Amazon EKS (Elastic Kubernetes Service)
7 questions found
What is Amazon EKS and why would a team choose it over ECS?
Beginner
Amazon EKS, or Elastic Kubernetes Service, is a fully managed service that runs the open source Kubernetes container orchestration platform on AWS, managing the Kubernetes control plane for you, and teams often choose it when they already have Kubernetes expertise or need the portability of running the exact same Kubernetes configuration across multiple cloud providers or on premises environments.
aws eks create-cluster --name my-cluster --role-arn arn:aws:iam::123456789012:role/eksClusterRole --resources-vpc-config subnetIds=subnet-12345
Real-world example
A company that already runs Kubernetes workloads on premises migrates to EKS to keep using the exact same Kubernetes manifests and tools its team is familiar with, while offloading the operational burden of managing the control plane.
Common follow-ups: What is the difference between EKS and self managed Kubernetes on EC2?;Does EKS support both Fargate and EC2 worker nodes?
Amazon ECS (Elastic Container Service);AWS Fargate
What is the Kubernetes control plane, and how does EKS manage it?
Beginner
The Kubernetes control plane is the set of components responsible for making decisions about the cluster, such as scheduling containers and maintaining the desired state of the system, and with EKS, AWS fully manages this control plane across multiple Availability Zones for high availability, automatically handling patching, scaling, and failover so you only need to focus on managing your own worker nodes and workloads.
aws eks describe-cluster --name my-cluster --query cluster.status
Real-world example
A development team running EKS never needs to worry about patching or scaling the Kubernetes API server, since AWS automatically manages that part of the cluster, letting the team focus purely on deploying their applications.
Common follow-ups: What is the difference between the control plane and worker nodes?;How does EKS ensure control plane high availability?
AWS Global Infrastructure (Regions
AZs & Edge Locations);Auto Scaling Groups
What are EKS managed node groups, and how do they simplify worker node management?
Intermediate
EKS managed node groups automate the provisioning and lifecycle management of the EC2 instances that serve as worker nodes in your cluster, handling tasks such as applying the correct Amazon Machine Image, joining nodes to the cluster automatically, and performing rolling updates when you need to upgrade node versions, significantly reducing the manual operational work compared to managing worker nodes yourself.
aws eks create-nodegroup --cluster-name my-cluster --nodegroup-name my-nodes --subnets subnet-12345 --node-role arn:aws:iam::123456789012:role/NodeInstanceRole
Real-world example
A platform team upgrades all worker nodes in its EKS cluster to a newer Kubernetes version using a managed node group's rolling update feature, avoiding the need to manually replace each EC2 instance one at a time.
Common follow-ups: What is the difference between managed node groups and self managed node groups?;Can EKS worker nodes run on Fargate instead of EC2?
Auto Scaling Groups;EC2 & Compute
How does EKS integrate with IAM for authentication and authorization within a Kubernetes cluster?
Intermediate
EKS integrates with IAM through a feature that maps IAM users and roles to Kubernetes role based access control permissions, and more recently through IAM Roles for Service Accounts, which lets individual Kubernetes pods assume specific IAM roles, giving each application running in the cluster only the exact AWS permissions it needs rather than sharing broad node level permissions.
eksctl create iamserviceaccount --name my-service-account --cluster my-cluster --attach-policy-arn arn:aws:iam::aws:policy/AmazonS3ReadOnlyAccess --approve
Real-world example
A microservice running inside an EKS pod needs read only access to an S3 bucket, so the team assigns it a dedicated IAM role through IAM Roles for Service Accounts, ensuring other pods in the same cluster cannot access that bucket.
Common follow-ups: What is the difference between node level IAM permissions and IAM Roles for Service Accounts?;How does Kubernetes role based access control work alongside IAM?
IAM;S3 & Storage
How does Kubernetes networking work within an EKS cluster using the Amazon VPC CNI plugin?
Intermediate
The Amazon VPC Container Network Interface plugin assigns each Kubernetes pod its own real IP address directly from your VPC's IP address range, meaning pods can communicate with other AWS resources and be reached using standard VPC networking and security groups, unlike some other Kubernetes networking setups that rely on an overlay network requiring extra translation layers.
kubectl get pods -o wide
Real-world example
A team troubleshooting network connectivity issues in their EKS cluster can directly apply familiar VPC security group rules and flow logs to their pods, since each pod has a real, routable VPC IP address rather than an isolated overlay address.
Common follow-ups: What happens if a subnet runs out of available IP addresses for pods?;How does the VPC CNI plugin compare to other Kubernetes networking plugins?
VPC & Networking;IAM
How do Horizontal Pod Autoscaler and Cluster Autoscaler work together in EKS to handle scaling?
Advanced
The Horizontal Pod Autoscaler automatically adjusts the number of running pod replicas for a workload based on observed metrics like CPU or custom application metrics, while the Cluster Autoscaler monitors whether there is enough underlying node capacity to actually run those pods and automatically adds or removes EC2 instances from the cluster to match demand, meaning the two work together to scale both the application and the infrastructure beneath it.
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
name: web-app
spec:
minReplicas: 2
maxReplicas: 10
metrics:
- type: Resource
resource:
name: cpu
target:
type: Utilization
averageUtilization: 70
Real-world example
An online retailer's EKS cluster automatically scales up both the number of application pods and the number of underlying EC2 worker nodes during a flash sale, then scales both back down afterward, all without manual intervention.
Common follow-ups: What is the difference between the Cluster Autoscaler and Karpenter?;How do you configure custom metrics for the Horizontal Pod Autoscaler?
Auto Scaling Groups;Monitoring (CloudWatch)
What strategies are available for performing zero downtime upgrades of an EKS cluster's Kubernetes version?
Advanced
Upgrading an EKS cluster typically involves first upgrading the managed control plane to the new Kubernetes version, then gradually upgrading the worker nodes, often using a managed node group's rolling update capability or by creating a completely new node group on the newer version and gradually migrating workloads over before removing the old nodes, all designed to avoid dropping application traffic during the transition.
aws eks update-cluster-version --name my-cluster --kubernetes-version 1.29
Real-world example
A platform engineering team upgrades a production EKS cluster by first testing the new Kubernetes version in a staging cluster, then creating a new node group on the updated version in production and slowly draining workloads from the old nodes before decommissioning them.
Common follow-ups: What can go wrong if worker nodes fall too far behind the control plane version?;How do you test an upgrade safely before applying it to production?
AWS CodePipeline
CodeBuild & CodeDeploy (CI/CD);AWS Backup & Disaster Recovery