Cleanest & Fastest server setup for Django [closed] - python

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I'm about to deploy a mediumsized site powered by Django. I have a dedicated Ubuntu Server.
I'm really confused over which serversoftware to use. So i thought to myself: why not ask stackoverflow.
What i'm looking for is:
Easy to set up
Fast and easy on resources
Can serve mediafiles
Able to serve multiple djangosites on same server
I would rather not install PHP or anything else that sucks resources, and for which I have no use for.
I have heard of mod_wsgi and mod_python on Apache, nginx and lighty. Which are the pros and cons of these and have i missed someone?
#Barry: Somehow i feel like Apache is to bloated for me. What about the alternatives?
#BrianLy: Ok I'll check out mod_wsgi some more. But why do i need Apache if i serve static files with lighty? I have also managed to serve the django app itself with lighty. Is that bad in anyway? Sorry for beeing so stupid :-)
UPDATE: What about lighty and nginx - which are the uses-cases when these are the perfect choice?

Since I was looking for some more in-depth answers, I decided to research the issue myself in depth. Please let me know if I've misunderstood anything.
Some general recommendation are to use a separate webserver for handling media. By separate, I mean a webserver which is not running Django. This server can be for instance:
Lighttpd (Lighty)
Nginx (EngineX)
Or some other light-weight server
Then, for Django, you can go down different paths. You can either:
Serve Django via Apache and:
mod_python
This is the stable and recommended/well documented way. Cons: uses a lot of memory.
mod_wsgi
From what I understand, mod_wsgi is a newer alternative. It appears to be faster and easier on resources.
mod_fastcgi
When using FastCGI you are delegating the serving of Django to another process. Since mod_python includes a python interpreter in every request it uses a lot of memory. This is a way to bypass that problem. Also there is some security concerns.
What you do is that you start your Django FastCGI server in a separate process and then configures apache via rewrites to call this process when needed.
Or you can:
Serve Django without using Apache but with another server that supports FastCGI natively:
(The documentation mentions that you can do this if you don't have any Apache specific needs. I guess the reason must be to save memory.)
Lighttpd
This is the server that runs Youtube. It seems fast and easy to use, however i've seen reports on memoryleaks.
nginx
I've seen benchmarks claiming that this server is even faster than lighttpd. It's mostly documented in Russian though.
Another thing, due to limitations in Python your server should be running in forked mode, not threaded.
So this is my current research, but I want more opinions and experiences.

I'm using Cherokee.
According to their benchmarks (grain of salt with them), it handles load better than both Lighttpd and nginx... But that's not why I use it.
I use it because if you type cherokee-admin, it starts a new server that you can log into (with a one-time password) and configure the whole server through a beautifully-done webmin. That's a killer feature. It has already saved me a lot of time. And it's saving my server a lot of resources!
As for django, I'm running it as a threaded SCGI process. Works well. Cherokee can keep it running too. Again, very nice feature.
The current Ubuntu repo version is very old so I'd advise you use their PPA. Good luck.

As #Barry said, the documentation uses mod_python. I haven't used Ubuntu as a server, but had a good experience with mod_wsgi on Solaris. You can find documentation for mod_wsgi and Django on the mod_wsgi site.
A quick review of your requirements:
Easy to setup I've found apache 2.2 fairly easy to build and install.
Fast and easy on resources I would say that this depends on your usage and traffic. * You may not want to server all files using Apache and use LightTPD (lighty) to server static files.
Can serve media files I assume you mean images, flash files? Apache can do this.
Multiple sites on same server Virtual server hosting on Apache.
Rather not install other extensions Comment out anything you don't want in the Apache config.

The officially recommended way to deploy a django project is to use mod_python with apache. This is described in the documentation. The main pro with this is that it is the best documented, most supported, and most common way to deploy. The con is that it probably isn't the fastest.

The best configuration is not so known I think. But here is:
Use nginx for serving requests (dynamic to app, static content directly).
Use python web server for serving dynamic content.
Two most speedy solutions for python-based web server is:
cogen
fapws2
You need to look into google to find current best configuration for django (still in development).

