Configuring your app with app.yaml

An App Engine app is configured using an app.yaml file, that contains CPU, memory, network and disk resources, scaling, and other general settings including environment variables.

About app.yaml files

You must first create the app.yaml file for the default service of your app before you can create and deploy app.yaml files for additional services.

The following app.yaml demonstrates how to configure your app to use the latest Ruby version. To use any other supported version of Ruby, you must update your app.yaml file. For more information, see Ruby runtime .

  runtime 
 : 
  
 ruby 
 env 
 : 
  
 flex 
 entrypoint 
 : 
  
 bundle exec ruby app.rb 
 runtime_config 
 : 
  
 operating_system 
 : 
  
 ubuntu22 
 # This sample incurs costs to run on the App Engine flexible environment. 
 # The settings below are to reduce costs during testing and are not appropriate 
 # for production use. For more information, see: 
 # https://cloud.google.com/appengine/docs/flexible/ruby/configuring-your-app-with-app-yaml 
 manual_scaling 
 : 
  
 instances 
 : 
  
 1 
 resources 
 : 
  
 cpu 
 : 
  
 1 
  
 memory_gb 
 : 
  
 0.5 
  
 disk_size_gb 
 : 
  
 10 
 

Depending on the complexity of your app's service, you might only need to define a few elements in the corresponding app.yaml file. The following example demonstrates what a simple Ruby app might require in the flexible environment:

You can specify a unique name for your app.yaml files, but then you must specify the file name with the deployment command as well. For example, if you name your app.yaml file service-name-app.yaml or app.flexible.yaml , then you must deploy your app using either:

  gcloud 
  
 app 
  
 deploy 
  
 service 
 - 
 name 
 - 
 app 
 . 
 yaml 
 gcloud 
  
 app 
  
 deploy 
  
 app 
 . 
 flexible 
 . 
 yaml 
 

All configuration elements

For a complete list of all the supported elements in this configuration file, see the app.yaml reference .