redhat 7.2更新yum源时踩的坑

一、update yum

、先查看redhat7.2中yum的包版本
[root@localhost jiayimeng]#  rpm -qa | grep yum
yum-rhn-plugin-2.0.-.el7.noarch
yum-metadata-parser-1.1.-.el7.x86_64
yum-langpacks-0.4.-.el7.noarch
yum-utils-1.1.-.el7.noarch
yum-3.4.-.el7.noarch

、删除原有的yum包
[root@localhost jiayimeng]# rpm -e yum-rhn-plugin-2.0.-.el7.noarch yum-metadata-parser-1.1.-.el7.x86_64 yum-langpacks-0.4.-.el7.noarch yum-utils-1.1.-.el7.noarch yum-3.4.-.el7.noarch --nodeps
警告：/etc/yum/pluginconf.d/langpacks.conf 已另存为 /etc/yum/pluginconf.d/langpacks.conf.rpmsave

、在各大开源镜像站下载对应包
：
aliyun：
中科大：

、下载并ftp到redhat server
[root@localhost jiayimeng]# ll
总用量
-rw-r--r--.  root root  12月  : yum-3.4.-.el7.centos.noarch.rpm
-rw-r--r--.  root root    12月  : yum-metadata-parser-1.1.-.el7.x86_64.rpm
-rw-r--r--.  root root    12月  : yum-plugin-fastestmirror-1.1.-.el7.noarch.rpm
-rw-r--r--.  root root    12月  : yum-updateonboot-1.1.-.el7.noarch.rpm
-rw-r--r--.  root root   12月  : yum-utils-1.1.-.el7.noarch.rpm

、安装软件包
[root@localhost jiayimeng]# rpm -ivh yum-*
警告：yum-3.4.-.el7.centos.noarch.rpm: 头V3 RSA/SHA256 Signature, 密钥 ID f4a80eb5: NOKEY
错误：依赖检测失败：
    python-urlgrabber >= 3.10- 被 yum-3.4.-.el7.centos.noarch 需要
    rpm >= :4.11.- 被 yum-3.4.-.el7.centos.noarch 需要

、报错，依赖包的版本不符
解决方案有两个，一是在网上找低版本rpm包安装，二是将所依赖的python-urlgrabber和rpm包升级，我这里用第二个方法
----下载----
[root@localhost jiayimeng]# wget http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-4.11.3-25.el7.x86_64.rpm
---- ::--  http://mirrors.163.com/centos/7/os/x86_64/Packages/rpm-4.11.3-25.el7.x86_64.rpm
正在解析主机 mirrors..com (mirrors..com)... 123.58.190.235, 123.58.190.228, 123.58.190.236, ...
正在连接 mirrors..com (mirrors..com)|123.58.190.235|:... 已连接。
已发出 HTTP 请求，正在等待回应...  OK
长度： (1.2M) [application/x-redhat-package-manager]
正在保存至: “rpm-4.11.-.el7.x86_64.rpm”

%[====================>] ,,   .29MB/s 用时 .5s   

-- :: (2.29 MB/s) - 已保存 “rpm-4.11.-.el7.x86_64.rpm” [/])

[root@localhost jiayimeng]# wget http://mirrors.163.com/centos/7/os/x86_64/Packages/python-urlgrabber-3.10-8.el7.noarch.rpm
---- ::--  http://mirrors.163.com/centos/7/os/x86_64/Packages/python-urlgrabber-3.10-8.el7.noarch.rpm
正在解析主机 mirrors..com (mirrors..com)... 123.58.190.235, 123.58.190.234, 123.58.190.237, ...
正在连接 mirrors..com (mirrors..com)|123.58.190.235|:... 已连接。
已发出 HTTP 请求，正在等待回应...  OK
长度： (108K) [application/x-redhat-package-manager]
正在保存至: “python-urlgrabber-3.10-.el7.noarch.rpm”

