如果你是新安装的centos7的系统直接使用yum install的时候一定会遇到这个报错，Could not retrieve mirrorlist mirrorlist.centos.org/?release=7&…
问题的原因就是centos7的仓库已经被归档，解决方案我们就是使用国内的阿里镜像
接下来将一步步带你解决这个问题
进入/etc/yum.repos.d目录 备份CentOS-Base.repo
cd /etc/yum.repos.d
cp CentOS-Base.repo CentOS-Base.repo.backup
需要改文件内容
vi CentOS-Base.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-$releasever - Base
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os&infra=$infra
#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
#baseurl=http://vault.centos.org/7.9.2009/x86_64/os/
baseurl=http://vault.centos.org/7.9.2009/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
#released updates
[updates]
name=CentOS-$releasever - Updates
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates&infra=$infra
#baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/
#baseurl=http://vault.centos.org/7.9.2009/x86_64/os/
baseurl=http://vault.centos.org/7.9.2009/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras&infra=$infra
#$baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/
#baseurl=http://vault.centos.org/7.9.2009/x86_64/os/
baseurl=http://vault.centos.org/7.9.2009/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus&infra=$infra
#baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/
#baseurl=http://vault.centos.org/7.9.2009/x86_64/os/
baseurl=http://vault.centos.org/7.9.2009/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
然后wq保存下，依次执行：
sudo yum clean all
sudo yum makecache
之后等待加载：
执行完成后进入/etc/yum.repos.d
curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo
然后执行：
cat CentOS-Base.repo
看着镜像是阿里云的即可。建议在执行下
sudo yum clean all
sudo yum makecache
