Migrating from ECS to EKS: A Comprehensive Guide

Amazon ECS (Elastic Container Service) is a reliable container orchestration service for running Docker containers in a managed environment. However, as organizations scale and demand more flexibility, many are making the strategic shift from ECS to EKS (Elastic Kubernetes Service) to take advantage of Kubernetes’ rich ecosystem, community support, and extensibility.

At Kapstan, we help engineering teams navigate this transition smoothly. Whether you’re dealing with scalability bottlenecks, vendor lock-in concerns, or simply aiming to future-proof your infrastructure, migrating from ECS to EKS can be a game-changing move—when done right.

Why Move from ECS to EKS?

1. Kubernetes Ecosystem and Portability
While ECS is tightly integrated into AWS, EKS offers access to the broader Kubernetes ecosystem. Tools like Helm, ArgoCD, and Istio are native to Kubernetes but not ECS. Migrating to EKS allows your team to tap into a global pool of open-source solutions and talent.

2. Vendor-Neutral Architecture
One limitation of ECS is its deep dependency on AWS. EKS, being a managed Kubernetes service, promotes infrastructure portability. This flexibility is invaluable for businesses considering a multi-cloud or hybrid strategy.

3. Better Workload Management and Autoscaling
EKS gives finer control over workload placement, resource requests, and horizontal pod autoscaling. Combined with tools like Cluster Autoscaler or Karpenter, you can optimize infrastructure usage more efficiently than in ECS.

4. DevOps Enablement
From GitOps to CI/CD pipelines using tools like Flux and Jenkins, EKS simplifies modern DevOps practices, enabling engineering velocity.

Common Migration Scenarios

At Kapstan, we’ve supported a range of ECS to EKS transitions. The common migration types include:

• EC2-backed ECS to EC2-based EKS: Often done when teams want to retain granular control over nodes.

• Fargate ECS to Fargate EKS: Preferred by teams who value serverless infrastructure.

• ECS with custom tooling to EKS with GitOps: Enables streamlined, declarative deployments and infrastructure as code (IaC).

Understanding your current setup is the first step. This includes cataloging services, container images, networking policies, IAM permissions, and storage volumes.

ECS to EKS Migration: Step-by-Step Breakdown

1. Audit and Planning
Start with a comprehensive audit of your ECS services. Map dependencies, IAM roles, service discovery mechanisms, logging, monitoring, and autoscaling policies.

2. Container Image Portability
Ensure that your container images stored in Amazon ECR or another registry are compatible with Kubernetes. Check for OS, language, and library dependencies.

3. Define Kubernetes Manifests
In ECS, task definitions and service specs are used. In EKS, you’ll need to define YAML manifests for:

• Deployments

• Services

• ConfigMaps/Secrets

• HorizontalPodAutoscalers (HPAs)

• Ingress rules

Kapstan can help you create scalable, reusable Helm charts or use tools like Kustomize for better configuration management.

4. Networking and Load Balancing
Translate ECS-specific networking (e.g., awsvpc mode) to Kubernetes equivalents. This involves configuring CNI plugins, security groups, and deploying AWS Load Balancer Controller or NGINX Ingress.

5. IAM and RBAC Integration
Use IAM Roles for Service Accounts (IRSA) to bridge AWS permissions with Kubernetes Role-Based Access Control (RBAC). ECS IAM policies don’t map 1:1 to Kubernetes, so careful planning is critical.

6. Logging and Monitoring
Shift from CloudWatch-centric ECS logging to tools like Fluent Bit, Prometheus, and Grafana in EKS. You can also use Amazon CloudWatch Container Insights or integrate with Datadog and New Relic.

7. Gradual Rollout and Testing
Start with a shadow deployment—running your EKS services alongside ECS for a subset of traffic. This reduces risk and allows for performance benchmarking.

8. Cutover and Decommission ECS
Once the EKS environment proves stable under production workloads, execute the full cutover. Monitor performance, costs, and resilience closely in the days following migration.

Challenges to Watch For

Migrating from ECS to EKS isn’t without pitfalls:

• Learning curve: Kubernetes complexity can overwhelm teams unfamiliar with its concepts.

• Resource misconfiguration: Inefficient YAMLs can lead to over-provisioning or underutilization.

• Security misalignment: Misconfigured RBAC or open ingress rules can expose services.

• Downtime risk: Without blue-green or canary strategies, service cutover can impact users.

At Kapstan, we mitigate these risks through automation, infrastructure as code (using Terraform), and proactive monitoring.

How Kapstan Can Help

We offer full-lifecycle support for ECS to EKS migrations:

✅ Infrastructure audit and readiness assessment
✅ Kubernetes environment provisioning with IaC
✅ Application containerization best practices
✅ CI/CD pipeline setup (ArgoCD, GitHub Actions, Jenkins, etc.)
✅ Monitoring, alerting, and cost optimization
✅ Developer onboarding and documentation

Our engineers have led successful container migrations for startups and large enterprises alike. We bring battle-tested playbooks, automation scripts, and expert Kubernetes architects to ensure your migration is efficient and future-proof.

Final Thoughts

Making the leap from ECS to EKS is a forward-looking decision for teams ready to embrace modern cloud-native architecture. It unlocks powerful orchestration capabilities, cross-platform flexibility, and operational efficiency. But the journey demands expertise, planning, and hands-on experience.

Let Kapstan be your guide on this path. Reach out today to schedule a free migration assessment, and let’s turn your Kubernetes ambitions into production-ready realities.