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 can specify the runtime configuration for your PHP 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.

For PHP version 7.4 and later, you must include the runtime_config and operating_system settings in your app.yaml to specify an operating system. You can optionally specify a runtime version by including the runtime_version setting in your app.yaml. By default, the latest PHP version is used if the runtime_version setting is not specified.

v7.4 and later

    runtime: php
    env: flex

        operating_system: "ubuntu22"
        document_root: .

v7.3 and earlier

runtime: php
env: flex

  document_root: web
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 PHP 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
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.