Azure Container Apps Deep Dive: The Future of Serverless Containers

Azure Container Apps is Microsoft’s answer to the complexity of Kubernetes while maintaining the power of containerization. In this deep dive, we’ll explore its architecture, features, and practical implementations.

What Are Azure Container Apps?

Azure Container Apps is a fully managed serverless container service that enables you to run microservices and containerized applications without managing infrastructure. It’s built on top of Kubernetes and Dapr but abstracts away the complexity.

Architecture Overview

Container Apps run within a Container Apps Environment, which provides a secure boundary for your applications. Multiple apps can share the same environment and communicate securely.

resource environment 'Microsoft.App/managedEnvironments@2022-01-01-preview' = {
  name: 'my-container-environment'
  location: location
  properties: {
    appLogsConfiguration: {
      destination: 'log-analytics'
      logAnalyticsConfiguration: {
        customerId: logAnalytics.properties.customerId
        sharedKey: logAnalytics.listKeys().primarySharedKey
      }
    }
  }
}

Creating Your First Container App

Here’s a complete example of deploying a container app with HTTP ingress:

resource containerApp 'Microsoft.App/containerApps@2022-01-01-preview' = {
  name: 'api-service'
  location: location
  properties: {
    managedEnvironmentId: environment.id
    configuration: {
      activeRevisionsMode: 'Multiple'
      ingress: {
        external: true
        targetPort: 8080
        traffic: [
          {
            latestRevision: true
            weight: 100
          }
        ]
      }
      secrets: [
        {
          name: 'connection-string'
          value: connectionString
        }
      ]
    }
    template: {
      containers: [
        {
          name: 'api'
          image: 'myregistry.azurecr.io/api:v1'
          resources: {
            cpu: json('0.5')
            memory: '1Gi'
          }
          env: [
            {
              name: 'CONNECTION_STRING'
              secretRef: 'connection-string'
            }
          ]
        }
      ]
      scale: {
        minReplicas: 1
        maxReplicas: 30
        rules: [
          {
            name: 'http-scaling'
            http: {
              metadata: {
                concurrentRequests: '100'
              }
            }
          }
        ]
      }
    }
  }
}

Scaling with KEDA

Container Apps use KEDA (Kubernetes Event-Driven Autoscaling) under the hood. You can scale based on various triggers:

scale: {
  minReplicas: 0
  maxReplicas: 100
  rules: [
    {
      name: 'queue-scaling'
      custom: {
        type: 'azure-servicebus'
        metadata: {
          queueName: 'orders'
          messageCount: '50'
        }
        auth: [
          {
            secretRef: 'servicebus-connection'
            triggerParameter: 'connection'
          }
        ]
      }
    }
  ]
}

Dapr Integration

One of the most powerful features is built-in Dapr support:

template: {
  containers: [...]
  dapr: {
    enabled: true
    appId: 'my-app'
    appPort: 8080
    appProtocol: 'http'
  }
}

When to Use Container Apps

• Microservices that need to scale to zero
• Event-driven applications
• Background processing jobs
• APIs and web applications
• When you want Kubernetes benefits without the complexity

Azure Container Apps represents a significant step forward in making containerization accessible to all developers, not just Kubernetes experts.