Using the Elastic Beanstalk Ruby platform - AWS Elastic Beanstalk

Using the Elastic Beanstalk Ruby platform

The AWS Elastic Beanstalk Ruby platform is a set of environment configurations for Ruby web applications that can run behind an NGNIX proxy server under a Puma application server. Each platform branch corresponds to a version of Ruby. If you use RubyGems, you can include a Gemfile file in your source bundle to install packages during deployment.

Application server configuration

Elastic Beanstalk installs the Puma application server based on the Ruby platform branch that you choose when you create your environment. For more information about the components provided with the Ruby platform versions, see Supported Platforms in the AWS Elastic Beanstalk Platforms guide.

You can configure your application with your own provided Puma server. This provides the option to use a version of Puma other than the one pre-installed with the Ruby platform branch. You can also configure your application to use a different application server, such as Passenger. To do so, you must include and customize a Gemfile in your deployment. You're also required to configure a Procfile to start the application server. For more information see Configuring the application process with a Procfile.

Other configuration options

Elastic Beanstalk provides configuration options that you can use to customize the software that runs on the Amazon Elastic Compute Cloud (Amazon EC2) instances in your Elastic Beanstalk environment. You can configure environment variables needed by your application, enable log rotation to Amazon S3, and map folders in your application source that contain static files to paths served by the proxy server. The platform also predefines some common environment variables related to Rails and Rack for ease of discovery and use.

Configuration options are available in the Elastic Beanstalk console for modifying the configuration of a running environment. To avoid losing your environment's configuration when you terminate it, you can use saved configurations to save your settings and later apply them to another environment.

To save settings in your source code, you can include configuration files. Settings in configuration files are applied every time you create an environment or deploy your application. You can also use configuration files to install packages, run scripts, and perform other instance customization operations during deployments.

Settings applied in the Elastic Beanstalk console override the same settings in configuration files, if they exist. This lets you have default settings in configuration files, and override them with environment-specific settings in the console. For more information about precedence, and other methods of changing settings, see Configuration options.

For details about the various ways you can extend an Elastic Beanstalk Linux-based platform, see Extending Elastic Beanstalk Linux platforms.

Configuring your Ruby environment

You can use the Elastic Beanstalk console to enable log rotation to Amazon S3 and configure variables that your application can read from the environment.

To access the software configuration settings for your environment
  1. Open the Elastic Beanstalk console, and in the Regions list, select your AWS Region.

  2. In the navigation pane, choose Environments, and then choose the name of your environment from the list.


    If you have many environments, use the search bar to filter the environment list.

  3. In the navigation pane, choose Configuration.

  4. In the Updates, monitoring, and logging configuration category, choose Edit.

Log options

The Log options section has two settings:

  • Instance profile– Specifies the instance profile that has permission to access the Amazon S3 bucket associated with your application.

  • Enable log file rotation to Amazon S3 – Specifies whether log files for your application's Amazon EC2 instances are copied to the Amazon S3 bucket associated with your application.

Static files

To improve performance, you can use the Static files section to configure the proxy server to serve static files (for example, HTML or images) from a set of directories inside your web application. For each directory, you set the virtual path to directory mapping. When the proxy server receives a request for a file under the specified path, it serves the file directly instead of routing the request to your application.

For details about configuring static files using configuration files or the Elastic Beanstalk console, see Serving static files.

By default, the proxy server in a Ruby environment is configured to serve static files as follows:

  • Files in the public folder are served from the /public path and the domain root (/ path).

  • Files in the public/assets subfolder are served from the /assets path.

The following examples illustrate how the default configuration works:

  • If your application source contains a file named logo.png in a folder named public, the proxy server serves it to users from and

  • If your application source contains a file named logo.png in a folder named assets inside the public folder, the proxy server serves it from

You can configure additional mappings for static files. For more information, see Ruby configuration namespaces later in this topic.


For platform versions prior to Ruby 2.7 AL2 version 3.3.7, the default Elastic Beanstalk nginx proxy server configuration doesn't support serving static files from the domain root ( This platform version was released on October 21, 2021. For more information see New platform versions - Ruby in the AWS Elastic Beanstalk Release Notes.

Environment properties

The Environment Properties section lets you specify environment configuration settings on the Amazon EC2 instances that are running your application. Environment properties are passed in as key-value pairs to the application.

The Ruby platform defines the following properties for environment configuration:

  • BUNDLE_WITHOUT – A colon-separated list of groups to ignore when installing dependencies from a Gemfile.

  • BUNDLER_DEPLOYMENT_MODE – Set to true (the default) to install dependencies in deployment mode using Bundler. Set to false to run bundle install in development mode.


    This environment property isn't defined on Amazon Linux AMI Ruby platform branches (preceding Amazon Linux 2).

  • RAILS_SKIP_ASSET_COMPILATION – Set to true to skip running rake assets:precompile during deployment.

  • RAILS_SKIP_MIGRATIONS – Set to true to skip running rake db:migrate during deployment.

  • RACK_ENV – Specify the environment stage for Rack. For example, development, production, or test.

Inside the Ruby environment running in Elastic Beanstalk, environment variables are accessible using the ENV object. For example, you could read a property named API_ENDPOINT to a variable with the following code:

endpoint = ENV['API_ENDPOINT']

See Environment properties and other software settings for more information.

Ruby configuration namespaces

You can use a configuration file to set configuration options and perform other instance configuration tasks during deployments. Configuration options can be defined by the Elastic Beanstalk service or the platform that you use and are organized into namespaces.

You can use the aws:elasticbeanstalk:environment:proxy:staticfiles namespace to configure the environment proxy to serve static files. You define mappings of virtual paths to application directories.

The Ruby platform doesn't define any platform-specific namespaces. Instead, it defines environment properties for common Rails and Rack options.

The following configuration file specifies a static files option that maps a directory named staticimages to the path /images, sets each of the platform defined environment properties, and sets an additional environment property named LOGGING.

Example .ebextensions/ruby-settings.config
option_settings: aws:elasticbeanstalk:environment:proxy:staticfiles: /images: staticimages aws:elasticbeanstalk:application:environment: BUNDLE_WITHOUT: test BUNDLER_DEPLOYMENT_MODE: true RACK_ENV: development RAILS_SKIP_ASSET_COMPILATION: true RAILS_SKIP_MIGRATIONS: true LOGGING: debug

The BUNDLER_DEPLOYMENT_MODE environment property and the aws:elasticbeanstalk:environment:proxy:staticfiles namespace aren't defined on Amazon Linux AMI Ruby platform branches (preceding Amazon Linux 2).

Elastic Beanstalk provides many configuration options for customizing your environment. In addition to configuration files, you can also set configuration options using the console, saved configurations, the EB CLI, or the AWS CLI. See Configuration options for more information.