I’m using nginx (0.6.32 taken from Sid) with mod_wsgi. It works very well, though I can’t say whether it’s better than the alternatives because I never tried any. Nginx has memcached support built in, which can perhaps interoperate with the Django caching middleware (I don’t actually use it, instead I fill the cache manually using python-memcache and invalidate it when changes are made), so cache hits completely bypass Django (my development machine can serve about 3000 requests per second).
A caveat: nginx’ mod_wsgi highly dislikes named locations (it tries to pass them in SCRIPT_NAME), so the obvious ‘error_page 404 = #django’ will cause numerous obscure errors. I had to patch mod_wsgi source to fix that.

I'm struggling to understand all the options as well. In this blog post I found some benefits of mod_wsgi compared to mod_python explained.
Multiple low-traffic sites on a small VPS make RAM consumption the primary concern, and mod_python seems like a bad option there. Using lighttpd and FastCGI, I've managed to get the minimum memory usage of a simple Django site down to 58MiB virtual and 6.5MiB resident (after restarting and serving a single non-RAM-heavy request).
I've noticed that upgrading from Python 2.4 to 2.5 on Debian Etch increased the minimum memory footprint of the Python processes by a few percent. On the other hand, 2.5's better memory management might have a bigger opposite effect on long-running processes.

Keep it simple: Django recommends Apache and mod_wsgi (or mod_python). If serving media files is a very big part of your service, consider Amazon S3 or Rackspace CloudFiles.

There are many ways, approach to do this.For that reason, I recommend to read carefully the article related to the deployment process on DjangoAdvent.com:
Eric Florenzano - Deploying Django with FastCGI: http://djangoadvent.com/1.2/deploying-django-site-using-fastcgi/
Read too:
Mike Malone - Scaling Django
Stochastictechnologies Blog: The perfect Django Setup
Mikkel Hoegh Blog: 35 % Response-time-improvement-switching-uwsgi-nginx
Regards

In my opinion best/fastest stack is varnish-nginx-uwsgi-django.
And I'm successfully using it.

If you're using lighthttpd, you can also use FastCGI for serving Django. I'm not sure how the speed compares to mod_wsgi, but if memory serves correctly, you get a couple of the benefits that you would get with mod_wsgi that you wouldn't get with mod_python. The main one being that you can give each application its own process (which is really helpful for keeping memory of different apps separated as well as for taking advantage of multi-core computers.
Edit: Just to add in regards to your update about nginix, if memory serves correctly again, nginix uses "greenlets" to handle concurrency. This means that you may need to be a little bit more careful to make sure that one app doesn't eat up all the server's time.

We use nginx and FastCGI for all of our Django deployments. This is mostly because we usually deploy over at Slicehost, and don't want to donate all of our memory to Apache. I guess this would be our "use case".
As for the remarks about the documentation being mostly in Russian -- I've found most of the information on the English wiki to be very useful and accurate. This site has sample configurations for Django too, from which you can tweak your own nginx configuration.

I have a warning for using Cherokee. When you make changes to Django Cherokee maintains the OLD process, instead of killing it and starting a new one.
On Apache i strongly recommend this article.
http://www.djangofoo.com/17/django-mod_wsgi-deploy-exampl
Its easy to setup, easy to kill or reset after making changes.
Just type in terminal
sudo /etc/init.d/apache2 restart
and changes are seen instantly.

Related

Which python web frameworks incorporate a web sever that is suitable for production use?

I need to write a very light database (sqlite is fine) app that will initially be run locally on a clients windows PC but could, should it ever be necessary, be upgraded to work over the public interwebs without a complete rewrite.
My end user is not very technically inclined and I'd like to keep things as simple as posible. To that end I really want to avoid having to install a local webserver, however "easy" that may seem to you or I. Django specifically warns not to use it's inbuilt webserver in production so my two options seem to be...
a) Use django's built in server anyway while the app is running locally on windows and, if it ever needs to be upgraded to work over the net just stick it behind apache on a linux box somewhere in the cloud.
b) Use a framework that has a more robust built in web server from the start.
My understanding is that the only two disadvantages of django's built in server are a lack of security testing (moot if running only locally) and it's single threaded nature (not likely to be a big deal either for a low/zero concurrency single user app running locally). Am I way off base?
If so, then can I get some other "full stack" framework recommendations please - I strongly prefer python but I'm open to PHP and ruby based solutions too if there's no clear python winner. I'm probably going to have to support this app for a decade or more so I'd rather not use anything too new or esoteric unless it's from developers with some serious pedigree.
Thanks for your advice :)
Roger
I find Django's admin very easy to use for non-technical clients. In fact, that is the major consideration for my using Django as of late. Once set up properly, non-technical people can very easily update information, which can reflected on the front end immediately.
The client feels empowered.
Use Django. It's very simple for you to get started. Also, they have the best documentation. Follow the step by step app creating tutorial. Django supports all the databases that exist. Also, the built in server is very simple to use for the development and production server. I would highly recommend Django.

