Python, Scrapy, Selenium, Chrome Extension, Electron, etc. Today is the day when I am back to work backend again. The first lesson I am learning is how to setup Docker environment. Docket officially claims that docker engine can run the docker image on all platform, including Windows, Linux and Mac. For perosnal and small business usage, it could be free. But if you are working in big company, you have to pay attention on the license, especially for beginners. If you were installing some apps by mistake, it could cause you legal problems.

The Docker Desktop is the product which is recommanded by Docker company to setup the Docker environment. But they also print the Docker Desktop terms on their docker docs page. It’s quite import though it’s a small piece of words.

Docker Desktop terms

Commercial use of Docker Desktop in larger enterprises (more than 250 employees OR more than $10 million USD in annual revenue) and in government entities requires a paid subscription.

Use Docker Safely without Legel Issue

Docker Desktop is not free for all the users. If you are woring in large company which has more than 250 employees or more than $10 million USD in annual revenue, using Docker Desktop will cuase license problem. The alternative option is Docker CE, the Docker Community Edition which is hosted on Github. Basically it’s a package of the Docker Engine and Docker CLI. Starting with the Docker 20.10 release, packages for the Docker Engine and Docker CLI are built directly from their respective source repositories instead of from this repository.

The new Docker CE will seperate the Docker CLI and Docker Engine. Docker CLI build will come from the docker/cli repository and the commit SHA and tag for the Docker Engine will come from the moby/moby repository.

Setup Docker Engine and Run Docker Image

There are huge amounts of articles on the internet to guide us setup Docker Engine and run docker images in Centos. I am following this article. It could be out of date. Please leave your comment if it is invalid one day.

Add Docker Repo Powered by Aliyun

After installing docker ce successfully in CentOS, I always get following error when I run yum command.

Docker Error

Failed connect to download.docker.com:443;

To avoid this error, please update the docker repository address by folloing command:

yum-config-manager --add-repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo