由于CentOS8默认安装了podman，因此在CentOS8中安装docker会导致冲突引发如下异常。

Error: 
 Problem 1: problem with installed package podman-2.0.5-5.module_el8.3.0+512+b3b58dca.x86_64
  - package podman-2.0.5-5.module_el8.3.0+512+b3b58dca.x86_64 requires runc >= 1.0.0-57, but none of the providers can be installed
  - package containerd.io-1.4.3-3.1.el8.x86_64 conflicts with runc provided by runc-1.0.0-68.rc92.module_el8.3.0+475+c50ce30b.x86_64
  - package containerd.io-1.4.3-3.1.el8.x86_64 obsoletes runc provided by runc-1.0.0-68.rc92.module_el8.3.0+475+c50ce30b.x86_64
  - cannot install the best candidate for the job
  - package runc-1.0.0-64.rc10.module_el8.3.0+479+69e2ae26.x86_64 is filtered out by modular filtering
 Problem 2: problem with installed package buildah-1.15.1-2.module_el8.3.0+475+c50ce30b.x86_64
  - package buildah-1.15.1-2.module_el8.3.0+475+c50ce30b.x86_64 requires runc >= 1.0.0-26, but none of the providers can be installed
  - package docker-ce-3:20.10.1-3.el8.x86_64 requires containerd.io >= 1.4.1, but none of the providers can be installed
  - package containerd.io-1.4.3-3.1.el8.x86_64 conflicts with runc provided by runc-1.0.0-68.rc92.module_el8.3.0+475+c50ce30b.x86_64
  - package containerd.io-1.4.3-3.1.el8.x86_64 obsoletes runc provided by runc-1.0.0-68.rc92.module_el8.3.0+475+c50ce30b.x86_64
  - package containerd.io-1.4.1-3.1.el8.x86_64 conflicts with runc provided by runc-1.0.0-68.rc92.module_el8.3.0+475+c50ce30b.x86_64
  - package containerd.io-1.4.1-3.1.el8.x86_64 obsoletes runc provided by runc-1.0.0-68.rc92.module_el8.3.0+475+c50ce30b.x86_64
  - package containerd.io-1.4.3-3.el8.x86_64 conflicts with runc provided by runc-1.0.0-68.rc92.module_el8.3.0+475+c50ce30b.x86_64
  - package containerd.io-1.4.3-3.el8.x86_64 obsoletes runc provided by runc-1.0.0-68.rc92.module_el8.3.0+475+c50ce30b.x86_64
  - cannot install the best candidate for the job
  - package runc-1.0.0-56.rc5.dev.git2abd837.module_el8.3.0+569+1bada2e4.x86_64 is filtered out by modular filtering
  - package runc-1.0.0-64.rc10.module_el8.3.0+479+69e2ae26.x86_64 is filtered out by modular filtering

在部分场景中却不得不使用docker，因为podman是新东西，即便命令和docker及其相似，也因为生态原因，各类API还无法完全兼容。例如《【视频教程】Electron自动编译及自动更新、分发》就对这个情况进行过说明，在使用Electron 应用分发系统的时候，由于使用了开源项目dockerode对docker进行控制，因此需要卸载podman改用docker。

卸载podman

yum -y erase podman buildah

卸载完成后无需重启，可直接安装docker。

注： 如果不是迫不得已，推荐大家使用podman，和docker命令非常相似。

安装Docker

curl -fsSL https://get.docker.com -o get-docker.sh && sh get-docker.sh

国内设备使用阿里云加速安装：

curl -fsSL https://get.docker.com -o get-docker.sh && sh get-docker.sh --mirror Aliyun

以上命令会自动判断所在的环境，适用于大部分*unix操作系统和架构。包括Raspberry Pi等ARM架构的设备。

如果你希望以非root用户运行docker，安装完成后添加用户到docker组：

sudo usermod -aG docker your-user

设置开机启动：

systemctl enable docker

启动docker：

systemctl start docker