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An App Engine app is configured using anapp.yamlfile, that contains CPU, memory, network and disk resources, scaling, and other
general settings including environment variables.
Aboutapp.yamlfiles
You can specify the runtime configuration for your .NET app,
including versions and URLs, in theapp.yamlfile. This file acts as a deployment descriptor of a specificserviceversion.
You must first create theapp.yamlfile for thedefaultservice of your app
before you can create and deployapp.yamlfiles for additional services.
The followingapp.yamldemonstrates how to configure your app to use the latest
.NET version. To use any othersupported versionof .NET,
you must update yourapp.yamlfile. For more information, see.NET runtime.
runtime:aspnetcoreenv:flexruntime_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/dotnet/configuring-your-app-with-app-yamlmanual_scaling:instances:1resources:cpu:1memory_gb:0.5disk_size_gb:10env_variables:# The __ in My__Greeting will be translated to a : by ASP.NET.My__Greeting:Hello AppEngine!
Depending on the complexity of your app's service, you might only need to define
a few elements in the correspondingapp.yamlfile. The following example
demonstrates what a simple .NET app might require in the
flexible environment:
You can specify a unique name for yourapp.yamlfiles, but then you must
specify the file name with thedeployment
commandas well. For example, if you name yourapp.yamlfileservice-name-app.yamlorapp.flexible.yaml, then you must deploy your app using either:
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eApp Engine apps use an \u003ccode\u003eapp.yaml\u003c/code\u003e file to configure resources, scaling, and environment settings like variables.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eapp.yaml\u003c/code\u003e file defines the runtime configuration, including the .NET version, and it acts as a deployment descriptor for a specific service version.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eapp.yaml\u003c/code\u003e for the default service must be created before creating \u003ccode\u003eapp.yaml\u003c/code\u003e files for additional services.\u003c/p\u003e\n"],["\u003cp\u003eYou can name your \u003ccode\u003eapp.yaml\u003c/code\u003e files uniquely, but you must then specify the filename when using the deployment command.\u003c/p\u003e\n"],["\u003cp\u003eSome .NET runtimes have reached end of support, and it's advised to upgrade to the latest .NET version by updating the \u003ccode\u003eapp.yaml\u003c/code\u003e file.\u003c/p\u003e\n"]]],[],null,["# Configuring your app with app.yaml\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\u003cbr /\u003e\n\n\n| **Note:** Some [.NET runtimes](/appengine/docs/flexible/lifecycle/support-schedule#net) have reached [end of support](/appengine/docs/flexible/lifecycle/runtime-lifecycle#end_of_support). You cannot re-deploy versions that use runtimes after their end of support date. We recommend that you [upgrade your app](/appengine/docs/flexible/dotnet/runtime#newversions) to use the latest version of .NET.\n\n\u003cbr /\u003e\n\n\nAn App Engine app is configured using an `app.yaml`\nfile, that contains CPU, memory, network and disk resources, scaling, and other\ngeneral settings including environment variables.\n\n\nAbout `app.yaml` files\n----------------------\n\n\u003cbr /\u003e\n\nYou can specify the runtime configuration for your .NET app, including versions and URLs, in the `app.yaml` file. This file acts as a deployment descriptor of a specific [service](/appengine/docs/flexible/an-overview-of-app-engine) version.\n\n\u003cbr /\u003e\n\n\nYou must first create the `app.yaml` file for the `default` service of your app\nbefore you can create and deploy `app.yaml` files for additional services.\n\n\nThe following `app.yaml` demonstrates how to configure your app to use the latest\n.NET version. To use any other [supported version](/appengine/docs/flexible/lifecycle/support-schedule#dotnet) of .NET,\nyou must update your `app.yaml` file. For more information, see\n[.NET runtime](/appengine/docs/flexible/dotnet/runtime). \n\n runtime: aspnetcore\n env: flex\n\n runtime_config:\n operating_system: ubuntu22\n\n # This sample incurs costs to run on the App Engine flexible environment. \n # The settings below are to reduce costs during testing and are not appropriate\n # for production use. For more information, see:\n # https://cloud.google.com/appengine/docs/flexible/dotnet/configuring-your-app-with-app-yaml\n manual_scaling:\n instances: 1\n resources:\n cpu: 1\n memory_gb: 0.5\n disk_size_gb: 10\n\n env_variables:\n # The __ in My__Greeting will be translated to a : by ASP.NET.\n My__Greeting: Hello AppEngine!\n\nDepending 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 .NET app might require in the flexible environment:\n\nYou can specify a unique name for your `app.yaml` files, but then you must\nspecify the file name with the [deployment\ncommand](/appengine/docs/flexible/testing-and-deploying-your-app)\nas well. For example, if you name your `app.yaml` file `service-name-app.yaml`\nor `app.flexible.yaml`, then you must deploy your app using either: \n\n gcloud app deploy service-name-app.yaml\n gcloud app deploy app.flexible.yaml\n\nTo learn more about structuring multiple services and `app.yaml` files in your app, see [Structuring web services](/appengine/docs/flexible/configuration-files).\n\n\u003cbr /\u003e\n\nAll configuration elements\n--------------------------\n\nFor a complete list of all the supported elements in this configuration file,\nsee the\n[`app.yaml` reference](/appengine/docs/flexible/reference/app-yaml)."]]
