AWS EKS Cluster Architecture

What this diagram shows

This diagram represents a complete AWS EKS cluster deployment, showing the managed control plane (handling API server, etcd, scheduler, controller manager), worker node groups across multiple availability zones, the ingress controller routing traffic via Application Load Balancer, container image storage in ECR, persistent storage via EBS or EFS, and the IAM role assignments that grant pod-level permissions. Data flows from external clients through the ALB to pods, while the control plane orchestrates scheduling and monitoring across all nodes.

Key components

• EKS Control Plane — AWS-managed Kubernetes API server, scheduler, and controller manager that orchestrates cluster operations without requiring you to provision master nodes.
• Node Groups — Auto Scaling Groups of EC2 instances running the kubelet and container runtime, distributed across availability zones to run your workloads.
• Application Load Balancer (ALB) — Ingress controller entry point that routes external HTTP/HTTPS traffic to Kubernetes services based on hostnames and paths.
• ECR Repository — Elastic Container Registry storing your application container images, pulled by nodes during pod deployment.
• IAM Roles for Service Accounts (IRSA) — Grants fine-grained AWS API permissions directly to pods through OpenID Connect federation, eliminating need for node-level credentials.
• EBS Volumes — Block storage for stateful workloads, provisioned dynamically via persistent volume claims.
• EFS — Shared file system for read-write-many access patterns across multiple pods and nodes in the cluster.

When to use it

Use this template when designing production or staging Kubernetes deployments on AWS that require multi-zone resilience, secure pod-to-AWS service communication, container image management, and persistent data handling. It applies to microservices architectures, containerised applications needing external traffic ingress, and teams adopting EKS as their container orchestration platform.

Common mistakes

• Placing all nodes in a single availability zone, eliminating the high-availability benefits that EKS provides through distributed control plane replication.
• Granting broad IAM permissions to node IAM roles instead of using IRSA to enforce least-privilege access per workload and service account.
• Omitting the ingress controller setup or ALB configuration, leaving no production-ready mechanism to route external traffic to cluster services.

Adapting it to your system

Replace the generic node group with your actual instance types (t3.medium, c5.large, etc.) and desired capacity. Specify your real application images in ECR with proper image URI references. Map your domain names and application services to the ALB listener rules. Define storage requirements: add EBS volumes for databases or caches, or EFS for shared file access. Adjust the IAM roles to match your AWS service dependencies (S3, RDS, SNS, etc.). Document your networking CIDR ranges, security group rules, and namespace-level pod security policies specific to your deployment.