AWS Container Services: ECS, EKS, and Fargate

AWS offers two container orchestrators (ECS and EKS) and two compute modes (EC2 launch type and Fargate). Picking the right combination depends on your team's familiarity with Kubernetes and how much of the cluster you want to manage.

Amazon ECS (Elastic Container Service):

• AWS-proprietary orchestrator — simpler than Kubernetes, tightly integrated with IAM, CloudWatch, ALB, and App Mesh.
• Concepts: Task Definition (container blueprint), Task (running instance), Service (maintains N tasks behind a load balancer), Cluster (logical grouping).
• Best when your team wants containers without Kubernetes' operational overhead.

Amazon EKS (Elastic Kubernetes Service):

• Managed upstream Kubernetes control plane with AWS integrations (IAM for Service Accounts, VPC CNI, EBS CSI, Load Balancer Controller).
• Kubernetes API is 100% compliant, so off-the-shelf Helm charts, operators, and tooling work as-is.
• Best when you already run Kubernetes, want portability across clouds, or need Kubernetes-native ecosystem tools.

AWS Fargate:

• Serverless compute for containers — you specify CPU and memory per task/pod, AWS provisions the underlying infrastructure.
• No EC2 instances to patch, scale, or right-size; billed per vCPU-second and GB-second.
• Works as a launch type under both ECS and EKS.
• Trade-offs: higher per-hour cost than equivalent EC2, no privileged containers, no daemonsets in EKS, no GPU support.

Choosing the Combination:

• ECS + Fargate: Simplest path — no cluster nodes, no Kubernetes. Great default for small teams.
• ECS + EC2: More control and lower cost at scale; use Spot for batch workloads.
• EKS + Fargate: Kubernetes API without managing nodes — good for stateless web services.
• EKS + EC2 (or Karpenter): Full Kubernetes flexibility with managed node groups or Karpenter for just-in-time node provisioning across instance types and Spot.

Related Services:

• ECR (Elastic Container Registry): Private Docker/OCI registry with IAM auth, image scanning, and pull-through cache from Docker Hub/GitHub.
• App Runner: Even simpler than ECS+Fargate — hand AWS a Dockerfile or source repo and get a URL. Limited configurability; fine for stateless web apps.
• App Mesh / VPC Lattice: Service mesh for cross-service networking, observability, and mTLS.