检查一下python环境
[root@master ~]# 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

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:
2.7.12 (default, Apr 2 2020, 08:56:50)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-39)]

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

[root@master ~]# whereis python
python: /usr/bin/python2.7 /usr/bin/python /usr/lib/python2.7 /usr/lib64/python2.7 /etc/python /usr/include/python2.7 /usr/local/greenplum-db-6.7.1/ext/python/bin/python /usr/local/greenplum-db-6.7.1/ext/python/bin/python2.7 /usr/local/greenplum-db-6.7.1/ext/python/bin/python2.7-config /usr/share/man/man1/python.1.gz
[root@master ~]#
解决方法：
[root@master ~]# vi .bashrc

.bashrc

User specific aliases and functions

alias rm=‘rm -i’
alias cp=‘cp -i’
alias mv=‘mv -i’

Source global definitions

if [ -f /etc/bashrc ]; then
. /etc/bashrc
fi
#source /usr/local/greenplum-db/greenplum_path.sh
#export MASTER_DATA_DIRECTORY=/data/sd1/master/gpseg-1

2.ls /usr/bin |grep python
[root@master ~]# ls /usr/bin |grep python
python
python2
python2.7
[root@master ~]#
3、
修改yum文件
#vi /usr/bin/yum
[root@master ~]# vi /usr/bin/yum

#!/usr/bin/python
将 #!/usr/bin/python 修改为 #!/usr/bin/python2.7

需要打开新的窗口方可生效。

[root@master ~]# 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

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:
2.7.12 (default, Apr 2 2020, 08:56:50)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-39)]

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