AWS Elastic Container Service (ECS) has long been favored for its simplicity and deep AWS integration. But with Kubernetes becoming the de facto standard for container orchestration, many teams are transitioning from ECS to Amazon EKS (Elastic Kubernetes Service). Whether driven by a need for portability, enhanced tooling, or future-proofing, migrating to EKS is a major architectural step. This blog outlines a comprehensive, step-by-step guide for a smooth ECS to EKS migration.

Why Migrate from ECS to EKS?

  • Cross-Cloud Portability: Kubernetes workloads can run anywhere.
  • Open Ecosystem: Helm, ArgoCD, Flux, and other tools extend capabilities.
  • Scalability and Resilience: EKS supports horizontal, vertical, and spot-based scaling with tools like Karpenter.
  • DevOps Alignment: Kubernetes aligns better with GitOps, IaC, and modern CI/CD workflows.

Pre-Migration Checklist

  1. Inventory ECS services, task definitions, networking (VPC, subnets), and IAM policies.
  2. Identify secrets, environment variables, and storage dependencies.
  3. Assess traffic patterns and uptime requirements.
  4. Define a phased migration strategy with rollback points.

Provisioning EKS Infrastructure

  1. Create EKS clusters using Terraform, Pulumi, or eksctl.
  2. Set up networking: VPC, subnets, NAT gateways, and ingress.
  3. Configure IAM Roles for Service Accounts (IRSA) to allow secure pod access.
  4. Deploy core add-ons: CoreDNS, kube-proxy, VPC CNI plugin.

Converting Workloads

  1. Translate ECS task definitions into Kubernetes manifests (Deployments, Services, ConfigMaps).
  2. Use Helm or Kustomize for templating and config versioning.
  3. Store sensitive data using Kubernetes Secrets or AWS Secrets Manager.
  4. Conduct dry runs using kind or minikube.

CI/CD and Deployment Pipelines Update existing pipelines to use kubectl, helm, or GitOps tools like ArgoCD. Establish automated canary releases and rollbacks for safer deployments.

Observability and Monitoring

  1. Integrate Prometheus and Grafana for metrics.
  2. Use Fluent Bit, Loki, or OpenTelemetry for logging and tracing.
  3. Leverage CloudWatch Container Insights and AWS X-Ray.

Cost Optimization Tips

  • Use spot nodes with Karpenter or Cluster Autoscaler.
  • Set pod limits/requests carefully.
  • Right-size EBS volumes and use gp3 for lower costs.

Conclusion

Migrating from ECS to EKS can seem complex, but it brings your infrastructure in line with the future of cloud-native computing. With Kubernetes skills increasingly in demand, making the move now ensures your team stays competitive and your platform remains adaptable.

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Last Update: April 22, 2025

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