Get Docker for CentOS and Installing Docker

1、OS requirements

To install Docker, you need the 64-bit version of CentOS 7.

2、Uninstall old versions

Older versions of Docker were called docker or docker-engine. If these are installed, uninstall them, along with associated dependencies.$ sudo yum remove docker

                  docker-common 
                  container-selinux 
                  docker-selinux 
                  docker-engine

3、Install using the repository(Docker CE)

(1) Install yum-utils, which provides the yum-config-manager utility:

　　$ sudo yum install -y yum-utils

(2) Use the following command to set up the stable repository. You always need the stablerepository, even if you want to install edge builds as well.

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

(3) Optional: Enable the edge repository. This repository is included in the docker.repo file above but is disabled by default. You can enable it alongside the stable repository.

$ sudo yum-config-manager --enable docker-ce-edge

4、INSTALL DOCKER

(1) Update the yum package index.

$ sudo yum makecache fast

(2) Install the latest version of Docker, or go to the next step to install a specific version.

Docker Edition	Command
Docker CE	sudo yum install docker-ce
Docker EE	sudo yum install docker-ee

(3) On production systems, you should install a specific version of Docker instead of always using the latest. List the available versions. This example uses the sort -r command to sort the results by version number, highest to lowest, and is truncated.

　　yum list docker-ce.x86_64 --showduplicates |sort -r

(4) Start Docker.

sudo systemctl start docker

(5) Verify that docker is installed correctly by running the hello-world image.

$ sudo docker run hello-world