I recently had to roll a new VM for work in order to run Rails and Sinatra apps on Apache/Passenger. My company favors CentOS as the default distro for all our boxes, so I wasn’t able to use all the super-up-to-date packages that Ubuntu makes available, and I ended up building everything from source. For posterity and for anyone else who needs it, here’s a list of what to do and how to do it.

Dependencies

You’ll need several libraries and the MySQL server, and you can use yum to install them all at once. This set includes the gcc compiler, the gcc-c++ compiler, and the zlib development headers for Ruby. Remember: not all libraries are the same — you’re going to need to make sure that you’re compiling Ruby w/ 32 or 64-bit development headers as appropriate for your architecture.

Ruby

Next up is Ruby. We’ll install 1.8.7-p72, the latest stable as of this writing. First, we’ll make a “src” directory in /usr/local to hold everything:

Ok now for a weird thing — you need to remake and re-install Ruby after using it to run a script that helps you make a new makefile. This is so that you can tell it where the zlib headers live:

After all that happens, you should have Ruby installed. Check and see by doing:

You should see something like:

Rubygems

Now that you have Ruby installed, Rubygems is easy — the whole thing is in Ruby so there’s nothing to build/compile.

Rails, Passenger, MySQL and Sinatra

Now that Ruby and Rubygems are installed, you can install Rails, Passenger, and Sinatra as gems:

That will take awhile, as there’s a ton of documentation to build for Rails, and Passenger has to compile some native extensions.

Once that’s done, finish the Passenger installation with their nifty installer tool:

Follow the provided instructions at the end of the installer for adding lines to httpd.conf:

After that, install the MySQL gem, making sure to specify where the config is:

Disabling SELinux

The RedHat family of distros (RHEL, CentOS, Fedora) come with SELinux enabled by default. If you want to learn how to make it work with Passenger, you can try this tip from the Passenger user’s guide. I just turned it off because the box is only going to be used for these apps, and SELinux seems like overkill. Here’s how to shut it down:

First, disable it temporarily:

That’s not a permanent fix though, because the next time the server boots, it’ll be turned back on again. You need to edit the config file and turn it off. Open it with your favorite editor and change one line. You need to be root or running as sudo to edit this file, and I prefer Vim when on remote servers, so it’s:

Change this:

to this:

Restart Apache

You should be able to restart Apache now and have Passenger come up no problem. There are several ways to restart Apache, but I like to use the service way to keep it simple:

Optional: Installing Git

For SCM, there are a lot of reasons why I like Git better than Subversion. It’s got a bit of a learning curve, but once you go Git, you never go back.

And the man pages:

Now you should have Git installed and ready. Prove it:

You should see something like:

And that’s it — you now have a full Ruby stack ready to go on CentOS 5. Much of this tutorial was adapted from the awesome Hivelogic post on installing the stack on OS X Leopard.