CentOS8 yum install 报错Cannot prepare internal mirrorlist: No URLs in mirrorlist解决（替换yum源）

  yum install openssl失败了，加 --releasever=8参数也失败了

打开/etc/

 

打开看下

 先备份下

mv ./CentOS-Linux-BaseOS.repo ./CentOS-Linux-BaseOS.repo.bak

然后执行

wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.cloud.tencent.com/repo/centos8_base.repo

 清空一下yum缓存

 yum clean all

 然后重建yum缓存

yum makecache

 可以看到，又失败了

我们在替换yum源的时候，按照镜像网站的操作方式，只替换了CentOS-Base.repo。
可是在CentOS8中，CentOS-Linux-AppStream.repo的内容没有更新

最好先备份下，我这边直接修改了

vi ./CentOS-Linux-AppStream.repo 

# CentOS-Linux-AppStream.repo
#
# The mirrorlist system uses the connecting IP address of the client and the
# update status of each mirror to pick current mirrors that are 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, you can try the commented out
# baseurl line instead.

#[appstream]
#name=CentOS Linux $releasever - AppStream
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=AppStream&infra=$infra
#baseurl=http://mirror.centos.org/$contentdir/$releasever/AppStream/$basearch/os/
#gpgcheck=1
#enabled=1
#gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial

[appstream]
name=Qcloud centos AppStream - $basearch
baseurl=http://mirrors.cloud.tencent.com/centos/$releasever/AppStream/$basearch/os/
enabled=1
gpgcheck=1
gpgkey=http://mirrors.cloud.tencent.com/centos/RPM-GPG-KEY-CentOS-Official
~                                                                                                                                                                                                                              
~                                                                       

将原来的[appstream]注释掉，然后修改，wq保存

然后再执行重建yum缓存

yum makecache

 可以看到，源数据缓存已经建立

接下来继续执行yum install即可

 可以看到，已经执行成功了

也可以将CentOS-Linux-AppStream.repo删除，不推荐，注意有的版本叫CentOS-Base.repo和CentOS-AppStream.repo

还有[appstream]有的版本是大写[AppStream]

另附两个源地址

阿里yum源： https://developer.aliyun.com/mirror/centos
腾迅yum源： https://mirrors.tencent.com/help/centos.html

至此问题解决

如果还不行可以查看下网卡配置里的DNS可以先配置为8.8.8.8试一下，或者修改/etc/resolv.conf里的nameserver为8.8.8.8

再不行就是网络受限了，加代理或者解决网络问题