Chris Dent
4b89755784
This provides a brief explanation of the new nova-api-wsgi [1] and nova-metadata-wsgi [2] scripts in the Architecture section of the devref with links to the new doc added to the man pages for the eventlet scripts. The nova-api.rst mentioned ec2 so figured best to fix that now rather than forget about it, despite not being entirely germane. There is also a reno note that indicates the availability of the new scripts. There is a devstack change which is testing the new wsgi scripts as well as forcing grenade to not use them at If2d7e363a6541854f2e30c03171bef7a41aff745 [1] I7c4acfaa6c50ac0e4d6de69eb62ec5bbad72ff85 [2] Icb35fe2b94ab02c0ba8ba8129ae18aae0f794756 Change-Id: I351b2af3b256d3031bd2a65feba0495e815f8427 Related-Bug: #1661360
37 lines
1.7 KiB
ReStructuredText
37 lines
1.7 KiB
ReStructuredText
Using WSGI with Nova
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====================
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Though the compute and metadata APIs can be run using independent scripts that
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provide eventlet-based HTTP servers, it is generally considered more performant
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and flexible to run them using a generic HTTP server that supports WSGI_ (such
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as Apache_ or nginx_).
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The nova project provides two automatically generated entry points that
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support this: ``nova-api-wsgi`` and ``nova-metadata-wsgi``. These read
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``nova.conf`` and ``api-paste.ini`` and generate the required module-level
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``application`` that most WSGI servers require. If nova is installed using pip,
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these two scripts will be installed into whatever the expected ``bin``
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directory is for the environment.
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The new scripts replace older experimental scripts that could be found in the
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``nova/wsgi`` directory of the code repository. The new scripts are *not*
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experimental.
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When running the compute and metadata services with WSGI, sharing the compute
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and metadata service in the same process is not supported (as it is in the
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eventlet-based scripts).
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In devstack as of May 2017, the compute and metadata APIs are hosted by a
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Apache communicating with uwsgi_ via mod_proxy_uwsgi_. Inspecting the
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configuration created there can provide some guidance on one option for
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managing the WSGI scripts. It is important to remember, however, that one of
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the major features of using WSGI is that there are many different ways to host
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a WSGI application. Different servers make different choices about performance
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and configurability.
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.. _WSGI: https://www.python.org/dev/peps/pep-3333/
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.. _apache: http://httpd.apache.org/
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.. _nginx: http://nginx.org/en/
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.. _uwsgi: https://uwsgi-docs.readthedocs.io/
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.. _mod_proxy_uwsgi: http://uwsgi-docs.readthedocs.io/en/latest/Apache.html#mod-proxy-uwsgi
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