一、安装yum源

1.卸载yum

# 查看系统自身安装的yum软件包
rpm -qa | grep yum
# 卸载软yum件包
rpm -e 软件包名称 --nodeps  #可以使用简称如 rpm -e yum-* --nodeps

2. 安装yum

[root@bogon ~]# rpm -ivh --nodeps https://mirrors.aliyun.com/centos/8/BaseOS/x86_64/os/Packages/yum-4.2.23-4.el8.noarch.rpm 

3. 添加yum源

可以通过下载或文本编辑安装。

注意docker安装并未使用该yum源，因为报错了。不过添加后可以安装其他软件。

1）.添加下载的方式添加

# 切换到yum源目录
/etc/yum.repos.d
# 下载或拷贝yum源文件
wget http://mirrors.aliyun.com/repo/Centos-8.repo?spm=a2c6h.25603864.0.0.3d975969k0L4KM

2).用文本编辑

# 编辑前如果文件已存在，则添加
vi /etc/yum.repos.d/Centos-8.repo

# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client.  You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the 
# remarked out baseurl= line instead.
#
#[base]
name=CentOS-$releasever - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=https://mirrors.aliyun.com/centos/$releasever/BaseOS/$basearch/os/http://mirrors.aliyuncs.com/centos/$releasever/BaseOS/$basearch/os/http://mirrors.cloud.aliyuncs.com/centos/$releasever/BaseOS/$basearch/os/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - mirrors.aliyun.com
failovermethod=priority
baseurl=https://mirrors.aliyun.com/centos/$releasever/extras/$basearch/os/http://mirrors.aliyuncs.com/centos/$releasever/extras/$basearch/os/http://mirrors.cloud.aliyuncs.com/centos/$releasever/extras/$basearch/os/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - mirrors.aliyun.com
failovermethod=priority
baseurl=https://mirrors.aliyun.com/centos/$releasever/centosplus/$basearch/os/http://mirrors.aliyuncs.com/centos/$releasever/centosplus/$basearch/os/http://mirrors.cloud.aliyuncs.com/centos/$releasever/centosplus/$basearch/os/
gpgcheck=1
enabled=0
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official[PowerTools]
name=CentOS-$releasever - PowerTools - mirrors.aliyun.com
failovermethod=priority
baseurl=https://mirrors.aliyun.com/centos/$releasever/PowerTools/$basearch/os/http://mirrors.aliyuncs.com/centos/$releasever/PowerTools/$basearch/os/http://mirrors.cloud.aliyuncs.com/centos/$releasever/PowerTools/$basearch/os/
gpgcheck=1
enabled=0
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official[AppStream]
name=CentOS-$releasever - AppStream - mirrors.aliyun.com
failovermethod=priority
baseurl=https://mirrors.aliyun.com/centos/$releasever/AppStream/$basearch/os/http://mirrors.aliyuncs.com/centos/$releasever/AppStream/$basearch/os/http://mirrors.cloud.aliyuncs.com/centos/$releasever/AppStream/$basearch/os/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
[root@bogon yum.repos.d]# 

二、.安装docker

yum install -y docker

直接使用会报错：

containers-common-2:1-2.module_el8.5.0+890+6b136101.noarch conflicts with file from package redhat-release-8.5-0.8.el8

所以采用以下安装方式：

1.更新yum

yum update

2.卸载旧版本的docker

yum remove docker docker-common docker-selinux docker-engine

3. 安装依赖的软件包

yum install -y yum-utils device-mapper-persistent-data lvm2

4.设置yum 源

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

5. 不设定版本安装lasted Docker

yum install --allowerasing docker-ce docker-ce-cli containerd.io

6. 安装校验

systemctl start docker 
# 查看docker版本docker version
# 或
docker info

参考资料：
http://mirrors.aliyun.com/repo/
https://blog.csdn.net/sinat_31633205/article/details/115004764?spm=1001.2014.3001.5506
https://blog.csdn.net/Monster_WangXiaotu/article/details/122590389