yum install -y yum-utils device-mapper-persistent-data lvm2

 yum list|grep yum

There was a problem importing one of the Python modules

required to run yum. The error leading to this problem was:

   No module named yum

# 查看/usr/bin/yum

more /usr/bin/yum

#!/usr/bin/python

import sys

try:

    import yum

except ImportError:

    print >> sys.stderr, """