在部署测试环境时，pip install XXX，出现了如下问题：
“File “/usr/lib/python2.7/site-packages/pkg_resources.py”, line 738, in comparison
raise SyntaxError(repr(cop)+” operator not allowed in environment markers”)
SyntaxError: ‘<' operator not allowed in environment markers
error in setup command: Error parsing /opt/stack/cinder/setup.cfg: SyntaxError: '<' operator not allowed in environment markers"
出现这个问题，应该是setuptools版本太旧，需要更新升级，可以执行如下命令来进行升级：
pip install --upgrade pip
pip install --upgrade setuptools