/azure-friday-keda

Demo for Azure Friday episode on Kubernetes-Event Driven Autoscaling (KEDA).

Primary LanguageC#MIT LicenseMIT

Azure Friday - Azure Serverless on Kubernetes with KEDA

Demo used in Azure Friday on Azure Serverless on Kubernetes with KEDA episode.

Azure Friday

Scenario

We have an application that processes orders from a queue and schedules a shipment for every order.

Scenario

To coop with the load, KEDA is used to automatically scale out/in based on the current workload and to optimize for cost.

How to run the demo

Prerequisites

  • Create an Azure Service Bus namespace with orders & shipments queues
  • Install KEDA in your Kubernetes cluster (info)

Deploying the Azure Friday application

  • Provide base64 encoded secrets in deploy\deploy-app.yml with your Service Bus connection strings for our app
  • Deploy the application with kubectl apply -f deploy\deploy-app.yml

Autoscaling our .NET Core Orders worker

  • Provide base64 encoded secrets in deploy\deploy-autoscaling-orders.yml with your Service Bus connection strings for our autoscaling
  • Deploy the application with kubectl apply -f deploy\deploy-autoscaling-orders.yml

Autoscaling our Shipments Azure Function

  • Deploy the application with kubectl apply -f deploy\deploy-autoscaling-shipments.yml

License

This demo is shared under MIT license but is mainly a fork of kedacore/sample-dotnet-worker-servicebus-queue which provides a walkthrough to scale .NET Core workloads with KEDA and includes various Service Bus authentication examples.

代码调用分析

App 使用了 .net 的 host 作为外壳启动 Service https://learn.microsoft.com/en-us/dotnet/core/extensions/generic-host?tabs=appbuilder , https://github.com/cylin2000/DotNetHostTest

Src --> AzureFriday.Orders --> Program.cs Line 38 (启动后台服务: 这个服务是 RunAsync 启动后一直等待，除非收到控制台 Ctrl+C 或者 外层 Docker stop/kill 等) 
                           --> Extensions --> IserviceCollectionExtensions.cs Line 15 使用扩展启动 OrdersQueueProcessor 
                           --> OrdersQueueProcessor --> 继承自父类 QueueWorker Line 27 启动 Task.ExecuteAsync
                           --> QueueWorker Line 33  queueClient.RegisterMessageHandler(HandleMessage, HandleReceivedException);  queueClient 注册侦听 Service Bus 的消息，有消息就使用 HandleMessage 处理
                           --> 因为是异步的，所以后面的代码一直等待 queueClient 执行(Line 36: while (!stoppingToken.IsCancellationRequested))，直到外层传入 Cancellation