Container Orchestration on AWS: ECS vs EKS Comparison

Making the right choice between ECS and EKS for your containerized applications

Introduction

When deploying containerized applications on AWS, you face a critical decision: Amazon Elastic Container Service (ECS) or Amazon Elastic Kubernetes Service (EKS)? Both are powerful container orchestration platforms, but they serve different needs and come with distinct trade-offs.

This comprehensive guide compares ECS and EKS across multiple dimensions, providing practical insights to help you make an informed decision. Spoiler alert: for most organizations, especially those without existing Kubernetes investments, ECS is often the simpler, more cost-effective choice.

Quick Comparison Overview

Amazon ECS: AWS-Native Container Orchestration

What is ECS?

ECS is Amazon’s fully managed container orchestration service, deeply integrated with the AWS ecosystem. It provides a straightforward way to run Docker containers without the complexity of managing orchestration infrastructure.

ECS Architecture

┌─────────────────────────────────────────┐
│           ECS Cluster                    │
│  ┌────────────────────────────────────┐ │
│  │       ECS Service                  │ │
│  │  ┌──────────┐    ┌──────────┐     │ │
│  │  │  Task    │    │  Task    │     │ │
│  │  │┌────────┐│    │┌────────┐│     │ │
│  │  ││Container││    ││Container││     │ │
│  │  │└────────┘│    │└────────┘│     │ │
│  │  └──────────┘    └──────────┘     │ │
│  └────────────────────────────────────┘ │
└─────────────────────────────────────────┘
        ↓                    ↓
    Fargate              EC2 Instances

ECS Example: Deploying a Web Application

import * as cdk from 'aws-cdk-lib';
import * as ecs from 'aws-cdk-lib/aws-ecs';
import * as ec2 from 'aws-cdk-lib/aws-ec2';
import * as elbv2 from 'aws-cdk-lib/aws-elasticloadbalancingv2';

export class ECSWebAppStack extends cdk.Stack {
  constructor(scope: cdk.App, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    // Create VPC
    const vpc = new ec2.Vpc(this, 'VPC', {
      maxAzs: 2,
    });

    // Create ECS Cluster
    const cluster = new ecs.Cluster(this, 'Cluster', {
      vpc,
      containerInsights: true,
    });

    // Create Fargate Task Definition
    const taskDefinition = new ecs.FargateTaskDefinition(this, 'TaskDef', {
      cpu: 512,
      memoryLimitMiB: 1024,
    });

    // Add container to task
    const container = taskDefinition.addContainer('web', {
      image: ecs.ContainerImage.fromRegistry('nginx:latest'),
      logging: ecs.LogDrivers.awsLogs({ streamPrefix: 'web-app' }),
      environment: {
        ENVIRONMENT: 'production',
      },
    });

    container.addPortMappings({
      containerPort: 80,
    });

    // Create Fargate Service
    const service = new ecs.FargateService(this, 'Service', {
      cluster,
      taskDefinition,
      desiredCount: 2,
      circuitBreaker: { rollback: true },
    });

    // Create Application Load Balancer
    const alb = new elbv2.ApplicationLoadBalancer(this, 'ALB', {
      vpc,
      internetFacing: true,
    });

    const listener = alb.addListener('Listener', {
      port: 80,
    });

    listener.addTargets('ECS', {
      port: 80,
      targets: [service],
      healthCheck: {
        path: '/',
        interval: cdk.Duration.seconds(30),
      },
    });
  }
}

Lines of code: ~60

ECS Advantages

1. Simplicity

• No cluster management overhead
• Straightforward task and service definitions
• Native AWS concepts (no new orchestration paradigm)

2. Cost Efficiency

• No control plane fees
• Fargate Spot for up to 70% savings
• Efficient resource utilization

3. AWS Integration

• Seamless IAM integration (task roles)
• Native CloudWatch logging and metrics
• Direct integration with ALB/NLB
• AWS Secrets Manager and Parameter Store support
• Native VPC networking

4. Operational Simplicity

• Automatic cluster scaling
• Built-in service discovery
• Blue/green and rolling deployments
• Circuit breaker for automatic rollback

ECS Disadvantages

1. AWS Lock-in

• Cannot easily migrate to other cloud providers
• ECS-specific task definitions

2. Limited Ecosystem

• Smaller community compared to Kubernetes
• Fewer third-party tools and integrations

3. Feature Limitations

• Less flexible than Kubernetes for complex scenarios
• Limited custom scheduling capabilities

Amazon EKS: Managed Kubernetes on AWS

What is EKS?

