yum升级时，报错：

There was a problem importing one of the Python modules
required to run yum. The error leading to this problem was:

   libiconv.so.2: cannot open shared object file: No such file or directory

Please install a package which provides this module, or
verify that the module is installed correctly.

It's possible that the above module doesn't match the
current version of Python, which is:
2.6.6 (r266:84292, Aug 18 2016, 14:53:48)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-17)]

If you cannot solve this problem yourself, please go to
the yum faq at:
  http://yum.baseurl.org/wiki/Faq

然后想起昨天编译安装libiconv了，难道没安装好？

参考：https://amon.org/libiconv

于是重新编译安装一次后，查看这个文件是否存在：

find / -name "libiconv.so.2" -print

输出：

/usr/local/lib/libiconv.so.2
/root/libiconv-1.15/lib/.libs/libiconv.so.2

文件存在啊，可问题依然。

参考：http://forum.amule.org/index.php?topic=4715.0

更新系统动态连接库配置：

echo /usr/local/lib >> /etc/ld.so.conf && ldconfig

然后执行yum，问题解决。