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 Python 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.

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

# Copyright 2021 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

runtime: python
env: flex
entrypoint: gunicorn -b :$PORT main:app

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/python/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 Python 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.