EKS is Amazon’s managed Kubernetes service, providing a fully compatible Kubernetes control plane with AWS integration. It’s ideal for organizations with Kubernetes expertise or multi-cloud requirements.

EKS Architecture

┌─────────────────────────────────────────┐
│         EKS Control Plane               │
│      (Managed by AWS - $0.10/hr)        │
│  ┌────────────────────────────────────┐ │
│  │  API Server │ etcd │ Scheduler     │ │
│  └────────────────────────────────────┘ │
└─────────────────────────────────────────┘
                  ↓
┌─────────────────────────────────────────┐
│           Worker Nodes                   │
│  ┌────────┐  ┌────────┐  ┌────────┐    │
│  │  Pod   │  │  Pod   │  │  Pod   │    │
│  │┌──────┐│  │┌──────┐│  │┌──────┐│    │
│  ││ Cont ││  ││ Cont ││  ││ Cont ││    │
│  │└──────┘│  │└──────┘│  │└──────┘│    │
│  └────────┘  └────────┘  └────────┘    │
└─────────────────────────────────────────┘
        ↓                    ↓
    Fargate              EC2 Instances

EKS Example: Same Web Application

import * as cdk from 'aws-cdk-lib';
import * as eks from 'aws-cdk-lib/aws-eks';
import * as ec2 from 'aws-cdk-lib/aws-ec2';
import * as iam from 'aws-cdk-lib/aws-iam';

export class EKSWebAppStack extends cdk.Stack {
  constructor(scope: cdk.App, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    // Create VPC
    const vpc = new ec2.Vpc(this, 'VPC', {
      maxAzs: 2,
    });

    // Create EKS Cluster
    const cluster = new eks.Cluster(this, 'Cluster', {
      vpc,
      version: eks.KubernetesVersion.V1_28,
      defaultCapacity: 2,
      defaultCapacityInstance: ec2.InstanceType.of(
        ec2.InstanceClass.T3,
        ec2.InstanceSize.MEDIUM
      ),
    });

    // Install AWS Load Balancer Controller
    const awsLoadBalancerController = cluster.addHelmChart('AWSLoadBalancerController', {
      chart: 'aws-load-balancer-controller',
      repository: 'https://aws.github.io/eks-charts',
      namespace: 'kube-system',
      values: {
        clusterName: cluster.clusterName,
      },
    });

    // Create deployment manifest
    const deployment = {
      apiVersion: 'apps/v1',
      kind: 'Deployment',
      metadata: { name: 'web-app' },
      spec: {
        replicas: 2,
        selector: { matchLabels: { app: 'web' } },
        template: {
          metadata: { labels: { app: 'web' } },
          spec: {
            containers: [
              {
                name: 'web',
                image: 'nginx:latest',
                ports: [{ containerPort: 80 }],
                env: [
                  { name: 'ENVIRONMENT', value: 'production' },
                ],
              },
            ],
          },
        },
      },
    };

    // Create service manifest
    const service = {
      apiVersion: 'v1',
      kind: 'Service',
      metadata: { name: 'web-service' },
      spec: {
        type: 'LoadBalancer',
        selector: { app: 'web' },
        ports: [{ port: 80, targetPort: 80 }],
      },
    };

    // Apply manifests
    cluster.addManifest('web-deployment', deployment);
    cluster.addManifest('web-service', service);
  }
}

Lines of code: ~80 (plus additional Helm chart configuration)

EKS Advantages

1. Kubernetes Standard

• Industry-standard orchestration
• Portable across cloud providers
• Huge ecosystem and community

2. Advanced Features

• Custom Resource Definitions (CRDs)
• Operators for complex applications
• Advanced scheduling (node affinity, taints, tolerations)
• StatefulSets for stateful applications

3. Flexibility

• Highly customizable
• Extensive third-party tool support
• Multi-tenancy capabilities

4. Multi-Cloud Strategy

• Skills transferable across clouds
• Potential for hybrid/multi-cloud deployments
• Vendor independence

EKS Disadvantages

1. Complexity

• Steep learning curve
• More moving parts to manage
• Requires Kubernetes expertise

2. Cost

• $0.10/hour per cluster (~$73/month control plane fee)
• Higher operational overhead
• More resources needed for control plane

3. AWS Integration Friction

• Requires additional controllers (ALB controller, EBS CSI driver)
• IAM integration requires IRSA (IAM Roles for Service Accounts)
• More complex networking setup

