EKS interview question · Most asked
How do you make workloads on EKS highly available?
Summary
Run nodes in several Availability Zones, run several replicas per service spread across zones (topology spread constraints), use PodDisruptionBudgets, health probes and graceful shutdown, put stateless traffic behind multi-AZ load balancers, and choose multi-AZ data stores (RDS Multi-AZ, Aurora, DynamoDB) rather than single-zone volumes.
Longer Answer
Check the weak spots: single-AZ NAT gateways, cluster add-ons with one replica (CoreDNS, ingress controllers, the load balancer controller), Karpenter or the autoscaler with no capacity in a zone, and EBS-backed StatefulSets pinned to one AZ. For regional failures, consider a second cluster in another Region with DNS failover, which is a much bigger investment.
Key Points
- Multi-AZ nodes and spread replicas.
- PDBs, probes, graceful shutdown.
- Multi-AZ data services.
- No single-AZ add-ons or NAT.
Deep dive: Kubernetes interview questions
More most-asked EKS questions
- What is Amazon EKS, and what does AWS manage versus what do you manage?
- Compare the EKS compute options: managed node groups, self-managed nodes, Fargate, Karpenter and EKS Auto Mode.
- How does the Amazon VPC CNI work, and why do EKS clusters run out of IP addresses?
- IRSA or EKS Pod Identity: how do pods get AWS permissions?
- How do you expose services on EKS? Explain the AWS Load Balancer Controller.
- How do you upgrade an EKS cluster, and what are standard and extended support?
- Why is Karpenter popular on EKS, and how does it differ from the Cluster Autoscaler?
- How do you secure an EKS cluster end to end?