Previously, you could only use pre-configured Elastic Beanstalks platforms to run your applications. If you wanted to customize the environment configurations of Elastic Beanstalk's pre-configured platforms, you needed to add Elastic Beanstalk configuration files to your web applications’ source code or use the limited configuration options available in the Management Console or EB CLI. Now, you can author your own custom Elastic Beanstalk platforms and customize the Amazon Machine Image (AMI), the metadata, and the environment configuration options. This gives you the toolset to standardize your Elastic Beanstalk environments and implement best practices specific to your organization. For example, you can create Elastic Beanstalk platforms that run operating systems, languages, and application frameworks not currently supported by Elastic Beanstalk (e.g., Ubuntu, Red Hat Enterprise, Rust, Sinatra). By using your custom platforms, users in your account now can easily leverage your customizations without the need to provide instance customizations with their application bundles.