现象

使用yum命令时报如下错误：
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile

base: mirrors.aliyun.com
extras: mirrors.aliyun.com
updates: mirrors.aliyun.com
base | 3.6 kB 00:00:00
extras | 2.9 kB 00:00:00
updates | 2.9 kB 00:00:00
Traceback (most recent call last):
File “/usr/libexec/urlgrabber-ext-down”, line 22, in
from urlgrabber.grabber import
ImportError: No module named urlgrabber.grabber
Traceback (most recent call last):
File “/usr/libexec/urlgrabber-ext-down”, line 22, in
from urlgrabber.grabber import
ImportError: No module named urlgrabber.grabber

由于用户取消而退出

解决方法

原因为python升级后版本不一致导致，需修改如下
vim /usr/libexec/urlgrabber-ext-down，首行python版本改为python2.7
原始文件：

#! /usr/bin/python
#  A very simple external downloader
#  Copyright 2011-2012 Zdenek Pavlas

#   This library is free software; you can redistribute it and/or
#   modify it under the terms of the GNU Lesser General Public
#   License as published by the Free Software Foundation; either
#   version 2.1 of the License, or (at your option) any later version.
#
#   This library is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#   Lesser General Public License for more details.

修改后：

#! /usr/bin/python2.7
#  A very simple external downloader
#  Copyright 2011-2012 Zdenek Pavlas

#   This library is free software; you can redistribute it and/or
#   modify it under the terms of the GNU Lesser General Public
#   License as published by the Free Software Foundation; either
#   version 2.1 of the License, or (at your option) any later version.
#
#   This library is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#   Lesser General Public License for more details.

再运行yum命令即可正常使用