出现错误

已加载插件：fastestmirror Determining fastest mirrors Could not retrieve
mirrorlist
http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock
error was 14: curl#6 - “Could not resolve host: mirrorlist.centos.org;
                            

原因是镜像源已经不支持了centos7太老了

解决方案

删除原来的镜像

rm /etc/yum.repos.d/CentOS-Base.repo

建立新的

vim /etc/yum.repos.d/CentOS-Base.repo

粘贴进去

  
[base]  
name=CentOS-$releasever - Base  
baseurl=http://mirrors.aliyun.com/centos/$releasever/os/$basearch/  
        http://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/os/$basearch/  
gpgcheck=1  
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7  
  
#released updates   
[updates]  
name=CentOS-$releasever - Updates  
baseurl=http://mirrors.aliyun.com/centos/$releasever/updates/$basearch/  
        http://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/updates/$basearch/  
gpgcheck=1  
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7  
  
#additional packages that may be useful  
[extras]  
name=CentOS-$releasever - Extras  
baseurl=http://mirrors.aliyun.com/centos/$releasever/extras/$basearch/  
        http://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/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-$releasever - Plus  
baseurl=http://mirrors.aliyun.com/centos/$releasever/centosplus/$basearch/  
        http://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/centosplus/$basearch/  
gpgcheck=1  
enabled=0  
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7  
  
#contrib - packages by Centos Users  
[contrib]  
name=CentOS-$releasever - Contrib  
baseurl=http://mirrors.aliyun.com/centos/$releasever/contrib/$basearch/  
        http://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/contrib/$basearch/  
gpgcheck=1  
enabled=0  
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7  
  
# 使用failovermethod指定优先级，这里设置为随机（roundrobin），也可以改为priority并指定每个URL的优先级  
failovermethod=roundrobin

在运行

sudo /sbin/dhclient