Apache2: mod_wsgi or mod_python, which one is better?

I am planning to write web service in python. But, I found wsgi also does the similar thing. Which one can be preferred?
Thank you
Bala
Update
I am still confused. Please help.
Better in my sense means:
1. Bug will be fixed periodically.
2. Chosen by most developers.
3. Additional features like authentication tokens like AWS, can be supported out of the box.
4. No strong dependency on version.( I see that wsgi requires python 2.6)
5. All python libraries will work out of the box.
6. Scalable in the future.
7. Future upgrade don't cause any issues.
With my limited experience, I want these features. There might be some I might be missing.
Thanks
Bala
Update
I am sorry for all the confusion caused. I just want to expose a restful web services in python language. Is there a good framework?
mod_wsgi is more actively maintained and (I hear -- haven't benchmarked them myself!) better performing than mod_python. So unless you need exclusive features of mod_python, just to use a web app framework (or non-framework, like werkzeug;-), you're probably better off with mod_wsgi! (Just about every Python web framework, and many non-frameworks of which werkzeug is my favorite, support WSGI as their standard interface to the web server, these days).
Don't confuse what WSGI and mod_wsgi are. WSGI is an interface specification for hosting Python web applications on a server. The mod_wsgi module is an implementation of the WSGI specification using Apache as the underlying web server. Thus, Python and WSGI are not choices exactly, WSGI is just one way of being able to communicate between a Python web service/application and the web server. The mod_wsgi package is one implementation of that interface. So, WSGI is a means to an end, not a solution in itself.
Personally, I'd very much suggest you just use a minimal Python framework/non framework and as Alex suggests, Werkzeug is a good choice.
If you just want to run web apps then use mod_wsgi. If you need to write a handler for the rest of httpd's request/response phases then use mod_python.
mod_wsgi is specifically tuned to run Python web apps that use WSGI in Apache. mod_python is for any kind of Python web app, including WSGI apps. mod_wsgi also has a lower memory footprint than mod_python.
mod_wsgi is much more actively maintained than mod_python at this point. It also has a good bit of momentum, as it was somewhat recently adopted as the preferred deployment method on apache2 by Django. The author is also actively engaged with the Python community in regards to the future evolution of WSGI.
Bug will be fixed periodically.
Unless you're paying money, you cannot have any idea about this.
Chosen by most developers.
mod_wsgi
Additional features like authentication tokens like AWS, can be supported out of the box.
True for every framework.
No strong dependency on version.( I see that wsgi requires python 2.6)
What? Everything depends on compatible versions. Everything. Every single piece of software.
All python libraries will work out of the box.
"All?" What about the poorly-written ones?
Scalable in the future.
Sure. We always hope for this. There's no guarantee.
Future upgrade don't cause any issues.
That's funny.
"I want these features."
We all do. Realistically, you can get #2. The rest don't make sense or cannot every be assured.

It is said best way to deploy django is using wsgi, I am wondering why?

We are deploying django application, I found in the documentation that it is recommended to use WSGI appoach for doing that.
Before deploying I wanted to know, why it is recommended over other two approaches i.e. using mod_python and fastcgi...
Thanks a lot.
wsgi is usually preferred because it decouples your choice of framework from your choice of web server: if tomorrow you want to move, say, from Apache to nginx, or whatever, the move is trivially easy with wsgi, not so easy otherwise.
Furthermore, using wsgi affords you the option to add some middleware that's framework-independent, rather than having to rely on every possible functionality you want having already been implemented and made available for your framework of choice.
We tried mod_python. It's slower and harder to configure. It doesn't offer the daemon feature.
We couldn't get fast_cgi built for our combination of Apache, Red Hat and Python. I'm not sure specifically what was wrong, but we couldn't get it built properly. It wouldn't dispatch requests to Django properly, and we couldn't diagnose the problem.
We tried mod_wsgi third. It built nicely. It has the daemon option. It's very easy to configure. It allows trivial restart of the Django applications without restarting all of Apache.
I use mod_wsgi for any production Django app. It's fast, stable, and very configurable.
You may also want to look in to the FastCGI method a bit more. Eric Florenzano just did a great write up of Django with FastCGI for the Django Advent: http://djangoadvent.com/1.2/deploying-django-site-using-fastcgi/

