Build and deploy .NET web applications to ARM-powered AWS Graviton 2 Amazon ECS Clusters using AWS CDK

With .NET providing first-class support for ARM architecture, running .NET applications on an AWS Graviton processor provides you with more choices to help optimize performance and cost. We have already written about .NET 5 with Graviton benchmarks; in this post, we explore how C#/.NET developers can take advantages of Graviton processors and obtain this performance at scale with Amazon Elastic Container Service (Amazon ECS).

In addition, we take advantage of infrastructure as code (IaC) by using the AWS Cloud Development Kit (AWS CDK) to define the infrastructure .

The AWS CDK is an open-source development framework to define cloud applications in code. It includes constructs for Amazon ECS resources, which allows you to deploy fully containerized applications to AWS.

Architecture overview

Our target architecture for our .NET application running in AWS is a load balanced ECS cluster, as shown in the following diagram.

Figure: Show load balanced Amazon ECS Cluster running .NET application

We need to provision many components in this architecture, but this is where the AWS CDK comes in. AWS CDK is an open source-software development framework to define cloud resources using familiar programming languages. You can use it for the following:

A multi-stage .NET application container build
Create an Amazon Elastic Container Registry (Amazon ECR) repository and push the Docker image to it
Use IaC written in .NET to provision the preceding architecture

The following diagram illustrates how we use these services.

Show pplication and Infrastructure code written in .NET

Figure: Show Application and Infrastructure code written in .NET

Setup the development environment

To deploy this solution on AWS, we use the AWS Cloud9 development environment.

On the AWS Cloud9 console, choose Create environment.
For Name, enter a name for the environment.
Choose Next step.
On the Environment settings page, keep the default settings:
1. Environment type – Create a new EC2 instance for the environment (direct access)
2. Instance type – t2.micro (1 Gib RAM + 1 vCPU)
3. Platform – Amazon Linux 2(recommended)
Figure: Show Cloud9 Environment settings
Choose Next step.
Choose Create environment.

When the Cloud9 environment is ready, proceed to the next section.

Install the .NET SDK

The AWS development tools we require will already be setup in the Cloud9 environment, however the .NET SDK will not be available.

Install the .NET SDK with the following code from the Cloud9 terminal:

curl -sSL https://dot.net/v1/dotnet-install.sh | bash /dev/stdin -c 5.0
export PATH=$PATH:$HOME/.local/bin:$HOME/bin:$HOME/.dotnet

Verify the expected version has been installed:

dotnet --version

Figure: Show installed .NET SDK version

Clone and explore the example code

Clone the example repository:

git clone https://github.com/aws-samples/aws-cdk-dotnet-graviton-ecs-example.git

This repository contains two .NET projects, the web application, and the IaC application using the AWS CDK.

The unit of deployment in the AWS CDK is called a stack. All AWS resources defined within the scope of a stack, either directly or indirectly, are provisioned as a single unit.

The stack for this project is located within /cdk/src/Cdk/CdkStack.cs. When we read the C# code, we can see how it aligns with the architecture diagram at the beginning of this post.

First, we create a virtual private cloud (VPC) and assign a maximum of two Availability Zones:

var vpc = new Vpc(this, "DotNetGravitonVpc", new VpcProps { MaxAzs = 2 });

Next, we define the cluster and assign it to the VPC:

var cluster = new Cluster(this, "DotNetGravitonCluster", new ClusterProp { Vpc = vpc });

The Graviton instance type (c6g.4xlarge) is defined in the cluster capacity options:

cluster.AddCapacity("DefaultAutoScalingGroupCapacity",
    new AddCapacityOptions
    {
        InstanceType = new InstanceType("c6g.4xlarge"),
        MachineImage = EcsOptimizedImage.AmazonLinux2(AmiHardwareType.ARM)
    });

Finally, ApplicationLoadBalancedEC2Service is defined, along with a reference to the application source code:

new ApplicationLoadBalancedEc2Service(this, "Service",
    new ApplicationLoadBalancedEc2ServiceProps
    {
        Cluster = cluster,
        MemoryLimitMiB = 8192,
        DesiredCount = 2,
        TaskImageOptions = new ApplicationLoadBalancedTaskImageOptions
        {
            Image = ContainerImage.FromAsset(Path.Combine(Directory.GetCurrentDirectory(), @"../app")),                        
        }                             
    });

With about 30 lines of AWS CDK code written in C#, we achieve the following:

Build and package a .NET application within a Docker image
Push the Docker image to Amazon Elastic Container Registry (Amazon ECR)
Create a VPC with two Availability Zones
Create a cluster with a Graviton c6g.4xlarge instance type that pulls the Docker image from Amazon ECR

The AWS CDK has several useful helpers, such as the FromAsset function:

Image =  ContainerImage.FromAsset(Path.Combine(Directory.GetCurrentDirectory(), @"../app")),

The ContainerImage.FromAsset function instructs the AWS CDK to build the Docker image from a Dockerfile, automatically create an Amazon ECR repository, and upload the image to the repository.

For more information about the ContainerImage class, see ContainerImage.

Build and deploy the project with the AWS CDK Toolkit

The AWS CDK Toolkit, the CLI command cdk, is the primary tool for interaction with AWS CDK apps. It runs the app, interrogates the application model you defined, and produces and deploys the AWS CloudFormation templates generated by the AWS CDK.

If an AWS CDK stack being deployed uses assets such as Docker images, the environment needs to be bootstrapped. Use the cdk bootstrap command from the /cdk directory:

cdk bootstrap

Now you can deploy the stack into the AWS account with the deploy command:

cdk deploy

The AWS CDK Toolkit synthesizes fresh CloudFormation templates locally before deploying anything. The first time this runs, it has a changeset that reflects all the infrastructure defined within the stack and prompts you for confirmation before running.

When the deployment is complete, the load balancer DNS is in the Outputs section.

Figure: Show stack outputs

You can navigate to the load balancer address via a browser.

Figure: Show browser navigating to .NET application

Tracking the drift

Typically drift is a change that happens outside of the Infrastructure as Code, for example, code updates to the .NET application.

To support changes, the AWS CDK Toolkit queries the AWS account for the last deployed CloudFormation template for the stack and compares it with the locally generated template. Preview the changes with the following code:

cdk diff

If a simple text change within the application’s home page HTML is made (app/webapp/Pages/Index.cshtml), a difference is detected within the assets, but not all the infrastructure as per the first deploy.

Figure: Show cdk diff output

Running cdk deploy again now rebuilds the Docker image, uploads it to Amazon ECR, and refreshes the containers within the ECS cluster.

cdk deploy

Figure: Show browser navigating to updated .NET application

Clean up

Remove the resources created in this post with the following code:

cdk destroy

Conclusion

Using the AWS CDK to provision infrastructure in .NET provides rigor, clarity, and reliability in a language familiar to .NET developers. For more information, see Infrastructure as Code.

This post demonstrates the low barrier to entry for .NET developers wanting to apply modern application development practices while taking advantage of the price performance of ARM-based processors such as Graviton.

To learn more about building and deploying .NET applications on AWS visit our .NET Developer Center.

About the author

Author Matt Laver

Matt Laver is a Solutions Architect at AWS working with SMB customers in the UK. He is passionate about DevOps and loves helping customers find simple solutions to difficult problems.

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