4. Operational Overhead

• More complex troubleshooting
• Additional components to monitor
• Cluster upgrades require careful planning

Detailed Feature Comparison

1. Cost Analysis

ECS Monthly Costs (2 container instances):

Control Plane: $0
2x Fargate (0.5 vCPU, 1GB): ~$30/month
Total: ~$30/month

EKS Monthly Costs (2 container instances):

Control Plane: $73/month
2x EC2 t3.medium nodes: ~$60/month
OR 2x Fargate (0.5 vCPU, 1GB): ~$30/month
Total: ~$103-133/month

ECS wins on cost - No control plane fees make ECS significantly cheaper, especially for smaller deployments.

2. Learning Curve

ECS Learning Path:

Week 1: Docker basics
Week 2: ECS concepts (Tasks, Services, Clusters)
Week 3: Production deployment
Week 4: Advanced features (auto-scaling, monitoring)

EKS Learning Path:

Week 1-2: Docker basics
Week 3-4: Kubernetes fundamentals
Week 5-6: Kubernetes advanced concepts
Week 7-8: EKS specifics and AWS integration
Week 9-12: Production best practices

ECS wins on simplicity - Significantly shorter time to productivity.

3. Deployment Complexity

Deploy a Service with Auto-scaling:

ECS (CDK):

const service = new ecs.FargateService(this, 'Service', {
  cluster,
  taskDefinition,
  desiredCount: 2,
});

// Add auto-scaling
const scaling = service.autoScaleTaskCount({
  minCapacity: 2,
  maxCapacity: 10,
});

scaling.scaleOnCpuUtilization('CpuScaling', {
  targetUtilizationPercent: 70,
});

EKS (Kubernetes YAML):

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-app
spec:
  replicas: 2
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
      - name: web
        image: nginx:latest
        resources:
          requests:
            cpu: 500m
            memory: 1Gi
          limits:
            cpu: 1000m
            memory: 2Gi
---
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: web-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: web-app
  minReplicas: 2
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 70

ECS wins on simplicity - Less YAML, more intuitive configuration.

4. AWS Service Integration

ECS IAM Integration (Native):

// Create task role with permissions
const taskRole = new iam.Role(this, 'TaskRole', {
  assumedBy: new iam.ServicePrincipal('ecs-tasks.amazonaws.com'),
});

taskRole.addToPolicy(new iam.PolicyStatement({
  actions: ['s3:GetObject'],
  resources: ['arn:aws:s3:::my-bucket/*'],
}));

// Assign to task definition
const taskDefinition = new ecs.FargateTaskDefinition(this, 'TaskDef', {
  taskRole, // Direct assignment
});

EKS IAM Integration (Requires IRSA):

// Create service account with IAM role
const serviceAccount = cluster.addServiceAccount('S3ServiceAccount', {
  name: 's3-access',
  namespace: 'default',
});

// Add permissions
serviceAccount.addToPrincipalPolicy(new iam.PolicyStatement({
  actions: ['s3:GetObject'],
  resources: ['arn:aws:s3:::my-bucket/*'],
}));

// Reference in pod spec
const deployment = {
  // ... deployment config
  spec: {
    template: {
      spec: {
        serviceAccountName: 's3-access', // Must configure pod to use SA
        containers: [/* ... */],
      },
    },
  },
};

ECS wins on AWS integration - More straightforward, less configuration needed.

5. Multi-Region and High Availability

ECS Multi-Region:

// Deploy to multiple regions easily
const euCluster = new ecs.Cluster(this, 'EUCluster', {
  vpc: euVpc,
});

const usCluster = new ecs.Cluster(this, 'USCluster', {
  vpc: usVpc,
});

// Same service definition, different clusters
new ecs.FargateService(this, 'EUService', {
  cluster: euCluster,
  taskDefinition,
});

new ecs.FargateService(this, 'USService', {
  cluster: usCluster,
  taskDefinition,
});

EKS Multi-Region: Requires separate EKS clusters per region, more complex federation or multi-cluster management tools.

ECS wins on simplicity for multi-region deployments.

6. Ecosystem and Tooling

ECS Ecosystem:

• AWS Console (excellent UX)
• AWS CLI
• AWS CDK/CloudFormation
• Copilot CLI (AWS’s opinionated tool)
• Limited third-party tools

EKS Ecosystem:

• kubectl and Kubernetes tooling
• Helm charts (thousands available)
• Operators (database operators, monitoring, etc.)
• GitOps tools (ArgoCD, Flux)
• Service meshes (Istio, Linkerd)
• Extensive third-party ecosystem

EKS wins on ecosystem - Significantly more tools and integrations available.

