I am on the starting level of rails development. Recently i have been studying about web servers like puma, unicorn, webrick.
On the production level we need apache or nginx to handle the load balancing and processing the requests, my question is on my development machine i have no apache or nginx installed but how my rails project is working.
Thanks
Apache / Nginx serves a static files: css, js, html pages and etc.
They do it very good, and thus they're used for the production servers with high-load file traffic.
For self purpose we are need not much, thus we are satisfied with basic tools for development, such as embedded "file server" in webric or puma or unicorn.
Not make sure that I'm right, it's a kind of magic, probably somebody has more information?
I have a web server serving multiple Rails applications using a combination of nginx and Passenger. This is pretty straightforward, because the Passenger install sets-up pretty much everything you need to connect to nginx.
I found "Rails app with Puma" that seems to explain how to set up nginx and Puma together. How would this configuration need to be modified in order to serve a second Rails application on the same server?
Also, this guide doesn't say anything about restarting the application automatically if there is a system reboot or some other issue. Is there a way to do that? The nginx + Passenger combo seems to do it by default.
This question already has an answer here:
Is it necessary to put Unicorn behind Nginx ( or Apache)
(1 answer)
Closed 8 years ago.
I've been reading up on rails deployment and it seems for the two options I'm considering, unicorn and passenger, the tutorials always put them behind a server like nginx. I was under the assumption that both unicorn and passenger were fully functioning web servers themselves. So
Why are they always placed behind something like nginx?
If I use a load balancer nginx or HAProxy, can I have the load balancer directly distribute requests to unicorn or passenger, or do I still have to place them behind nginx?
Unicorn must be placed behind Nginx, by its author's design. The Phusion Passenger Design & Architecture document explains why some app servers are designed to be placed behind Nginx. Basically, it has got to do with I/O concurrency handling and I/O security.
Phusion Passenger however does not need to be placed behind Nginx. Phusion Passenger integrates into Nginx, as an Nginx module. Even the Standalone mode of Phusion Passenger does not need to be placed behind Nginx, because its Standalone mode utilizes a lightweight Nginx core and thus already properly implements I/O security.
If you use HAProxy, you can have it directly connect to Unicorn as long as you configure HAProxy to perform both request and response buffering. For Unicorn, buffering is key. Phusion Passenger on the other hand doesn't care, it works fine regardless of whether you configure buffering or not.
My head is about to explode from the mangled mess as a result of the following few days trying to setup a development environment for Rails, Apache and Passenger.
The questions I have are:
Do you NEED passenger for a development environment? Can I just develop with pow.cx instead? - I am 99.99% sure the answer is no (you don't use passenger for development), but I need confirmation since I am deeply confused now.
When I deploy, I only use Passenger for that, correct? I.e. I don't ever touch passenger until I deploy.
Is my development environment correct?
Production deployment is simply moving a rails application under the effects of Passenger coupled with an Apache VHOST?
Background (I suggest you read):
It seems that all the information on the web is concerned about explaining things for people who already know what they are doing, rather than explaining in detail how things work it's just a series of installation steps and that has left me extremely confused on the role of things, and how to setup a development environment and deploy a RoR application correctly - so please bear with this long question.
For the past 3 days I have been trying to setup a development environment on my Macbook Pro that isn't destroyed by Apple's rediculous limits on Apache installations. I installed a custom Apache install (from bitnami using their ruby stack, since I refuse to use Server.app) so that I can run Apache and upgrade things like PHP to 5.5 easily, and that works fine.
I am trying to get into RoR but so far it has been a struggle, and I am about ready to give up.
I understand you need Apache to serve Rails applications so that the server can handle requests concurrently rather than one at a time, and that various interfaces for this exist like Thin or whatever; Passenger was highly recommended.
I installed Passenger via their instructions and did some hackery to compile it for the Bitnami passenger installation, rather than the default Apache on Mac OS X - and it's working. When I start apache and run: passenger-memory-stats I get results expected from the installation guide, so that tells me passenger is running.
However, when I try and deploy a simple hello world Rails application I get a slew of "We're sorry…" or no result at all and just a blank page.
I am fairly sure my development environment is correct, everything works except this last bit. I can picture development taking place on a pow.cx server, and once deployment is ready you simply copy the Rails application and configure Apache's VHOST to point to your ready-to-deploy app while Passenger handles the rest, is that correct?
I am using PostgresSQL via the Postgress.app, the server works fine and I can connect to it.
I have gem 'pg' in my Gemfile.
I have already read, and tried every conceivable solution from the following SO questions, but I either get no result or empty logs which is… infuriating to say the least:
We're sorry, but something went wrong. - with Rails, Apache, Passenger
Ruby on Rails: How can i edit database.yml for postgresql?
