因為系統檢測出漏洞，需升級SSH版本。保險起見，打算在本地搭建相同版本的系統，然后再對本地系統SSH進行升級，沒有問題，再對環境進行升級。於是就有了這篇文章，記錄了操作過程中遇到的問題。
Centos6.5的最小化安裝版本
一、操作系統安裝
我是使用的VM安裝虛機，但是發現按照一般的安裝步驟無法正常進入系統。需要在創建新虛擬機時，勾選稍后選擇安裝操作系統，否則系統安裝重啟起來后，可能會卡在系統啟動界面。報錯如下
/etc/rc5.d/s99local:line 25:eject:command not found
二、配置網絡
使用NAT模式，編輯IP地址配置文件/etc/sysconfig/network-scripts/ifcfg-eth0（最后這個eth0根據具體網絡接口名修改，有些可能會是ens33等），開機自啟，修改協議為dhcp，讓系統自動獲取IP地址，具體內容如下
[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 ~]#
配置好后重啟網絡生效
三、Yum源不可用
正常來說，網絡配置好，可以ping 8.8.8.8后，就可以正常使用yum源。但是我這次遇到了以下幾個問題
（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
其實這些問題都是Yum源不可用造成的，別的網友查了下centos社區，發現是2020年11月30日開始 centos6各大開源鏡像站已經停止維護了 但是測試了一下發現阿里源鏡像repo還是可以用的 因為他的centos-vault倉庫里放了之前版本的centos的包。所以我這次是通過配置阿里雲yum源解決的。參考鏈接https://blog.csdn.net/u011775882/article/details/110923820
我是將yum源文件內容改成以下內容解決的。如果還有報錯，可以嘗試把該目錄下其他repo文件刪掉
[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，執行yum clean all和yum makecache即可
