问题：
WARNING: Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by ‘NewConnectionError(’<pip._vendor.urllib3.connection.HTTPConnection object at 0x7fc7fed99400>: Failed to establish a new connection: [Errno 8] nodename nor servname provided, or not known’,)’: /pypi/web/simple/numpy/
解决：
pip install [安装包名] -i http://pypi.douban.com/simple --trusted-host pypi.douban.com
以上亲测，简单好用！！！
来源：oschina
链接：https://my.oschina.net/u/4400968/blog/4330797