安装好CenOS7后，自带的yum不能直接使用，使用会出现如下问题：t
已加载插件：fastestmirror, langpacks File contains no section headers. 已加载插件：fastestmirror, langpacks http://mirrors.aliyun.com/centos/7.8.2003/os/x86_64/repodata/repomd.xml: [Errno 14] HTTP Error 404 - Not Found 正在尝试其它镜像。 To address this issue please refer to the below wiki article
报出404的错误
原因是没有配置yum源，修改/etc/yum.repos.d/CenOS-Base.repo文件内容如下：
# 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/ 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/ 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/ 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/ gpgcheck=1 enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
如果不行，这样，删除原有的文件：
rm -f /etc/yum.repos.d/CentOS-Base.repo
然后重新下载阿里的：
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
清理缓存：
yum clean all
ps:如果上述方法没有解决，尝试下面：
删除yum.repos.d目录下所有文件
rm -f /etc/yum.repos.d/*
然后重新下载阿里的：
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
清理缓存：
yum clean all
测试下载安装：
yum install gcc
原文：https://www.cnblogs.com/cainiao-chuanqi/p/14507491.html