在python下执行pip install，报错：

$ ./pip install pyopenssl ndg-httpsclient pyasn1
Collecting pyopenssl
Could not fetch URL https://pypi.python.org/simple/pyopenssl/: There was a problem confirming the ssl certificate: [Errno 1] _ssl.c:499: error:1407742E:SSL routines:SSL23_GET_SERVER_H ELLO:tlsv1 alert protocol version – skipping
C:\Python27\lib\site-packages\pip-9.0.1-py2.7.egg\pip\_vendor\requests\packages\urllib3\util\ssl_.py:318: SNIMissingWarning: An HTTPS request has been made, but the SNI (Subject Name In dication) extension to TLS is not available on this platform. This may cause the server to present an incorrect TLS certificate, which can cause validation failures. You can upgrade to a newer version of Python to solve this. For more information, see https://urllib3.readthedocs.io/en/latest/security.html#snimissingwarning.
SNIMissingWarning
C:\Python27\lib\site-packages\pip-9.0.1-py2.7.egg\pip\_vendor\requests\packages\urllib3\util\ssl_.py:122: InsecurePlatformWarning: A true SSLContext object is not available. This preven ts urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. You can upgrade to a newer version of Python to solve this. For more information, see https: //urllib3.readthedocs.io/en/latest/security.html#insecureplatformwarning.
InsecurePlatformWarning
Could not find a version that satisfies the requirement pyopenssl (from versions: )
No matching distribution found for pyopenssl
C:\Python27\lib\site-packages\pip-9.0.1-py2.7.egg\pip\_vendor\requests\packages\urllib3\util\ssl_.py:122: InsecurePlatformWarning: A true SSLContext object is not available. This preven ts urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. You can upgrade to a newer version of Python to solve this. For more information, see https: //urllib3.readthedocs.io/en/latest/security.html#insecureplatformwarning.
InsecurePlatformWarning

alading@venus MINGW64 /c/Python27/Scripts

最后查原因是python版本低了，老版本中的tls 1.0版本ssl不再支持，需要更新python2.7到最后一个版本。这里更新到python 2.7.14 解决。
$ ./pip.exe install redis
Collecting redis
Downloading https://files.pythonhosted.org/packages/3b/f6/7a76333cf0b9251ecf49efff635015171843d9b977e4ffcf59f9c4428052/redis-2.10.6-py2.py3-none-any.whl (64kB)
Installing collected packages: redis
Successfully installed redis-2.10.6
You are using pip version 9.0.1, however version 10.0.1 is available.
You should consider upgrading via the ‘python -m pip install –upgrade pip’ command.