yum 安装，可以list，但是无法安装Error downloading packages: 。。。。 No such file or directory

yum 安装，可以list，但是无法安装Error downloading packages: 。。。。 No such file or directory

# yum install nano
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
Resolving Dependencies
--> Running transaction check
---> Package nano.x86_64 :2.3.-.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

=====================================================================================================================================================
 Package                          Arch                               Version                                    Repository                      Size
=====================================================================================================================================================
Installing:
 nano                             x86_64                             2.3.-.el7                               os                              k

Transaction Summary
=====================================================================================================================================================
Install   Package

Total download size:  k
Installed size: 1.6 M
Is this ok [y/d/N]: y
Downloading packages:

Error downloading packages:
  nano-2.3.-.el7.x86_64: [Errno ] [Errno ] No such file or directory

解决方法 ，在下面两个目录开头，把python改为python2

/usr/bin/yum
/usr/libexec/urlgrabber-ext-down

问题原因：

这个是因为系统之前安装python3，原来版本是2.，升级python3建立软连接时把python改为了python2，yum 调用python找不到2.7的版本了