[openstack-dev] Apache2 vs uWSGI vs ...

Flavio Percoco flavio at redhat.com
Fri Sep 18 14:29:46 UTC 2015


On 18/09/15 06:44 -0700, Morgan Fainberg wrote:
>There is and has been desire to support uWSGI and other alternatives to
>mod_wsgi. There are a variety of operational reasons to consider uWSGI and/or
>gunicorn behind apache most notably to facilitate easier management of the
>processes independently of the webserver itself. With mod_wsgi the processes
>are directly tied to the apache server where as with uWSGI and gunicorn you can
>manage the various services independently and/or with differing VENVs more
>easily. 
>
>There are potential other concerns that must be weighed when considering which
>method of deployment to use. I hope we have clear documentation within the next
>cycle (and possible choices for the gate) for utilizing uWSGI and/or gunicorn. 


+1

FWIW, Zaqar has always been shipped as a wsgi app and the container
the team has recommended ever since it was put in production for the
first time has been uWSGI. uWSGI is already used by Zaqar in the gate
but it's being installed independently.

Flavio

>
>--Morgan
>
>Sent via mobile
>
>On Sep 18, 2015, at 06:12, Adam Young <ayoung at redhat.com> wrote:
>
>
>    On 09/17/2015 10:04 PM, Jim Rollenhagen wrote:
>
>        On Thu, Sep 17, 2015 at 06:48:50PM -0400, Davanum Srinivas wrote:
>
>            In the fuel project, we recently ran into a couple of issues with Apache2 +
>            mod_wsgi as we switched Keystone to run . Please see [1] and [2].
>
>            Looking deep into Apache2 issues specifically around "apache2ctl graceful"
>            and module loading/unloading and the hooks used by mod_wsgi [3]. I started
>            wondering if Apache2 + mod_wsgi is the "right" solution and if there was
>            something else better that people are already using.
>
>            One data point that keeps coming up is, all the CI jobs use Apache2 +
>            mod_wsgi so it must be the best solution....Is it? If not, what is?
>
>        Disclaimer: it's been a while since I've cared about performance with a
>        web server in front of a Python app.
>
>        IIRC, mod_wsgi was abandoned for a while, but I think it's being worked
>        on again. In general, I seem to remember it being thought of as a bit
>        old and crusty, but mostly working.
>
>
>    I am not aware of that.  It has been the workhorse of the Python/wsgi world
>    for a while, and we use it heavily.
>
>
>        At a previous job, we switched from Apache2 + mod_wsgi to nginx + uwsgi[0]
>        and saw a significant performance increase. This was a Django app. uwsgi
>        is fairly straightforward to operate and comes loaded with a myriad of
>        options[1] to help folks make the most of it. I've played with Ironic
>        behind uwsgi and it seemed to work fine, though I haven't done any sort
>        of load testing. I'd encourage folks to give it a shot. :)
>
>
>    Again, switching web servers is as likely to introduce as to solve
>    problems.  If there are performance issues:
>
>    1.  Idenitfy what causes them
>    2.  Change configuration settings to deal with them
>    3.  Fix upstream bugs in the underlying system.
>
>
>    Keystone is not about performance.  Keystone is about security.  The cloud
>    is designed to scale horizontally first.  Before advocating switching to a
>    difference web server, make sure it supports the technologies required.
>
>
>    1. TLS at the latest level
>    2. Kerberos/GSSAPI/SPNEGO
>    3. X509 Client cert validation
>    4. SAML
>
>    OpenID connect would be a good one to add to the list;  Its been requested
>    for a while.
>
>    If Keystone is having performance issues, it is most likely at the database
>    layer, not the web server.
>
>
>
>    "Programmers waste enormous amounts of time thinking about, or worrying
>    about, the speed of noncritical parts of their programs, and these attempts
>    at efficiency actually have a strong negative impact when debugging and
>    maintenance are considered. We should forget about small efficiencies, say
>    about 97% of the time: premature optimization is the root of all evil. Yet
>    we should not pass up our opportunities in that critical 3%."   --Donald
>    Knuth
>     
>
>
>
>        Of course, uwsgi can also be ran behind Apache2, if you'd prefer.
>
>        gunicorn[2] is another good option that may be worth investigating; I
>        personally don't have any experience with it, but I seem to remember
>        hearing it has good eventlet support.
>
>        // jim
>
>        [0] https://uwsgi-docs.readthedocs.org/en/latest/
>        [1] https://uwsgi-docs.readthedocs.org/en/latest/Options.html
>        [2] http://gunicorn.org/
>
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-- 
@flaper87
Flavio Percoco
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