依次运行以下命令：
cd /etc/yum.repos.d
wget http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
yum -y install docker-ce docker-ce-cli
systemctl restart docker
systemctl enable docker
如果没有wget命令，得先yum install wget安装。
centos 8上遇到的问题
在centos 8上，并没有得到预期的结果，得到如下错误信息：
Error:
Problem: package docker-ce-3:19.03.12-3.el7.x86_64 requires containerd.io >= 1.2.2-3, but none of the providers can be installed
- cannot install the best candidate for the job
- package containerd.io-1.2.10-3.2.el7.x86_64 is filtered out by modular filtering
- package containerd.io-1.2.13-3.1.el7.x86_64 is filtered out by modular filtering
- package containerd.io-1.2.13-3.2.el7.x86_64 is filtered out by modular filtering
- package containerd.io-1.2.2-3.3.el7.x86_64 is filtered out by modular filtering
- package containerd.io-1.2.2-3.el7.x86_64 is filtered out by modular filtering
- package containerd.io-1.2.4-3.1.el7.x86_64 is filtered out by modular filtering
- package containerd.io-1.2.5-3.1.el7.x86_64 is filtered out by modular filtering
- package containerd.io-1.2.6-3.3.el7.x86_64 is filtered out by modular filtering
错误的原因是：
centos8的yum库中没有符合最新版docker-ce对应版本的containerd.io，docker-ce-3:19.03.11-3.el7.x86_64需要containerd.io >= 1.2.2-3
因此，需要先安装对应的containerd.io
yum install -y https://mirrors.aliyun.com/docker-ce/linux/centos/7/x86_64/edge/Packages/containerd.io-1.2.13-3.2.el7.x86_64.rpm
然后再运行yum -y install docker-ce docker-ce-cli即可完成docker的安装。
