First of all please let me be clear that I am a windows user and very new to the web world. For the past months I have been learning both python and django, and it has been a great experience for me. Now I have somehow created a small project that I would like to deploy in the production server. Since django has its built-in development server there was no problem for me. But now that I have to deploy it to a production server I googled around and found Nginx + uWSGI or Nginx + Gunicorn as the best option for it. And as uWSGI and Gunicord are incompatible with Windows, I think I should adapt Ubuntu or other Unix system.
So my questions are:
Just to be clear, as I will have to work with one of the above, please explain to me why do I need two servers?
If I have to adapt the Ubuntu environment, do I have to learn Ubuntu shell scripting, SSH and other stuff? Or the hosting provider will help me do that?
Please let me be aware of what else do I need for the above concerned.
Thank you so much for your time and please pardon if my question was a lame question. Hoping for positive response answers.
A typical configuration involves two server processes (which can be run together on the same actual hardware or virtual server) so that the proxy server in front can buffer slow clients. For instance: a slow client will connect to nginx with a request. Nginx will pass the request on to Gunicorn and Gunicorn will respond. Nginx will then consume the Gunicorn response immediately, freeing up the Gunicorn resources right away. At that point, the slow client can take as much time as it wants to consume the response from Nginx without tying up much in the way of server resources. Alternatives to the two-server-process model are to use async workers with Gunicorn and put Gunicorn itself in front, or to use an async-sync combo like Waitress. Nginx in front has the added benefit of doubling as a ready-to-use statics server, though.
Note that "slow clients" can describe: mobile phones that lose their connection and leave the TCP socket hanging until timeout mid-request; mobile phones that are just slow; unreliable connections of all types; hostile denial-of-service clients who are deliberately trying to use server resources; sometimes any old connection that has a hiccup or malfunction for any reason. So this is a problem that will affect nearly any site.
You won't need shell scripting per se but getting used to Ubuntu will take some time. There is a lot to learn even outside of scripting, like how to use the package manager, how to configure packages once they're installed in ways that won't confound future updates, etc. And you will definitely have to learn to use SSH; it is one of the most fundamental server administration tools in the *nix world.
An alternative to learning to use Ubuntu or another server platform is to use a Platform-as-a-Service option like Heroku, as PaaS hosting providers really will take care of all of that stuff for you. I recommend this approach. That having been said, even though I think PaaS is a good option for people who want to focus on development and not server admin regardless of their level of skill, it's also true that a little bit of experience with Linux server platforms goes a long way in helping you to understand the environment that your code runs in. So even if you go with PaaS, you would still benefit from tinkering with Ubuntu a little (or a lot).
Another benefit from a PaaS is that normally their infrastructure handles the Nginx part of the deal (buffering of slow requests via proxy). This is the case with Heroku, for instance. So you won't have to worry about that part of the infrastructure at all.
This part of the question is too broad to answer, but let me know in the comments if you need clarification.
I'm doing it almoast like in this tutorial: http://michal.karzynski.pl/blog/2013/06/09/django-nginx-gunicorn-virtualenv-supervisor/
Nginx is my proxy to django app running on gunicorn and its serving statics, virtualenv for my python enviroment, supervisor to watch my app's running.
It's possible you will run in some error's if not using Postgresql, ask then I will help (used MySQL in the past now it's Postgresql)
Firstly, there's no need to use Ubuntu if you're happier with Windows. I don't know if nginx works on Windows, but I'd be very surprised if it doesn't (in fact, here are the nginx docs for installing on Windows). Apache, meanwhile, definitely does work on Windows. The Django documentation has a full explanation of how to set up Apache/mod_wsgi to serve Django.
You don't need two servers. I'm not sure why you think you do: the usual reason for that is to have the static assets on a separate server, but you don't mention that as a reason. Since you're only talking about a small site, though, you don't even need to do that. One server configured to serve both Django and the static assets will do fine. Again, the docs explain exactly how to do that.
Related
Is there good alternatives to the django developement server (runserver) that are more performant,
especially in concurency and static serving, and that have the auto-reload function, without having to setup a full blown production environment ?
Im working on Windows so gunicorn cannot be used.
You can install and use the rungevent commant. It has auto-reload function and it's more performant than thread-based servers (it is greenlet-oriented). The only caveat is the static file serving: you must install a webserver or proxy like nginx for that.
Are you doing so high bulk tests in ur dev server so you suffer this -specially regarding static files-? If so, then you must emulate, as said, a productive environment (just have an nginx correctly configured pointing to the address:port you use for your rungevent command).
If static files is not your problem, install a rungevent command and try how it works.
No since dev sites are made to handle limited requests, runserver runs fine on a machine that can match the requirements of your app.
If you are dealing with a large scale dev project which your system cannot tolerate, then it's either time to reproduce a production environment or upgrade.
I find it difficult to believe that your application is that bad in terms of performance, again if you are trying to test the behavior of a full production site (in terms of DB entries etc) then its time to emulate the production environment.
If that is not the case, then I would start checking the underlying models / code of the project.
Well, if you don't want to use django dev server you will have to spend some time to setup anyway. But the good part is that you can do it only once. Sequential deploying will take very little time.
Not so much time ago I switched from fastcgi to uWSGI and it made my life much easier.
uWSGI is awesome! It has autoreload (which works both in daemon mode and when launched directly in terminal). When launched in terminal you can use debugger (e.g. pdb) during request just like you do in django dev-server. And of course you can debug with print in simple cases.
I'm using it with nginx which serves both static and uWSGI but it of course can be any server.
The most useful feature for me in this configuration is that you use the same thing both for dev and production. For simple projects after developing you just turn off autoreload and a few other options and it's ready.
