Based on articles at http://articles.slicehost.com/centos
This gist only covers the steps that are necessary to get a Rails app running quickly via RVM, nginx and Passenger. It disregards security in many cases (such as RVM & iptables)! Go through the articles above for more on that.
Please note that I wrote this after I had already got it all working, so I apologize if
there is anything missing. If you get a permission error from the OS, I may have left
off a sudo, so try running the command with that. Please comment if you have any issues,
if I left something out, or if you can recommend any improvements.
These commands were used on a fresh rebuild of CentOS release 6.2 (Final) on a Rackspace
server.
If you don't need the explanations, see below for a tl;dr.
SSH in as root and immediately change the password:
ssh root@x.x.x.x
passwd
Allow users of wheel group to issue all commands:
/usr/sbin/visudo
Uncomment (near bottom of file):
%wheel ALL=(ALL) ALL
Make sure not to uncomment the one with NOPASSWD
Add a user & add to wheel group:
/usr/sbin/adduser edward
passwd edward
/usr/sbin/usermod -a -G wheel edward
Recommended, but not necessary to get the Rails app running. This provides added security and also keeps you (or any user with properly installed keys) from having to type in a password on every login. Read this article for how to set up SSH keys.
Flush IP tables so nginx can connect to port 80 (default for HTTP connections):
/sbin/iptables -F
For a production server, iptables should be configured securely. See this article for how to do that.
Logout & login as the newly created user:
exit
ssh edward@x.x.x.x
Yum is a package management system that uses RPM. Yum is to RPM what Bundler is to RubyGems, and in fact its commands are very similar to Bundler's. For example, you can run this to update any installed packages to the latest possible versions:
sudo yum update
To make sure you already have Yum, simply run:
yum -h
If your build of CentOS didn't already have Yum installed (most will already have it),
then you can use rpm to install it. Start with this article.
Not necessary, but it's a good idea to have these installed, which provide a larger amount of packages, as well as more current versions of each. Read this article for how to set it up (it's easy and quick).
RVM is the "Ruby Version Manager", and makes it easy to upgrade and downgrade Ruby, as well as maintain gemsets for different users or applications.
There are two options: Install RVM user-by-user, or install it globally. I will show how to install it globally here (for faster setup), but RVM recommends the first option because installing globally can be a security risk.
Install RVM globally:
curl -L https://get.rvm.io | bash -s stable --rails
Install dependencies (as listed by RVM after you run the command above):
sudo yum install -y gcc-c++ git patch readline readline-devel zlib zlib-devel libyaml-devel libffi-devel openssl-devel make bzip2 autoconf automake libtool bison iconv-devel
Add users to the rvm group created by rvm, and load the RVM script:
su root
/usr/sbin/usermod -a -G rvm edward
source /etc/profile.d/rvm.sh
exit
Logout and log back in to make sure RVM takes effect:
exit
ssh edward@x.x.x.x
Install Ruby & set as default:
rvm install 1.9.3
rvm use 1.9.3 --default
RVM Installs RubyGems (i.e. the gem cli) for you.
Run this command to make sure it's at the latest version:
gem update --system
SQLite3 is the database that Rails applications use by default. To install the package and its dependencies, run:
sudo yum install sqlite-devel
Optionally, you can install the sqlite3 gem at the system level, but your application's
Gemfile will tell Bundler to install it by default. It might be a good idea to run
gem install sqlite3 now, though, just to make sure the SQLite3 library is properly
installed on the system.
If you need or want to use MySQL instead of SQLite, start with this article for how to install and configure.
Passenger runs Rack applications (like Rails), and nginx proxies HTTP requests. We're going to use them over the alternatives because together they are easy and quick to setup, powerful, and production-ready.
First, install curl-devel, as the installer requires it:
sudo yum install curl-devel
Passenger will install nginx, so no need to do it via yum.
Install the gem and run the installer:
gem install passenger
rvmsudo passenger-install-nginx-module
Follow the instructions. Notes:
- Use Option 1 (allowing the installer to download & compile Nginx itself) for quicker setup
- When prompted for Nginx prefix directory, you can just hit
[Return], and it will be installed to/opt/nginx. - If there are any missing dependencies at this point, the installer will very clearly explain what to do. It's fail-safe and idiot-proof! Perfect for me and you.
