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There are 2 dimensions this discussion should happen in: web server and 
application server. Now we use apache2 as web server and mod_wsgi as app 
server.

I don't have a specific opinion on the app server (mod_wsgi vs uwsgi) and I 
don't really care.

Regarding apache2 vs nginx. I don't see any reasons for the switch. Apache2 is 
well known to deployers and sysadmins. It is very rich for modules. I wonder 
if there are customer-written modules.

On Friday 18 September 2015 16:54:02 Vladimir Kuklin wrote:
> Folks
> 
> I think we do not need to switch to nginx-only or consider any kind of war
> between nginx and apache adherents. Everyone should be able to use
> web-server he or she needs without being pinned to the unwanted one. It is
> like Postgres vs MySQL war. Why not support both?

Why nginx? Why not lighttpd? OpenLitespeed? Litespeed? <insert your web 
server>?

What do you understand by "support both"? I understand it as "both are tested 
in devstack". Apache2 is supported because you can set up devstack and 
everything works.

There are things in keystone that work under apache. They are not tested. They 
were written to work under apache because it's the simplest and the most 
standard way to do. Making them work in nginx means forcing developers write 
some code. You're ready to do that?

> May be someone does not need something that apache supports and nginx not
> and needs nginx features which apache does not support. Let's let our users
> decide what they want.
> 
> And the first step should be simple here - support for uwsgi.

Why uwsgi? Why not gunicorn? Cherrypy? Twisted?

> It will allow
> for usage of any web-server that can work with uwsgi. It will allow also us
> to check for the support of all apache-like bindings like SPNEGO or
> whatever and provide our users with enough info on making decisions. I did
> not personally test nginx modules for SAML and SPNEGO, but I am pretty
> confident about TLS/SSL parts of nginx.
> 
> Moreover, nginx will allow you to do things you cannot do with apache, e.g.
> do smart load balancing, which may be crucial for high-loaded installations.
> On Fri, Sep 18, 2015 at 4:12 PM, 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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-- 
С наилучшими пожеланиями,
Boris