A production ready server to serve django on win32

I'd like to serve django application on windows XP/Vista.
The application is an at hoc web interface to a windows program so it won't be put under heavy load (around 100 requests per second).
Do you know any small servers that can be easily deployed on windows to serve a django app? (IIS is not an option as the app should work on all versions of windows)
cherrypy includes a good server. Here's how you set it up to work with django and some benchmarks.
twisted.web has wsgi support and that could be used to run your django application. Here's how you do it.
In fact any wsgi server will do. Here's one more example, this time using spawning:
$ spawn --factory=spawning.django_factory.config_factory mysite.settings
And for using paste, the info is gathered here.
Of course, you could use apache with mod_wsgi. It would be just another wsgi server. Here are the setup instructions.
If you want to give Apache a go, check out XAMPP to see if it'll work for you. You can do a lightweight (read: no installation) "installation." Of course, you'll also want to install mod_python to run Django. This post may help you set everything up. (Note: I have not used python/Django with XAMPP myself.)
Edit: Before someone points this out, XAMPP is not generally a production-ready tool. It's simply a useful way to see whether Apache will work for you. Also, I saw that you're using SQLite after the fact.
Why not Apache ?
Nokia have developed a scaled down version of apache to run on their mobile phones. It supports python.
http://research.nokia.com/research/projects/mobile-web-server/
Also do you need anything else such as database support etc?

Running Django with FastCGI or with mod_python

which would you recommend?
which is faster, reliable?
apache mod_python or nginx/lighttpd FastCGI?
I've done both, and Apache/mod_python tended to be easier to work with and more stable. But these days I've jumped over to Apache/mod_wsgi, which is everything I've ever wanted and more:
Easy management of daemon processes.
As a result, much better process isolation (running multiple sites in the same Apache config with mod_python almost always ends in trouble -- environment variables and C extensions leak across sites when you do that).
Easy code reloads (set it up right and you can just touch the .wsgi file to reload instead of restarting Apache).
More predictable resource usage. With mod_python, a given Apache child process' memory use can jump around a lot. With mod_wsgi it's pretty stable: once everything's loaded, you know that's how much memory it'll use.
lighttpd with FastCGI will be nominally faster, but really the time it takes to run your python code and any database hits it does is going to absolutely dwarf any performance benefit you get between web servers.
mod_python and apache will give you a bit more flexibility feature-wise if you want to write code outside of django that does stuff like digest auth, or any fancy HTTP header getting/setting. Perhaps you want to use other builtin features of apache such as mod_rewrite.
If memory is a concern, staying away form apache/mod_python will help a lot. Apache tends to use a lot of RAM, and the mod_python code that glues into all of the apache functionality occupies a lot of memory-space as well. Not to mention the multiprocess nature of apache tends to eat up more RAM, as each process grows to the size of it's most intensive request.
Nginx with mod_wsgi
I'm using it with nginx. not sure if it's really faster, but certainly less RAM/CPU load. Also it's easier to run several Django processes and have nginx map each URL prefix to a different socket. still not taking full advantage of nginx's memcached module, but first tests show huge speed advantage.
There's also mod_wsgi, it seems to be faster than mod_python and the daemon mode operates similar to FastCGI
Personally I've had it working with FastCGI for some time now (6 months or so) and the response times 'seem' quicker when loading a page that way vs mod___python. The critical reason for me though is that I couldn't see an obvious way to do multiple sites from the same apache / mod_python install whereas FastCGI was a relative no-brainer.
I've not conducted any particularly thorough experiments though :-)
[Edit] Speaking from experience though, setting up FastCGI can be a bit of a pain the first time around. I keep meaning to write a guide..!
I'd recommend WSGI configurations; I keep meaning to ditch apache, but there is always some legacy app on the server that seems to require it. Additionally, the WSGI app ecology is very diverse, and it allows neat tricks such as daisy-chaining WSGI "middleware" between the server and the app.
However, there are currently known issues with some apps and apache mod_wsgi, particularly some ctypes apps, so be wary if you are trying to run, say, geodjango which uses ctypes extensively. I'm currently working around those issues by going back to fastcgi myself.

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