Rerun rvmsudo passenger-install-nginx-module if necessary after installing dependencies
This step isn't totally necessary but I'm putting it in here because it's quick and easy and will help you in working working with nginx.
Installing nginx via Yum (which we didn't do) does this automatically, so we have it do it ourselves:
vi /etc/init.d/nginx
Copy and paste the script in the file below.
Be sure to modify the paths to nginx if you didn't use the /opt/nginx default!
Make it executable:
sudo chmod +x /etc/init.d/nginx
Add nginx to server startup commands:
sudo /sbin/chkconfig nginx on
First, add a user, www-data, which will be used by nginx & Passenger
(based on the nginx config file, below):
su root
/usr/sbin/adduser www-data
exit
Edit the nginx config file:
sudo vi /opt/nginx/conf/nginx.conf
The passenger installer will create this file with a bunch of useful stuff in it
(as long as you didn't already have an nginx.conf in the same place). We just
need to change and add a few things to get it setup for Rails on our server.
First, change # user nobody; to:
user www-data;
Then, inside of the http directive (which Passenger adds by default),
define your server:
http { # You only need one of these in the nginx config file
server {
listen 80;
server_name yourdomain.com; # Or the server's IP if you don't have a domain yet
root /web/rails/demo_app/public; # `demo_app` is the root of your rails app
passenger_enabled on;
rails_env development;
}
}
A couple things to note:
-
Although we haven't created a Rails app yet, put where you think it will be in the
rootdirective. Of course, you can always come back and change that path after you've setup the Rails application. After you change the path, reload the config with/etc/init.d/nginx reload. -
I have the
rails_envoption set todevelopmentjust so we can get the Rails app running as quickly as possible. In the production environment (with the default Rails production config), we would have to worry about precompiling assets, the classes and views would all be cached (which would require us to restart Passenger every time we made a change), and the error messages would be "User-Friendly" (i.e. "Useless"). You'll need to deal with all of these things at some point, and change therails_envoption in your nginx config toproduction, but for now let's just get something working!
Restart nginx:
/etc/init.d/nginx restart
Apache is an HTTP proxy (an alternative to nginx), and can be installed with Passenger similarly to how it is done with nginx. Start with this article if you decide to use Apache instead of nginx.
Thin and Unicorn are HTTP servers for Rack applications (alternatives to Passenger). Each one has advantages and disadvantages, which you can research yourself. If you decide to use something besides the nginx + Passenger method described in this gist, browse through this list of articles to find a combination of Thin, Passenger, Apache, and Nginx that suits your needs.
For Unicorn + nginx, read this article.
You might also consider Mongrel2, new but promising.
Install Node for JS runtime. This is an alternative to adding execjs and therubyracer
to your app's Gemfile. I prefer this method because all of your applications will need it,
and Node.js is very cool and useful for many purposes.
Plus, this will also install npm which is very useful:
cd /tmp/
wget http://nodejs.tchol.org/repocfg/el/nodejs-stable-release.noarch.rpm
sudo yum localinstall --nogpgcheck nodejs-stable-release.noarch.rpm
sudo yum install nodejs-compat-symlinks npm
gem install rails
mkdir -p /web/rails
cd /web/rails/
rails new demo_app
Give user www-data owner permissions for anything already under /web:
chown -R www-data /web
I don't recommend using Rails' scaffold generator (you don't learn anything except how
to run the scaffold command), but for our purposes, to get a quick demo app up and running
(what scaffold is really meant for), let's do it!
cd demo_app
rails g scaffold post title:string body:text
Create and migrate the database:
rake db:create
rake db:migrate
Edit your routes.rb file:
vi config/routes.rb
And add (right below resource :posts, which scaffold added automagically):
root to: "posts#index"Restart Passenger (Might not be necessary but it doesn't hurt):
touch tmp/restart.txt
Now visit your website! If you don't have a domain or you haven't setup the DNS for it, you can just visit the IP address of your server (from your browser).