yum install 安装某软件时报错：
failure: repodata/repomd.xml from base: [Errno 256] No more mirrors to try.
http://mirrors.163.com/centos/7.8.2003/os/x86_64/repodata/repomd.xml: [Errno 14] HTTP Error 404 - Not Found
解决：
1. 查看centos7系统本身所安装的yum依赖包
rpm -qa|grep yum
yum-plugin-fastestmirror-1.1.31-53.el7.noarch
yum-metadata-parser-1.1.4-10.el7.x86_64
yum-3.4.3-167.el7.centos.noarch
2. 卸载这些软件包
[root@srp-ims ~]# rpm -e yum-plugin-fastestmirror --nodeps
[root@srp-ims ~]# rpm -e yum-metadata-parser --nodeps
[root@srp-ims ~]# rpm -e yum-3.4.3-167.el7.centos.noarch --nodeps
3. 进入centos镜像网站找到自己对应系统需要的yum包
查看系统的命令：
[root@srp-ims ~]# cat /etc/redhat-release
CentOS Linux release 7.8.2003 (Core)
查看系统的位数：
[root@srp-ims ~]# file /bin/ls
/bin/ls: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.32, BuildID[sha1]=aaf05615b6c91d3cbb076af81aeff531c5d7dfd9, stripped
4.下载yum依赖包
[root@srp-ims home]# mkdir software
[root@srp-ims home]# cd software/
[root@srp-ims software]# wget http://vault.centos.org/7.8.2003/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-53.el7.noarch.rpm
[root@srp-ims software]# wget http://vault.centos.org/7.8.2003/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
[root@srp-ims software]# wget http://vault.centos.org/7.8.2003/os/x86_64/Packages/yum-3.4.3-167.el7.centos.noarch.rpm
5. 安装yum依赖包
[root@zf-test-web01-4 ~]# rpm -ivh yum-*
6. 更新centos系统的repo文件
1）首先备份一下
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
2）从http://mirrors.ustc.edu.cn/help/centos.html选择对应版本的 /etc/yum.repos.d/CentOS-Base.repo文件, 放入/etc/yum.repos.d/
我的是CentOS 7：
/etc/yum.repos.d/CentOS-Base.repo 文件:
# # 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=https://mirrors.ustc.edu.cn/centos/$releasever/os/$basearch/ gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7 #released updates [updates] name=CentOS-$releasever - Updates #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates&infra=$infra baseurl=https://mirrors.ustc.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-$releasever - Extras #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras&infra=$infra baseurl=https://mirrors.ustc.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-$releasever - Plus #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus&infra=$infra baseurl=https://mirrors.ustc.edu.cn/centos/$releasever/centosplus/$basearch/ gpgcheck=1 enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
3）清除、再生成缓存
yum clean all
yum makecache
7. 尝试使用yum install 了。