How To Install Ruby on Rails on an Debian 7.0 (Wheezy) VPS using RVM

We will be installing RVM from the project’s website, so we will not be relying on Debian’s default repositories for the actual installation.

However, RVM uses the package manager to install dependencies for the programs it manages, so we should make sure those repositories are up-to-date:

sudo apt-get update

Next, we will install RVM, Ruby, and Rails in a single command. This assumes that you want a single-user installation, which will be applicable in most cases. Do this as a regular user, not as root:

\curl -L https://get.rvm.io | bash -s stable --rails

This will take awhile to finish. When complete, you will have a stable Ruby instance and the Rails framework installed.

Once the process is complete, we need to make our environment aware of the new RVM installation. This will happen automatically when we open new terminal windows from now on:

source ~/.rvm/scripts/rvm

You can easily get info from RVM about what Ruby version is being used currently and what the file paths are for related applications and services.

Run the info command to get these details:

rvm info

ruby-2.0.0-p247:

  system:
    uname:       "Linux RVM 3.2.0-4-amd64 #1 SMP Debian 3.2.41-2+deb7u2 x86_64 GNU/Linux"
    system:      "debian/7/x86_64"
    bash:        "/bin/bash => GNU bash, version 4.2.37(1)-release (x86_64-pc-linux-gnu)"
    zsh:         " => not installed"
    . . .

We can find info about the current and available Ruby versions installed by issuing the command:

rvm list

rvm rubies

=* ruby-2.0.0-p247 [ x86_64 ]

# => - current
# =* - current && default
#  * - default

To find other Ruby versions that are available for installation, type:

rvm list known

# MRI Rubies
[ruby-]1.8.6[-p420]
[ruby-]1.8.7[-p374]
[ruby-]1.9.1[-p431]
[ruby-]1.9.2[-p320]
[ruby-]1.9.3[-p448]
[ruby-]2.0.0-p195
[ruby-]2.0.0[-p247]
. . .

You can then install the desired Ruby by typing:

<pre> rvm install <span class=“highlight”>version_of_ruby</span> </pre>

To switch over to a different Ruby, type:

<pre> rvm use <span class=“highlight”>version_of_ruby</span> </pre>

You can test that Rails is installed correctly by creating a sample app, which will live in your home directory.

This will create an application called sample:

cd ~
rails new sample

We need to enter the app directory in order to have the correct environment for launching the Rails development server:

cd sample

You can try to start the server now, but it will not execute correctly:

rails s

/home/demo/.rvm/gems/ruby-2.0.0-p247/gems/execjs-2.0.2/lib/execjs/runtimes.rb:51:in `autodetect': Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes. (ExecJS::RuntimeUnavailable)
	from /home/demo/.rvm/gems/ruby-2.0.0-p247/gems/execjs-2.0.2/lib/execjs.rb:5:in `<module:ExecJS>'

Rails isn’t finding an appropriate JavaScript executable. We will install two gems (Ruby packages) that will provide the necessary dependencies, into our application environment.

Edit the Gemfile file, which contains the specifications of what the application requires:

nano Gemfile

Add the following two lines at the end:

gem 'execjs'
gem 'therubyracer'

Save and close the file.

Now, we will run the command that will ensure that all of those dependencies are installed:

bundle install

Finally, we can run the Rails development server to take a look at our app:

rails s

Point your browser to your server’s IP address, followed by “:3000”:

<pre> <span class=“highlight”>your_IP_or_domain</span>:3000 </pre>

You should see the default Rails page:

<img style=“border:2px solid black; display:block;margin-left:auto;margin-right:auto” src=“https://assets.digitalocean.com/articles/rvm_debian/rails_page.png” alt =“RVM Rails default page” />

This means you’re well on your way to deploying your app or website. Congratulations, you have Ruby on Rails installed!

Although there are several ways to install Ruby and Rails on Debian, this is probably the most preferred method, due to its flexibility and its insistence on keeping application environments separated.

RVM has many additional features that can provide structure and control over your development environment. The project’s site provides great documentation on how to best utilize this powerful tool.

<div class=“author”>By Justin Ellingwood</div>