centos6系统从2020年12月1号开始不再维护，官方的yum源不再可用，同时国内的阿里云镜像和163镜像也都不再可用。
但是我们有一些老的服务器仍然在使用centos6系统版本，依赖库的安装和更新就有了问题。
Centos 6.10下载地址 https://mirrors.cloud.tencent.com/centos/6/isos/x86_64/
修改/etc/yum.repos.d/CentOS-Base.repo文件，修改内容如下：
[base]
name=CentOS-6.10
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/os/$basearch/
gpgcheck=1
enabled=1
gpgkey=http://vault.centos.org/RPM-GPG-KEY-CentOS-6
#released updates
[updates]
name=CentOS-6.10
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/updates/$basearch/
gpgcheck=1
enabled=1
gpgkey=http://vault.centos.org/RPM-GPG-KEY-CentOS-6
#additional packages that may be useful
[extras]
name=CentOS-6.10
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/extras/$basearch/
gpgcheck=1
enabled=1
gpgkey=http://vault.centos.org/RPM-GPG-KEY-CentOS-6
name=CentOS-6.10
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/os/$basearch/
gpgcheck=1
enabled=1
gpgkey=http://vault.centos.org/RPM-GPG-KEY-CentOS-6
#released updates
[updates]
name=CentOS-6.10
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/updates/$basearch/
gpgcheck=1
enabled=1
gpgkey=http://vault.centos.org/RPM-GPG-KEY-CentOS-6
#additional packages that may be useful
[extras]
name=CentOS-6.10
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/extras/$basearch/
gpgcheck=1
enabled=1
gpgkey=http://vault.centos.org/RPM-GPG-KEY-CentOS-6
执行命令，刷新缓存
yum clean all
yum makecache
yum update
yum makecache
yum update