Detailed installation tutorial of Docker under CentOS

Docker is divided into CE and EE. The CE version is the community edition (free); the EE version is the enterprise edition, which emphasizes security (paid). Docker CE releases an edge version every month and a stable version every three months. The version numbers of Docker EE and stable are consistent.

Docker CE supports the 64-bit version of CentOS 7 and requires a kernel version no less than 3.10. CentOS meets the minimum kernel requirements. If the kernel version is lower, some functions (such as the overlay2 storage layer driver) cannot be used, and some functions may be unstable.

There are three ways to install Docker CE: install through the Docker repository, download the installation package and install manually, and install automatically through a script.

• Most users use the mirror source of the Docker repository for installation. This method is relatively simple to install and upgrade, and it is also the recommended method.
• Some users manually install the software by downloading the installation package. This method is useful when you cannot connect to the Internet. You only need the installation package.
• In development and testing environments, some users install through automatic scripts, which is also convenient, but not recommended in production environments. Because it may have the following risks: first, the script requires root privileges, so you need to check the script carefully before running it; second, the script will try to detect the version of your system and configure your package management system. In addition, the script does not allow you to customize any installation parameters. This may result in an unsupported configuration. Furthermore, the script will install dependent packages without confirmation, which may install a large number of packages, depending on your current host configuration; and this method cannot decide the version to download by yourself, it will only install the latest version.

Install using yum source

Official source

$ sudo yum-config-manager \
  --add-repo \
  https://download.docker.com/linux/centos/docker-ce.repo

Domestic Source

$ sudo yum-config-manager \
  --add-repo \
  https://mirrors.ustc.edu.cn/docker-ce/linux/centos/docker-ce.repo

Step 1: Choose one of the two sources above. Generally speaking, due to domestic network problems, domestic sources are usually chosen. But if you are installing Docker CE on your host for the first time, you need to set up the Docker repository first. After that, you can install and update Docker through this repository. Otherwise the following prompt will appear: sudo: yum-config-manager: 找不到命令.

The solution is to set up a repository and install the required package yum-utils . This package provides the functionality of yum-config-manager . Similarly, Docker CE's devicemapper storage driver also requires two other packages device-mapper-persistent-data and lvm2 . We install them together with the following command.

$ sudo yum install -y yum-utils \
 device-mapper-persistent-data \
 lvm2

Install Docker CE

$ sudo yum install docker-ce

During the installation process, you will be asked whether to continue, just enter y.

Automatic installation via script

In order to simplify the installation process in a test or development environment, Docker officially provides a set of convenient installation scripts, which can be used to install on CentOS systems.

$ curl -fsSL get.docker.com -o get-docker.sh
$ sudo sh get-docker.sh -mirror Aliyun

After executing the above command, the script will automatically prepare everything and install the edge version of Docker CE in the system.

Start Docker

The Docker installed in the first way above needs to be started manually, while the installation through the script will automatically start Docker. Starting Docker is also very simple, the following command $ sudo systemctl start docker .

References:

Get Docker CE for CentOS

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