Azure Container Services Comparison – Part 3: Scaling, Networking & Advanced Features

Azure Container Services Comparison: Container Apps vs Container Instances vs AKS

Part 3: Scaling, Networking & Advanced Features

After exploring the implementation details in Part 2, let’s dive into the advanced capabilities that differentiate these services in production environments. Scaling strategies, networking configurations, and advanced features often determine long-term success.

Scaling Strategies: From Zero to Hero

Azure Container Instances: Manual and Programmatic Scaling

ACI doesn’t provide built-in auto-scaling, but you can implement custom scaling solutions.

# Azure Function for custom ACI scaling
[FunctionName("ScaleACI")]
public static async Task<IActionResult> Run(
    [HttpTrigger(AuthorizationLevel.Function, "post")] HttpRequest req,
    ILogger log)
{
    var queueLength = await GetQueueLength();
    var currentInstances = await GetCurrentACIInstances();
    
    var desiredInstances = Math.Min(queueLength / 10, 20); // Max 20 instances
    
    if (desiredInstances > currentInstances)
    {
        for (int i = currentInstances; i < desiredInstances; i++)
        {
            await CreateACIInstance($"processor-{i}");
        }
    }
    else if (desiredInstances < currentInstances)
    {
        await ScaleDownInstances(currentInstances - desiredInstances);
    }
    
    return new OkResult();
}

ACI Scaling Characteristics:

• Scale-to-zero capable (true serverless)
• Cold start: 10-30 seconds
• Manual or custom automation required
• Perfect for batch processing and scheduled tasks

Container Apps: Event-Driven Auto-Scaling

Container Apps provides sophisticated scaling with KEDA (Kubernetes Event-Driven Autoscaler) integration.

# Advanced Container Apps scaling configuration
properties:
  template:
    scale:
      minReplicas: 0  # True scale-to-zero
      maxReplicas: 50
      rules:
      # HTTP-based scaling
      - name: http-scaling
        http:
          metadata:
            concurrentRequests: "10"
      
      # Queue-based scaling
      - name: azure-servicebus-queue
        custom:
          type: azure-servicebus
          metadata:
            queueName: "processing-queue"
            namespace: "myservicebus"
            messageCount: "5"
      
      # Custom metrics scaling
      - name: azure-monitor
        custom:
          type: azure-monitor
          metadata:
            resourceGroupName: "myResourceGroup"
            resourceName: "myAppInsights"
            metricName: "requests/count"
            targetValue: "100"
            timeWindow: "PT5M"

Container Apps Scaling Benefits:

• Scale-to-zero with fast cold starts (2-5 seconds)
• Multiple scaling triggers simultaneously
• Built-in support for 30+ event sources
• Predictive scaling based on schedules

AKS: Comprehensive Scaling Ecosystem

AKS offers the most sophisticated scaling options with multiple autoscaler types.

# Horizontal Pod Autoscaler (HPA)
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: advanced-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: web-app
  minReplicas: 2
  maxReplicas: 100
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 70
  - type: External
    external:
      metric:
        name: azure-servicebus-queue-length
      target:
        type: AverageValue
        averageValue: "10"

Advanced Features Comparison

Coming Up Next

In Part 4, we’ll analyze the real cost implications of each service with detailed pricing scenarios and explore migration strategies for moving between services as your needs evolve.

Advanced features separate good architectures from great ones. The key is choosing the service that provides the right level of sophistication without over-engineering your solution.