事情起因
系统版本为Centos6.6 ，因为之前同事没有采用最小化选择性安装，所以系统安装好后自带有mysql5.1的三个安装包:
[root@test ~]# rpm -qa | grep mysql
mysql-5.1.73-3.el6_6.x86_64
mysql-devel-5.1.73-3.el6_6.x86_64
mysql-lib-5.1.73-3.el6_6.x86_64
在安装新版本mysql前卸载旧版本
卸载掉了 mysql 和 mysql-devel，但没能成功卸载 mysql-libs，因为存在着依赖关系，所以打算采用rpm更新操作来将其更替：
[root@test ~/Downloads/V137788-01]# rpm -Uvh mysql-commercial-libs-5.7.12-1.1.el6.x86_64.rpm
warning: mysql-commercial-client-5.7.12-1.1.el6.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
error: Failed dependencies:
mysql-commercial-common(x86-64) = 5.7.12-1.1.el6 is needed by mysql-commercial-libs-5.7.12-1.1.el6.x86_64
libmysqlclient.so.16()(64bit) is needed by (installed) postfix-2:2.6.6-6.el6_5.x86_64
libmysqlclient.so.16(libmysqlclient_16)(64bit) is needed by (installed) postfix-2:2.6.6-6.el6_5.x86_64
看来还需要添加上：mysql-commercial-common
[root@test ~/Downloads/V137788-01]# rpm -U mysql-commercial-libs-5.7.12-1.1.el6.x86_64.rpm mysql-commercial-common-5.7.12-1.1.el6.x86_64.rpm
warning: mysql-commercial-libs-5.7.12-1.1.el6.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
error: Failed dependencies:
libmysqlclient.so.16()(64bit) is needed by (installed) postfix-2:2.6.6-6.el6_5.x86_64
libmysqlclient.so.16(libmysqlclient_16)(64bit) is needed by (installed) postfix-2:2.6.6-6.el6_5.x86_64
但是这样还是没能解决，而且卸载postfix会引发更多的rpm包卸载，这样的实施成本就提高了，不是愿意看到的，所以又想到创建本地yum源来更新软件。
安装createrepo包
[root@test ~/Downloads/V137788-01]# yum install -y createrepo
[root@test ~/Downloads/V137788-01]# mkdir /opt/soft; cd /opt/soft/
将mysql的rpm包文件移动到这个目录下
[root@test /opt/soft]# mv ~/Downloads/V137788-01/mysql* ./
=================================================================================
查看[root@test /opt/soft]# ls
libmcrypt-2.5.8-4.3.x86_64.rpm
libmcrypt-devel-2.5.8-4.3.x86_64.rpm
mysql-commercial-client-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-common-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-devel-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-embedded-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-embedded-devel-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-libs-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-libs-compat-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-server-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-test-5.7.12-1.1.el6.x86_64.rpm
nginx-1.9.15-1.el6.icefox.x86_64.rpm
使用createrepo创建本地yum源
这时会在本地yum源目录中多出一个repodata目录(存放有本地yum源的rpm包的文件信息)
[root@test /]# createrepo -v /opt/soft/
[root@test /opt/soft]# ls
libmcrypt-2.5.8-4.3.x86_64.rpm
libmcrypt-devel-2.5.8-4.3.x86_64.rpm
mysql-commercial-client-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-common-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-devel-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-embedded-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-embedded-devel-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-libs-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-libs-compat-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-server-5.7.12-1.1.el6.x86_64.rpm
mysql-commercial-test-5.7.12-1.1.el6.x86_64.rpm
nginx-1.9.15-1.el6.icefox.x86_64.rpm
repodata
编辑repo文件
[root@test /]# vim /etc/yum.repos.d/local.repo
[LC]
name=local-rpm
baseurl=file:///opt/soft
enabled=1
gpgcheck=0
安装新版mysql
[root@test /]# yum install mysql-commercial-libs mysql-commercial-server mysql-commercial-client mysql-commercial-devel
...
Installed:
mysql-commercial-client.x86_64 0:5.7.12-1.1.el6
mysql-commercial-devel.x86_64 0:5.7.12-1.1.el6
mysql-commercial-libs.x86_64 0:5.7.12-1.1.el6
mysql-commercial-libs-compat.x86_64 0:5.7.12-1.1.el6
mysql-commercial-server.x86_64 0:5.7.12-1.1.el6
Dependency Installed:
mysql-commercial-common.x86_64 0:5.7.12-1.1.el6
Replaced:
mysql-libs.x86_64 0:5.1.73-3.el6_5
Complete!
这里问题算是解决了，安装新版mysql并将旧版移除。
总结
1) 在使用createrepo命令创建本地rpm源信息时，要使用绝对路径而非相对路径；
2) 如果有新的软件包需要放在本地yum源中，需要再次执行createrepo更新本地rpm源信息；
3) 本地yum源能很好解决旧版软件间的依赖关系，不再需要手动一步步解决。