An App Engine app is configured using an app.yaml
file, that contains the runtime, handlers, scaling, and other general settings
including environment variables.
About app.yaml
files
You can specify the runtime configuration for your Ruby app,
including versions and URLs, in the app.yaml
file. This file acts as a deployment descriptor of a specific
service
version.
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.
Generally, your app.yaml
file requires only the runtime
element for a simple
Ruby app in the standard environment, for
example:
runtime: ruby33
App Engine provides default values for all other settings, including the F1 instance class, which determines the memory and CPU resources that are available to your app, and automatic scaling, which controls how and when new instances of your app are created.
If you need to override the default settings, create an app.yaml
file and
specify the settings you need. For more information, see
app.yaml
file reference.
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.standard.yaml
, then you must deploy your app using either:
gcloud app deploy service-name-app.yaml
gcloud app deploy app.standard.yaml
To learn more about structuring multiple services and app.yaml
files in your
app, see Structuring web services.
All configuration elements
For a complete list of all the supported elements in this configuration file,
see the
app.yaml
reference.