因为系统检测出漏洞，需升级SSH版本。保险起见，打算在本地搭建相同版本的系统，然后再对本地系统SSH进行升级，没有问题，再对环境进行升级。于是就有了这篇文章，记录了操作过程中遇到的问题。
Centos6.5的最小化安装版本
一、操作系统安装
我是使用的VM安装虚机，但是发现按照一般的安装步骤无法正常进入系统。需要在创建新虚拟机时，勾选稍后选择安装操作系统，否则系统安装重启起来后，可能会卡在系统启动界面。报错如下
/etc/rc5.d/s99local:line 25:eject:command not found
二、配置网络
使用NAT模式，编辑IP地址配置文件/etc/sysconfig/network-scripts/ifcfg-eth0（最后这个eth0根据具体网络接口名修改，有些可能会是ens33等），开机自启，修改协议为dhcp，让系统自动获取IP地址，具体内容如下
[root@bp ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0 DEVICE=eth0 HWADDR=00:0C:29:59:D8:CC TYPE=Ethernet UUID=49b492f8-e204-425b-af70-9a86c497cd92 ONBOOT=yes NM_CONTROLLED=yes BOOTPROTO=dhcp [root@bp ~]#
配置好后重启网络生效
三、Yum源不可用
正常来说，网络配置好，可以ping 8.8.8.8后，就可以正常使用yum源。但是我这次遇到了以下几个问题
（1）Error: Cannot retrieve metalink for repository: epel. Please verify its path and try again
（2）http://download.fedoraproject.org/pub/epel/6/x86_64/repodata/repomd.xml: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found" Trying other mirror.
（3）YumRepo Error: All mirror URLs are not using ftp, http[s] or file
其实这些问题都是Yum源不可用造成的，别的网友查了下centos社区，发现是2020年11月30日开始 centos6各大开源镜像站已经停止维护了 但是测试了一下发现阿里源镜像repo还是可以用的 因为他的centos-vault仓库里放了之前版本的centos的包。所以我这次是通过配置阿里云yum源解决的。参考链接https://blog.csdn.net/u011775882/article/details/110923820
我是将yum源文件内容改成以下内容解决的
[root@bp ~]# cat /etc/yum.repos.d/epel.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-6.10 - Base - mirrors.aliyun.com failovermethod=priority baseurl=http://mirrors.aliyun.com/centos-vault/6.10/os/$basearch/ gpgcheck=1 gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6 #released updates [updates] name=CentOS-6.10 - Updates - mirrors.aliyun.com failovermethod=priority baseurl=http://mirrors.aliyun.com/centos-vault/6.10/updates/$basearch/ gpgcheck=1 gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6 #additional packages that may be useful [extras] name=CentOS-6.10 - Extras - mirrors.aliyun.com failovermethod=priority baseurl=http://mirrors.aliyun.com/centos-vault/6.10/extras/$basearch/ gpgcheck=1 gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6 #additional packages that extend functionality of existing packages [centosplus] name=CentOS-6.10 - Plus - mirrors.aliyun.com failovermethod=priority baseurl=http://mirrors.aliyun.com/centos-vault/6.10/centosplus/$basearch/ gpgcheck=1 enabled=0 gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6 #contrib - packages by Centos Users [contrib] name=CentOS-6.10 - Contrib - mirrors.aliyun.com failovermethod=priority baseurl=http://mirrors.aliyun.com/centos-vault/6.10/contrib/$basearch/ gpgcheck=1 enabled=0 gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6 [root@bp ~]#
修改之后，执行yum clean all和yum makecache即可
原文：https://www.cnblogs.com/biaopei/p/14220282.html