1. 如果你熟悉docker, 就没必要每次都去一个一个命令开始复制 粘贴 执行 浪费时间.  直接把整理好的所有命令放入一次执行即可.
2. 如果你是小白, 需要直接搭建环境成功,看到直观效果, 这里就可以. 可以增长信息,提升学习兴趣. 不至于浪费时间太多,热情冷却.

#Uninstall old versionsO#lder versions of Docker were called docker or docker-engine. If these are installed, uninstall them, along with associated sudo yum remove docker \                  docker-client \                  docker-client-latest \                  docker-common \                  docker-latest \                  docker-latest-logrotate \                  docker-logrotate \                  docker-selinux \                  docker-engine-selinux \                  docker-engine#SET UP THE REPOSITORY#Install required packages. yum-utils provides the yum-config-manager utility, and device-mapper-persistent-data and lvm2 are required by the devicemapper storage driver. sudo yum install -y yum-utils \  device-mapper-persistent-data \  lvm2#Use the following command to set up the stable repository. You always need the stable repository, even if you want to install builds from the edge or test repositories as well. sudo yum-config-manager \    --add-repo \    https://download.docker.com/linux/centos/docker-ce.repo#Optional: Enable the edge and test repositories. These repositories are included in the docker.repo file above but are disabled by default. You can enable them alongside the stable repository.sudo yum-config-manager --enable docker-ce-edgesudo yum-config-manager --enable docker-ce-test#You can disable the edge or test repository by running the yum-config-manager command with the --disable flag. To re-enable it, use the --enable flag. The following command disables the edge repository.sudo yum-config-manager --disable docker-ce-edge#INSTALL DOCKER CE#Install the latest version of Docker CE, or go to the next step to install a specific version:sudo yum install docker-ce#If prompted to accept the GPG key, verify that the fingerprint matches 060A 61C5 1B55 8A7F 742B 77AA C52F EB6B 621E 9F35, and if so, accept it#Got multiple Docker repositories?#If you have multiple Docker repositories enabled, installing or updating without specifying a version in the yum install or yum update command always installs the highest possible version, which may not be appropriate for your stability needs.#Docker is installed but not started. The docker group is created, but no users are added to the group.#To install a specific version of Docker CE, list the available versions in the repo, then select and install:#a. List and sort the versions available in your repo. This example sorts results by version number, highest to lowest, and is truncated:yum list docker-ce --showduplicates | sort -r#Start Docker.sudo systemctl start docker#Verify that docker is installed correctly by running the hello-world image. sudo docker run hello-world

#Run this command to download the latest version of Docker Compose:sudo curl -L "https://github.com/docker/compose/releases/download/1.22.0/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose#Apply executable permissions to the binary:sudo chmod +x /usr/local/bin/docker-compose#Test the installation.docker-compose --version