%[====================>] ,      462KB/s 用时 .2s   

-- :: ( KB/s) - 已保存 “python-urlgrabber-3.10-.el7.noarch.rpm” [/])

----升级----
[root@localhost jiayimeng]# rpm -Uvh rpm-4.11.-.el7.x86_64.rpm --nodeps
警告：rpm-4.11.-.el7.x86_64.rpm: 头V3 RSA/SHA256 Signature, 密钥 ID f4a80eb5: NOKEY
准备中...                          ################################# [%]
正在升级/安装...
   :rpm-4.11.-.el7                ################################# [ %]
正在清理/删除...
   :rpm-4.11.-.el7                ################################# [%]
[root@localhost jiayimeng]# rpm -Uvh python-urlgrabber-3.10-.el7.noarch.rpm --nodeps
警告：python-urlgrabber-3.10-.el7.noarch.rpm: 头V3 RSA/SHA256 Signature, 密钥 ID f4a80eb5: NOKEY
准备中...                          ################################# [%]
正在升级/安装...
   :python-urlgrabber-3.10-.el7     ################################# [ %]
正在清理/删除...
   :python-urlgrabber-3.10-.el7     ################################# [%]

、更新yum源
[root@localhost jiayimeng]# rm /etc/yum.repos.d/redhat.repo
rm：是否删除普通文件 "/etc/yum.repos.d/redhat.repo"？y
[root@localhost jiayimeng]# vim /etc/yum.repos.d/CentOS-Base.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-$ - Base - .com
#mirrorlist=http://mirrorlist.centos.org/?release=$7&arch=$basearch&repo=os
baseurl=http://mirrors.163.com/centos/7/os/$basearch/
gpgcheck=
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7

#released updates
[updates]
name=CentOS-$ - Updates - .com
#mirrorlist=http://mirrorlist.centos.org/?release=$7&arch=$basearch&repo=updates
baseurl=http://mirrors.163.com/centos/7/updates/$basearch/
gpgcheck=
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7

#additional packages that may be useful
[extras]
name=CentOS-$ - Extras - .com
#mirrorlist=http://mirrorlist.centos.org/?release=$7&arch=$basearch&repo=extras
baseurl=http://mirrors.163.com/centos/7/extras/$basearch/
gpgcheck=
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$ - Plus - .com
baseurl=http://mirrors.163.com/centos/7/centosplus/$basearch/
gpgcheck=
enabled=
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7

、清除yum缓存
[root@localhost ~]# yum clean all

、生成缓存
[root@localhost ~]# yum makecache
已加载插件：fastestmirror, product-id, search-disabled-repos,
          : subscription-manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
base                                   | 3.6 kB     :
extras                                 | 3.4 kB     :
updates                                | 3.4 kB     :
(/): base/x86_64/group_gz             |  kB   :
(/): base/x86_64/filelists_db         | 6.7 MB   :
(/): base/x86_64/primary_db           | 5.7 MB   :
(/): base/x86_64/other_db             | 2.5 MB   :
(/): extras/x86_64/prestodelta        |   kB   :
(/): extras/x86_64/filelists_db       |  kB   :
(/): extras/x86_64/other_db           |   kB   :
(/): extras/x86_64/primary_db         |  kB   :
(/): updates/x86_64/prestodelta       |  kB   :
(/): updates/x86_64/filelists_db     | 2.8 MB   :
(/): updates/x86_64/other_db         |  kB   :
(/): updates/x86_64/primary_db       | 4.6 MB   :
Determining fastest mirrors
元数据缓存已建立

二、踩坑

在第6步报错时，我在安装新版本的rpm包时，未使用-Uvh参数，而是使用-ivh参数附加--nodeps，这时安装失败，按照网上的方法，加上了--force参数，导致rpm包依赖出现问题报错为

/usr/lib64/python2.7/site-packages/rpm/_rpm.so: 未定义符号: rpmpkgVerifySigs

   这样的话，水平有限，只能重装解决。总结教训，rpm的强制忽略依赖关系参数易导致版本间出现问题。铭记！