How do I set up the database.yml file in Rails?
https://www.ruby-forum.com/topic/187128
So with all that said, I am trying to deploy this hello world application (which works on a standard rails server) using the following:
INVOKING APPLICATION VIA:
http://dmarket.local:8081/
VHOSTS:
<VirtualHost *:8081>
PassengerEnabled on
RailsEnv production
ErrorLog /Applications/rubystack/apache2/htdocs/helloworld/project_error.log
CustomLog /Applications/rubystack/apache2/htdocs/helloworld/project_error.log combined
ServerName dmarket.local:8081
ServerAlias www.dmarket.local:8081
DocumentRoot "/Applications/rubystack/apache2/htdocs/helloworld/public"
PassengerPreStart http://dmarket.local:8081
<Directory "/Applications/rubystack/apache2/htdocs/helloworld/public">
Allow from all
Options -MultiViews
</Directory>
</VirtualHost>
HOSTS FILE:
127.0.0.1 dmarket.local
127.0.0.1 www.dmarket.local
DATABASE.YML (same for development, test, and production):
adapter: postgresql
encoding: unicode
host: 127.0.0.1
port: 5432
database: tsujp
pool: 5
username: tsujp
password:
A summary of answers to your questions
You don't need Passenger in development. You can develop with Pow, and deploy with Passenger.
But you can use Passenger in development if you want to. It is a good idea to use Passenger in development because that way your development environment will match your production environment more, which reduces the risk of running into unexpected problems when you deploy.
Using Passenger in development is very easy. Use it's Standalone mode, and run passenger start instead of rails server.
Pow is strictly a development-only server. The authors recommend against using it in production.
When you deploy, you touch Passenger. You don't have to touch Passenger until deployment time, but you may.
Production deployment is indeed moving an application under the effects of Passenger, and setting up a virtual host. You will of course also need to install gems (bundle install) setup the database (editing config/database.yml), running database migrations (bundle exec rake db:migrate), etc.
I've also posted updates on the posts that you linked to, in order to make life easier for people who happened to have found those posts via search.
Apache vs Nginx
You will find a lot of people recommending Nginx (e.g. Sergio just did). I second that recommendation. Nginx is faster than Apache, handles slow clients better and is generally easier to use.
Passenger works great with Nginx. It has an Nginx integration mode that is just as easy as the Apache mode. Sergio suggested Nginx + Unicorn or Nginx + Puma, but Nginx + Passenger (which replaces Unicorn/Puma) is much easier to setup, performs great, uses less memory, works better and has more features. Nginx + Unicorn requires a lot of configuration, process management using init scripts, etc.
But this is just a recommendation. You don't have to use Nginx. Sticking with Apache + Passenger is fine. Apache works well enough for most people.
Regarding your Passenger problems
However, when I try and deploy a simple hello world Rails application I get a slew of "We're sorry…" or no result at all and just a blank page.
Whenever you get an unexpected error, the first thing you should do is to read the log files. There are two log files that are important to you:
The web server error log, typically /var/log/apache/error.log. This log file contains:
Phusion Passenger error messages.
Everything that the Rails application writes to STDERR. This typically consists of errors that Rails encounters during startup (but not errors that it encounters when it's handling requests).
The Rails development log (or production log, in case you're running in production), log/development.log (or log/production.log). When an error occurs during request handling, it is typically logged here. This file does not contain errors that Rails encounters during startup.
The error messages will often tell you what the problem is and how to solve it.
This tip can also be found in the Phusion Passenger manual, Troubleshooting section.
Capistrano
Sergio recommended Capistrano. I second that recommendation. You should remember that Capistrano complements Passenger; it does not replace Passenger. Capistrano is a tool for automating tasks. Do you currently create a tarball of your app and scp it to your server, and extract it there? Well, Capistrano automates this sort of thing for you.
For more information about how all the different pieces of the stack fit together (Apache, Passenger, Capistrano, HAProxy, Chef, etc), check out the section "The big picture" on the Phusion Passenger documentation page.
Recommendation summary
Use passenger start in development. It is by far the easiest to get started with. You don't have to edit any configuration files, it works immediately.
Use Phusion Passenger for Nginx in production.
You don't need Passenger in development. In fact, in development mode you don't need even apache. You can use built-in Webrick server ($ rails server) to run your app. And yes. Pow is a good tool, I use it all the time.
In production there are also multiple options. One of them is Apache+Passenger, yes. But you need to put Nginx in front of those (because Apache doesn't handle slow clients very well). If you have nginx, then you can replace apache+passenger with something else. For a long time I've been using Unicorn (ruby web server from github). Now my current favourite is Puma. It uses less resources than unicorn, but has more requirements to your code (it better be thread-safe, because puma is a threaded server).
Now, to the development-production discrepancy: it is known that development should resemble production as closely as possible, because it minimizes risks when deploying. So, my suggestion is: use unicorn everywhere (both development and production). Only on production put nginx in front of it.
Also,
for actually performing deploys, look into Capistrano. It became industry standard for deploying rails apps (but it can also deploy PHP, static files and what have you).
We have a RedHat box with Apache2, PHP5 and MySQL 5 for much of our development. Now, we have a Rails client, and we need to set up a Rails app on the same server. Can we install Ruby and the Rails framework with the same Apache, or should we avoid this? Why or Why not? Is it possible to direct subdomains to either PHP or Ruby in the individual V-host definitions?
Yes, you can configure your virtual hosts to Rails, PHP, or anything else with the proper configuration. The details depend largely on how you are connecting to Rails, but generally however you would configure a single purpose Apache server should work for the virtual hosts.
Yeah - Install passenger, then you can configure your sites through your apache conf files. The passenger docs contain everything you'll need to know!