Amazon EKS (Elastic Kubernetes Service) is AWS’s managed Kubernetes service that runs the Kubernetes control plane across multiple availability zones, eliminating the need to install, operate, and maintain your own Kubernetes clusters. EKS provides a certified Kubernetes environment that’s compatible with existing plugins and tooling from the Kubernetes community while integrating deeply with AWS services.
Key Takeaways
EKS manages the Kubernetes control plane (API server, etcd, scheduler) while you manage worker nodes or use Fargate for serverless pods. It runs upstream Kubernetes, so your workloads and tools are portable across environments. You can run worker nodes on EC2 instances using managed node groups, self-managed nodes, or serverless with Fargate. EKS integrates with AWS IAM for authentication, VPC for networking, EBS and EFS for storage, and CloudWatch for monitoring. The service is suitable when you need Kubernetes features, multi-cloud portability, or existing Kubernetes expertise.
What is Amazon EKS
EKS is AWS’s fully managed Kubernetes platform. Kubernetes is an open-source container orchestration system originally developed by Google. It’s become the industry standard for deploying, scaling, and managing containerized applications.
Running Kubernetes yourself requires significant expertise. You need to set up the control plane, configure high availability, manage upgrades, secure the API server, and handle etcd backups. EKS handles all of this for you.
How EKS Works
EKS separates the Kubernetes architecture into two parts: the control plane and the data plane.
The control plane includes the Kubernetes API server, etcd database, scheduler, and controller manager. EKS runs these components across multiple availability zones for high availability. AWS patches, upgrades, and scales the control plane automatically. You interact with it through standard Kubernetes tools like kubectl.
The data plane consists of worker nodes where your containerized applications run. You have three options for managing worker nodes: managed node groups, self-managed nodes, or Fargate.
Worker Node Options
Managed Node Groups: EKS automates the provisioning and lifecycle management of EC2 instances. You specify the instance type, desired capacity, and Amazon Machine Image (AMI), and EKS handles node creation, updates, and termination. Nodes are automatically registered with the cluster and configured with the necessary Kubernetes components.
Self-Managed Nodes: You create and manage EC2 instances yourself, giving you complete control over the configuration. You’re responsible for joining nodes to the cluster, managing updates, and handling scaling. This option provides maximum flexibility but requires more operational effort.
Fargate: AWS manages the infrastructure completely. You create Fargate profiles that define which pods run serverless based on namespace and labels. Each pod runs in isolation with dedicated compute resources. You don’t provision or manage any nodes.
Core Kubernetes Concepts in EKS
Pods: The smallest deployable unit in Kubernetes. A pod contains one or more containers that share storage and network resources. Pods run on worker nodes.
Deployments: Define the desired state for your pods. Deployments manage replica sets, which ensure a specified number of pod replicas are running. They handle rolling updates and rollbacks.
Services: Provide stable network endpoints for accessing pods. Services abstract pod IP addresses, which change as pods are created and destroyed. You can expose services internally within the cluster or externally through load balancers.
Namespaces: Virtual clusters within your physical cluster. Namespaces provide scope for resource names and enable resource quotas and access controls.
Networking
EKS integrates with Amazon VPC networking. Each pod receives an IP address from your VPC subnet range. The Amazon VPC CNI (Container Network Interface) plugin enables this native VPC integration.
You control network access using security groups at the node level and Kubernetes network policies at the pod level. EKS supports both public and private API server endpoints. Private endpoints keep all cluster communication within your VPC.
For external access to services, you can use AWS Load Balancers. The AWS Load Balancer Controller provisions ALBs for ingress resources and NLBs for services with type LoadBalancer.
Storage
EKS supports multiple storage options through Kubernetes persistent volumes. The Amazon EBS CSI (Container Storage Interface) driver provisions EBS volumes for pods requiring block storage. The EFS CSI driver mounts EFS file systems for shared storage across multiple pods.
Storage classes define the type and characteristics of storage volumes. You create persistent volume claims to request storage, and Kubernetes dynamically provisions the underlying resources.
Authentication and Authorization
EKS uses AWS IAM for cluster authentication. IAM users and roles authenticate to the Kubernetes API server through AWS credentials. The aws-auth ConfigMap maps IAM identities to Kubernetes users and groups.
Authorization uses Kubernetes Role-Based Access Control (RBAC). You define roles with specific permissions and bind them to users or service accounts. IAM Roles for Service Accounts (IRSA) grants pods fine-grained AWS permissions without sharing credentials.
Add-ons and Extensions
EKS supports standard Kubernetes add-ons and AWS-specific integrations. Core DNS provides cluster DNS resolution. The VPC CNI plugin handles pod networking. The kube-proxy maintains network rules on nodes.
AWS provides additional integrations like the Load Balancer Controller, EBS CSI driver, EFS CSI driver, and CloudWatch Container Insights for monitoring. You can install these through Kubernetes manifests, Helm charts, or EKS add-ons.
Monitoring and Logging
EKS control plane logs stream to CloudWatch Logs. You can enable audit, API server, controller manager, scheduler, and authenticator logs. Container Insights collects metrics and logs from your cluster, nodes, and pods.
The Kubernetes Metrics Server provides resource metrics for pods and nodes. These metrics power horizontal pod autoscaling and kubectl top commands.
When to Use EKS
Choose EKS when you need standard Kubernetes features and APIs. It’s the right choice if you’re already using Kubernetes elsewhere and want portability. Teams with Kubernetes expertise can leverage existing knowledge and tools.
EKS works well for complex microservices architectures requiring advanced deployment strategies like blue-green or canary deployments. It suits organizations needing multi-cloud or hybrid cloud capabilities since Kubernetes runs consistently across environments.
EKS vs ECS
ECS is simpler to learn and tightly integrated with AWS services. It’s AWS-specific but requires less Kubernetes knowledge. ECS works well for straightforward container workloads on AWS.
EKS provides full Kubernetes functionality with ecosystem compatibility. It has a steeper learning curve but offers portability and advanced features. Choose based on your team’s expertise, portability requirements, and application complexity.
Conclusion
Amazon EKS delivers managed Kubernetes on AWS, handling the control plane while giving you flexibility in how you run worker nodes. It provides standard Kubernetes APIs and tooling with AWS service integration for networking, storage, security, and monitoring. EKS makes sense when you need Kubernetes capabilities, want workload portability, or have teams already skilled in Kubernetes. While more complex than ECS, EKS offers the full power of Kubernetes without the operational burden of managing the control plane yourself.