ASP.NET Core is a new open-source and cross-platform framework for building modern cloud-based and internet-connected applications using the C# programming language.

In this lab, you will deploy a simple ASP.NET Core app to App Engine flexible environment. This codelab builds on the Build and launch ASP.NET Core app from Google Cloud Shell codelab. You might want to do that lab first before attempting this lab.

Google App Engine applications are easy to create, maintain, and scale as your traffic and data storage needs change. With App Engine, there are no servers to manage. You simply upload your application and it's ready to go.

App Engine applications automatically scale based on incoming traffic. App Engine natively supports load balancing, microservices, authorization, SQL and NoSQL databases, Memcache, traffic splitting, logging, search, versioning, roll out and roll backs, and security scanning, all of which are highly customizable.

App Engine's environments, the standard environment and the flexible environment, support a host of programming languages, including C#, Java, Python, PHP, Node.js, Go, and more. The two environments give users maximum flexibility in how their application behaves, since each environment has certain strengths. For more information, read Choosing an App Engine Environment.

What you'll learn

What you'll need

How will you use this tutorial?

Read it through only Read it and complete the exercises

How would rate your experience with Google Cloud Platform?

Novice Intermediate Proficient

Self-paced environment setup

If you don't already have a Google Account (Gmail or Google Apps), you must create one. Sign-in to Google Cloud Platform console ( and create a new project:

Screenshot from 2016-02-10 12:45:26.png

Remember the project ID, a unique name across all Google Cloud projects (the name above has already been taken and will not work for you, sorry!). It will be referred to later in this codelab as PROJECT_ID.

Next, you'll need to enable billing in the Cloud Console in order to use Google Cloud resources.

Running through this codelab shouldn't cost you more than a few dollars, but it could be more if you decide to use more resources or if you leave them running (see "cleanup" section at the end of this document).

New users of Google Cloud Platform are eligible for a $300 free trial.

Start Cloud Shell

While Google Cloud can be operated remotely from your laptop, in this codelab you will be using Google Cloud Shell, a command line environment running in the Cloud.

Activate Google Cloud Shell

From the GCP Console click the Cloud Shell icon on the top right toolbar:

Then click "Start Cloud Shell":

It should only take a few moments to provision and connect to the environment:

This virtual machine is loaded with all the development tools you'll need. It offers a persistent 5GB home directory, and runs on the Google Cloud, greatly enhancing network performance and authentication. Much, if not all, of your work in this lab can be done with simply a browser or your Google Chromebook.

Once connected to the cloud shell, you should see that you are already authenticated and that the project is already set to your PROJECT_ID.

Run the following command in the cloud shell to confirm that you are authenticated:

gcloud auth list

Command output

Credentialed accounts:
 - <myaccount>@<mydomain>.com (active)
gcloud config list project

Command output

project = <PROJECT_ID>

If it is not, you can set it with this command:

gcloud config set project <PROJECT_ID>

Command output

Updated property [core/project].

In Cloud Shell prompt, you can verify that dotnet command line tool is already installed by checking its version. This should print the version of the installed dotnet command line tool:

dotnet --version

Next, create a new skeleton ASP.NET Core web app.

dotnet new mvc -o HelloWorldAspNetCore

This should create a project and restore its dependencies. You should see a message similar to below.

Restore completed in 11.44 sec for HelloWorldAspNetCore.csproj.

Restore succeeded.

We're almost ready to run our app. Navigate to the app folder.

cd HelloWorldAspNetCore

Finally, run the app.

dotnet run --urls=http://localhost:8080

Application starts listening on port 8080.

Hosting environment: Production
Content root path: /home/atameldev/HelloWorldAspNetCore
Now listening on: http://[::]:8080
Application started. Press Ctrl+C to shut down.

To verify that the app is running, click on the web preview button on the top right and select ‘Preview on port 8080'.


You'll see the default ASP.NET Core webpage:

Once you verified that the app is running, press Ctrl+C to shut down the app.

Now, publish the app to get a self-contained DLL using the dotnet publish command.

dotnet publish -c Release

Running publish displays some messages with a successfully published DLL at the end of the process.

HelloWorldAspNetCore -> /home/atameldev/HelloWorldAspNetCore/bin/Release/netcoreapp2.1/HelloWorldAspNetCore.dll

Navigate to the the publish folder for the next step.

cd bin/Release/netcoreapp2.1/publish/

The app.yaml file describes how to deploy the app to App Engine, in this case, the App Engine flexible environment. Create an app.yaml file inside publish folder.

Edit the generated app.yaml file and specify the environment as flex and runtime as aspnetcore.

env: flex
runtime: aspnetcore

Once you've saved the app.yaml file to the publish directory, you're ready to deploy your app to App Engine flexible using gcloud. Just follow the prompts to create an App Engine application.

gcloud app deploy --version v0

During deployment, you will be asked to choose a region for your application. Chose a region where you want your app to run in.

Please choose a region for your application. After choosing a region, 
you cannot change it. Which region would you like to choose?
 [1] europe-west   (supports standard and flexible)
 [2] us-central    (supports standard and flexible)
 [3] us-east1      (supports standard and flexible)
 [4] asia-northeast1 (supports standard and flexible)
 [5] cancel

This will create an image for your application in the cloud, save that image to Google Container Registry and deploy to App Engine. During deployment, you can actually see the container image being built:

Operation completed over 1 objects/571.8 KiB.
Step #0: Pulling image:
Step #0: sha256:d7b7975acb374fc3a9655a4e529993e6270cfa78023885684626528bc379f8eb: Pulling from gcp-runtimes/aspnetcorebuild

In the end, you should see that the app is deployed.

Deployed service [default] to [https://<project-id>]

After you've deployed the application,visit it by opening the URL http://<project-id> in your web browser.

You'll see the default ASP.NET Core webpage in a new tab.

You can also take a look at the container image created for you in the cloud. In cloud console, go to Container Registry > Images and then in appengine folder, you should see the image for your application.

At some point, the application that you've deployed to production will require bug fixes or additional features. App Engine is here to help you deploy a new version to production without impacting your users.

First, let's modify the application. Open the code editor from Cloud Shell.

Navigate to Index.cshtml under Pages folder of HelloWorldAspNetCore and update one of the default messages:

Learn how to build ASP.NET apps that can run anywhere.

And change it to this.

Learn how to build ASP.NET apps that can run on Google Cloud!

Save the changes and then go back to Cloud Shell. Inside HelloWorldAspNetCore,publish the app to get a self-contained DLL.

dotnet publish -c Release

Navigate to the publish directory.

cd bin/Release/netcoreapp2.1/publish/

You can now deploy a new version of your app (v1 in this case).

gcloud app deploy --version v1

Once it's deployed, you can go to App Engine versions section of Google Cloud Console to see the new version of your app serving all of the traffic with the new message.

In App Engine, under Dashboard section, you can see a number of dashboards for your application for latency, CPU etc. Explore them on your own.

Under Versions section, you can see the deployed versions of your app and you can split traffic between different versions in Traffic Splitting section. Let's split the traffic between two versions:


It's time to shutdown the app to save on cost and to be an overall good cloud citizen.

Go to the versions section of App Engine.

Select the version and stop it.

Once the version is stopped, the backing instances will be deleted and you should see instance count to drop down to zero.

What we've covered

There! You've created an ASP.NET Core app, packaged it as a Docker container, and deployed it to Google App Engine Flexible.

Next Steps


This work is licensed under a Creative Commons Attribution 2.0 Generic License.