When to Choose ECS

✅ Choose ECS if:

1. You’re AWS-focused - No multi-cloud requirements
2. You want simplicity - Faster time to production
3. You’re cost-sensitive - No control plane fees
4. You have a small team - Less Kubernetes expertise required
5. You prioritize AWS integration - Native IAM, CloudWatch, etc.
6. You’re building new applications - No existing Kubernetes investment

ECS Use Cases

1. Web Applications and APIs:

// Simple, cost-effective web app deployment
const webService = new ecs.FargateService(this, 'WebApp', {
  cluster,
  taskDefinition: webTaskDef,
  desiredCount: 3,
  circuitBreaker: { rollback: true },
});

2. Microservices:

// Multiple services with service discovery
const serviceDiscovery = cluster.addDefaultCloudMapNamespace({
  name: 'local',
});

const orderService = new ecs.FargateService(this, 'OrderService', {
  cluster,
  taskDefinition: orderTaskDef,
  cloudMapOptions: {
    name: 'orders',
  },
});

const paymentService = new ecs.FargateService(this, 'PaymentService', {
  cluster,
  taskDefinition: paymentTaskDef,
  cloudMapOptions: {
    name: 'payments',
  },
});

3. Batch Processing:

// Scheduled batch jobs
const batchTask = new ecs.FargateTaskDefinition(this, 'BatchTask', {
  cpu: 2048,
  memoryLimitMiB: 4096,
});

// Trigger with EventBridge
const rule = new events.Rule(this, 'ScheduleRule', {
  schedule: events.Schedule.cron({ hour: '2', minute: '0' }),
});

rule.addTarget(new targets.EcsTask({
  cluster,
  taskDefinition: batchTask,
}));

When to Choose EKS

✅ Choose EKS if:

1. You need multi-cloud portability - Kubernetes runs everywhere
2. You have Kubernetes expertise - Team already knows K8s
3. You need advanced features - Operators, CRDs, complex scheduling
4. You have complex requirements - StatefulSets, custom controllers
5. You want vendor independence - Not locked into AWS
6. You’re migrating from on-prem Kubernetes - Maintain tooling and workflows

EKS Use Cases

1. Complex Stateful Applications:

# StatefulSet for database cluster
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: postgres-cluster
spec:
  serviceName: postgres
  replicas: 3
  selector:
    matchLabels:
      app: postgres
  template:
    metadata:
      labels:
        app: postgres
    spec:
      containers:
      - name: postgres
        image: postgres:15
        volumeMounts:
        - name: data
          mountPath: /var/lib/postgresql/data
  volumeClaimTemplates:
  - metadata:
      name: data
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 100Gi

2. Multi-Tenancy:

# Namespace-based isolation
apiVersion: v1
kind: Namespace
metadata:
  name: team-a
---
apiVersion: v1
kind: ResourceQuota
metadata:
  name: team-a-quota
  namespace: team-a
spec:
  hard:
    requests.cpu: "10"
    requests.memory: 20Gi
    persistentvolumeclaims: "5"

3. Service Mesh Deployments:

# Install Istio on EKS
istioctl install --set profile=production

# Automatic sidecar injection
kubectl label namespace default istio-injection=enabled

Hybrid Approach: Using Both

Some organizations benefit from using both services:

// Use ECS for simple services
const apiService = new ecs.FargateService(this, 'API', {
  cluster: ecsCluster,
  taskDefinition: apiTaskDef,
});

// Use EKS for complex applications
const mlPlatform = new eks.Cluster(this, 'MLCluster', {
  vpc,
  version: eks.KubernetesVersion.V1_28,
});

// Deploy Kubeflow on EKS for ML workflows
mlPlatform.addHelmChart('Kubeflow', {
  chart: 'kubeflow',
  repository: 'https://kubeflow.github.io/manifests/charts',
});

Migration Paths

From ECS to EKS

If you start with ECS and later need Kubernetes:

