Command "/home/alex/.local/share/letsencrypt/bin/python2 -c "import setuptools, tokenize;__file__='/tmp/pip-build-G4N1_U/cryptography/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-crAU1G-record/install-record.txt --single-version-externally-managed --compile --install-headers /home/alex/.local/share/letsencrypt/include/site/python2.7/cryptography" failed with error code 1 in /tmp/pip-build-G4N1_U/cryptography
Using an updated python 2.7 build from stock CentOS 7 2.7.5.