If you were deploying a production rails 4/ruby 2 app on unix, what app/web server would you use and why?
I have been using apache/passenger for my rails 2 & 3 apps for years, no big problems, it generally works pretty well. We have had one app that kept restarting and leaked memory, but most have been fine.
This app may have a bit more bursty traffic and require a bit more concurrent usage.
Other options I have read about :
Thin,
Unicorn,
Puma
I do need to support HTTPS, but don't need to run any other apps on this server, so I don't need all the features of Apache.
So I would like to hear from folks that run production apps in think, unicorn, puma or others, or even the latest passenger (with apache or nginx) and see if they have opinion on reliability, security & performance of these servers.
I found this today, I think it does a pretty good job at articulating the pros/cons of the options I described above - https://www.engineyard.com/articles/rails-server
The documentation states that one should not server static files on the same machine as as the Django project, because static content will kick the Django application out of memory. Does this problem also come from having multiple Django projects on one server ? Should I combine all my Website-Projects into one very large Django project ?
I'm currently serving Django along with php scripts from Apache with mod WSGI. Does this also cause a loss of efficiency ?
Or is the warning just meant for static content, because the problem arises when serving hundreds of files, while serving 20-30 different PHP / Django projects is ok ?
I would say that this setup is completely ok. Off course it depends on the hardware, load and the other projects. But here you can just try and monitor the usage/performance.
The suggestion to use different server(s) for static files makes sense, as it is more efficient for the ressources. But as long as one server performs good enough i don't see a reason to use a second one.
Another question - which has less to do with performance than with ease of use/configuration - is the decision if you really want to run everything on the same server.
For one setup with a bunch of smaller sites (and as well some php-legacy) we use one machine with four virtual servers:
webhead running nginx (and varnish)
database
simple apache2/php server
django server using gunicorn + supervisord
nginx handles all the sites, either proxying to the application-server or serving static content (via nas). I like this setup, as it is very easy to install and handle, as well it makes it simple to scale out one piece if needed. Bu
If the documentation says """one should not server static files on the same machine as as the Django project, because static content will kick the Django application out of memory""" then the documentation is very misleading and arguably plain wrong.
The one suggestion I would make if using PHP on same system is that you ensure you are using mod_wsgi daemon mode for running the Python web application and even one daemon process per Python web application.
Do not run the Python web application in embedded mode because that means you are running stuff in same process as mod_php and because PHP including extensions is not really multithread safe that means you have to be running prefork MPM. Running Python web applications embedded in Apache when running prefork MPM is a bad idea unless you know very well how to set up Apache properly for it. Don't set up Apache right and you get issues like as described in:
http://blog.dscpl.com.au/2009/03/load-spikes-and-excessive-memory-usage.html
The short of it is that Apache configuration for PHP and Python need to be quite different. You can get around that though by using mod_wsgi daemon mode for the Python web application.
I know that it's bad to use the Django web server in production. There's been at least one Stackoveflow question on this already.
But I'm wondering about where to draw the line between development and production? If I'm only allowing HTTP access to one (or a few) IP addresses, then I know I'm in development. What if I open it to all IP addresses, but only e-mail a couple friends to see what they think of what I've built?
As far as I can tell, the problems with using the Django server are:
It's single-threaded
Security
I don't think (1) is likely to be an issue if I'm only sharing it with a few people. For (2)--what's the worst-case scenario? Does it make a difference that I'm running on an Amazon EC2 server that I could very easily restart from a backup if something bad happened?
Well, the answer is very simple actually, you've left development when you have something you must protect: real user personal information, real data in your database that you'd be afraid to lose, etc.
Security isn't a concern until these things are present. The rule about not using the dev server in "production" is guidance, not mandatory. You can fire up the dev server in your production environment any time you want. However, you'd be silly to do so and then open up universal access to it, once your site is truly live and in use by the world.
Setting up mod_wsgi (or some other WSGI container) on a development machine takes all of 5 minutes, and can help you sort out deployment issues before you actually reach deployment. So really, why ever use the development server if you don't have to?
We're making a product which requires a web service to hook up to an existing database used by one of our other products. Owing to time constraints we need to get this thing up and running pretty quickly. Our web server is Apache on a Linux machine, and the client software for the new product is constrained to communication on Port 80. Our dilemma is that we can't just get a new server in time (Apache can't share port 80) and so the plan is to route requests through the existing Apache server.
I know we can hook Apache up to Tomcat using mod_jk, but what I want to do is overlay Apache Axis on Tomcat to make use of SOAP. I'm currently downloading everything I need to test this out, but not having used Axis before, I'm just curious as to whether anybody has actually tried this before and if so, does it / can it work? If there are going to be any roadblocks stopping me from doing this then a heads-up would be much appreciated.
I can't seem to find anything which says this particular setup will or won't work, apart from a posting on the Ubuntu forums which looks similar to what I'm attempting to do but on closer inspection appears to be different.
So to summarise, what I'm curious about is whether accessing a SOAP Web Service through Apache web server, connected to an Axis / Tomcat combo would work?
I'm assuming for now that with a little jiggery-pokery it should be ok, but I'll admit I'm in unfamiliar territory here so any advice / information would be a big help.
Thanks,
Tom
Having just installed and configured all of the necessary components, it appears that this does work. I'm yet to test whether it allows a web service to work from a client machine properly yet, but all signs look good so far!
I worked on a product that had exactly this setup about a year ago. I'm afraid the details are a bit fuzzy, but I don't remember having any problems with the software stack. If you find you need help, comment back here and I'll try to dig up some more info.