# Convert ECS task definition to Kubernetes deployment
import json
import yaml

def ecs_to_k8s(task_definition):
    """Convert ECS task definition to K8s deployment"""
    container_def = task_definition['containerDefinitions'][0]

    k8s_deployment = {
        'apiVersion': 'apps/v1',
        'kind': 'Deployment',
        'metadata': {'name': container_def['name']},
        'spec': {
            'replicas': 2,
            'selector': {'matchLabels': {'app': container_def['name']}},
            'template': {
                'metadata': {'labels': {'app': container_def['name']}},
                'spec': {
                    'containers': [{
                        'name': container_def['name'],
                        'image': container_def['image'],
                        'ports': [{'containerPort': pm['containerPort']}
                                  for pm in container_def.get('portMappings', [])],
                        'env': [{'name': k, 'value': v}
                                for k, v in container_def.get('environment', {}).items()],
                    }]
                }
            }
        }
    }

    return yaml.dump(k8s_deployment)

From EKS to ECS

Migrating from EKS to ECS (simplification):

// Convert K8s deployment to ECS task definition
const convertToECS = (k8sDeployment: any): ecs.TaskDefinition => {
  const container = k8sDeployment.spec.template.spec.containers[0];

  const taskDef = new ecs.FargateTaskDefinition(this, 'TaskDef', {
    cpu: parseCPU(container.resources.requests.cpu),
    memoryLimitMiB: parseMemory(container.resources.requests.memory),
  });

  taskDef.addContainer('main', {
    image: ecs.ContainerImage.fromRegistry(container.image),
    portMappings: container.ports.map((p: any) => ({
      containerPort: p.containerPort,
    })),
    environment: Object.fromEntries(
      container.env.map((e: any) => [e.name, e.value])
    ),
  });

  return taskDef;
};

Cost Optimization Strategies

ECS Cost Optimization

// Use Fargate Spot for cost savings
const service = new ecs.FargateService(this, 'Service', {
  cluster,
  taskDefinition,
  capacityProviderStrategies: [
    {
      capacityProvider: 'FARGATE_SPOT',
      weight: 2,
    },
    {
      capacityProvider: 'FARGATE',
      weight: 1,
      base: 1, // Ensure at least one on regular Fargate
    },
  ],
});

// Use Graviton2 for better price-performance
const gravitonTaskDef = new ecs.FargateTaskDefinition(this, 'GravitonTask', {
  cpu: 1024,
  memoryLimitMiB: 2048,
  runtimePlatform: {
    cpuArchitecture: ecs.CpuArchitecture.ARM64,
  },
});

EKS Cost Optimization

// Use Karpenter for efficient node provisioning
const karpenter = cluster.addHelmChart('Karpenter', {
  chart: 'karpenter',
  repository: 'https://charts.karpenter.sh',
  namespace: 'karpenter',
});

// Use Spot instances for worker nodes
cluster.addAutoScalingGroupCapacity('spot-capacity', {
  instanceType: ec2.InstanceType.of(
    ec2.InstanceClass.T3,
    ec2.InstanceSize.MEDIUM
  ),
  spotPrice: '0.05',
  maxCapacity: 10,
});

The Verdict: Why ECS Often Wins

For most organizations, especially those:

• Building on AWS without multi-cloud requirements
• Prioritizing simplicity and operational efficiency
• Working with limited Kubernetes expertise
• Cost-conscious about infrastructure spend

ECS is the better choice because it provides:

1. 70% faster time to production
2. ~50% lower costs (no control plane fees)
3. Simpler operations (less to learn, manage, troubleshoot)
4. Better AWS integration (native IAM, logging, networking)
5. Lower operational overhead (managed by AWS)

However, if you:

• Need multi-cloud portability
• Have existing Kubernetes investments
• Require advanced Kubernetes features
• Have a team with strong Kubernetes expertise

Then EKS is the right choice.

Conclusion

Both ECS and EKS are excellent container orchestration platforms, but they serve different needs:

Choose ECS for:

• Simplicity and AWS integration
• Cost efficiency
• Faster time to market
• AWS-centric architecture

Choose EKS for:

• Kubernetes standardization
• Multi-cloud portability
• Advanced orchestration features
• Existing Kubernetes expertise

The pragmatic approach: Start with ECS for simplicity and lower costs. If you genuinely need Kubernetes features or portability, migrate to EKS later. Don’t choose Kubernetes “just because” - the operational complexity and cost should be justified by real requirements.

Ready to deploy containers on AWS? Contact Forrict for expert guidance on choosing and implementing the right orchestration platform for your needs.

Resources

• AWS ECS Documentation
• AWS EKS Documentation
• AWS Copilot CLI
• Kubernetes Documentation
• AWS Container Blog