Choosing a version of Ruby

You can choose among multiple versions of Ruby:

Ruby version Command-line path Sunset Date
2.6 /opt/rubies/ruby-2.6/bin/ruby March 31, 2022
2.7 (default) /opt/rubies/ruby-2.7/bin/ruby approx. September 30, 2023
3.0 /opt/rubies/ruby-3.0/bin/ruby approx. September 30, 2024

If you need to switch Ruby versions, you can do so by creating or editing your site's .silk.ini file (for example ~/www-root/.silk.ini) and adding the version to the [ruby] section:

version = 3.0

Valid version choices are default, any of the versions listed in the table above, or newest (which provides the newest available on the system).

Web applications

Ruby web apps are written using the Rack model and use NGINX Unit as an application server. You can run an application by doing the following:

  1. Edit the .silk.ini file in your site root. Add a section similar to the following.

    type = ruby
    root = myapp
    document-root = public
    startup-script =
    env.RAILS_ENV = production

    The .silk.ini section name should be either "app" or any descriptive name you wish for your application that starts with "app: ". This could be useful if you wish to configure multiple apps.

    root is an optional directory under your site root containing all your application files.

    document-root is the directory under your app root in which static files will be located.

    startup-script is the name of the script launching your application, which should have executable permissions (chmod u+x

    Any line beginning with env. will set an environment variable available within your application.

  2. If this is the first web application in your site, a new app server will be started for your account within ten minutes.

  3. Load your application with silk app <hostname> load. If you have multiple sites and/or multiple apps, <hostname> is followed by the URI path of your app, such as If you see an error, check the app server log for details.

Reloading applications

An application needs to be restarted for code changes to take effect. You can do this the same way you originally loaded your application:

[myusername@silk21 ~]$ silk app <hostname> load

Console logs

App server logs are available at /usr/lib/unit-user-<mynetid>/unit.log.


Ruby libraries are managed using the gem command.

You can see which libraries are currently installed by typing gem list.

Additional modules can be installed by typing gem install --user-install <libraryname>, which will place them in your home directory, under ~/.gem/.