fatal error: Python.h: No such file or directory when installing applications from requirements

[zzxwill]

OS: CentOS Linux release 7.1.1503 (Core)
Python: Python 2.7.5 (default, Nov 20 2015, 02:00:19)

Error:
When running "pip install -r requirements.txt", error occurred.

Collecting fasteners>=0.7 (from oslo.concurrency>=2.3.0->oslo.service>=1.0.0->-r requirements.txt (line 19))
  Using cached fasteners-0.14.1-py2.py3-none-any.whl
Installing collected packages: greenlet, eventlet, WebOb, six, oslo.i18n, msgpack-python, funcsigs, monotonic, wrapt, debtcollector, netifaces, netaddr, iso8601, oslo.utils, oslo.serialization, requests, stevedore, oslo.config, positional, keystoneauth1, python-keystoneclient, oslo.context, pycadf, keystonemiddleware, appdirs, requestsexceptions, os-client-config, openstacksdk, SQLAlchemy, sqlparse, Tempita, sqlalchemy-migrate, MarkupSafe, Mako, python-editor, alembic, oslo.db, python-dateutil, pyinotify, oslo.log, amqp, anyjson, kombu, futures, contextlib2, futurist, retrying, enum34, fasteners, oslo.concurrency, PasteDeploy, repoze.lru, Routes, Paste, oslo.service, cachetools, pika, pika-pool, Jinja2, oslo.middleware, oslo.messaging, oslo.policy, qpid-python
  Running setup.py install for greenlet ... error
    Complete output from command /usr/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-8EKw74/greenlet/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-eA0mUe-record/install-record.txt --single-version-externally-managed --compile:
    running install
    running build
    running build_ext
    building 'greenlet' extension
    creating build
    creating build/temp.linux-x86_64-2.7
    gcc -pthread -fno-strict-aliasing -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -D_GNU_SOURCE -fPIC -fwrapv -DNDEBUG -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -D_GNU_SOURCE -fPIC -fwrapv -fPIC -I/usr/include/python2.7 -c greenlet.c -o build/temp.linux-x86_64-2.7/greenlet.o
    In file included from greenlet.c:5:0:
    greenlet.h:8:20: fatal error: Python.h: No such file or directory
     #include <Python.h>
                        ^
    compilation terminated.
    error: command 'gcc' failed with exit status 1

    ----------------------------------------
Command "/usr/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-8EKw74/greenlet/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-eA0mUe-record/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /tmp/pip-build-8EKw74/greenlet

Analysis:
The root cause might be that installing eventlet depends on python-dev.

[Ayush Garg (ayushgrg93)]

The same error was occurred in my environment too, but it gets resolved by changing the default python from python2.7 to python3.4, and after that updated the tox.

[zzxwill (zzxwill)]

Thank you Ayush. I got some comments from greenlet https://github.com/python-greenlet/greenlet/issues/99.
Python-dev have various distributions, one has to choose the right one for his/her own platform.
 this should not be considered as a bug.

While I am not sure why python3.4 can fix the problem.