What is the AWS Load Balancer Controller, and what does it provision?
AWS · Intermediate level
Answer
The AWS Load Balancer Controller watches Kubernetes Ingress and Service resources and provisions AWS ALBs or NLBs. It lets teams declare load-balancing through Kubernetes manifests while AWS resources are reconciled automatically.
Technical explanation
The controller needs scoped AWS IAM permissions, usually through workload identity, because it creates AWS load balancer resources.
EKS is managed Kubernetes, not no-ops Kubernetes: IAM, networking, add-ons, node strategy, upgrades, RBAC, policies, and workload reliability remain customer responsibilities.
Workload identity, private networking, image security, ingress standards, autoscaling, and observability are foundational controls for production clusters.
Troubleshooting EKS requires separating control-plane, node, CNI, scheduler, ingress, and application failure domains.
Hands-on example
1. Create or use an EKS sandbox cluster with private subnets, managed add-ons, workload IAM, and a sample namespace.
2. Deploy a small container from ECR using Kubernetes manifests or Helm, with readiness/liveness probes and resource requests.
3. Add ingress/load balancing, pod IAM, logging, metrics, and network/security controls relevant to the question.
4. Test node replacement, pod rescheduling, image pulls, access control, and rollback.
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