EKS Auto Mode hands node provisioning, core add-ons, load balancing and block storage to AWS. We moved two clusters from managed node groups and self-managed Karpenter. What Auto Mode manages, what changes for operators, the limits that surprised us, and the migration steps that kept workloads running.
We moved CI to self-hosted GitHub Actions runners on EKS with Actions Runner Controller. Every job that built an image failed: Cannot connect to the Docker daemon. Runner pods have no Docker by default. How dind and kubernetes container modes work, what each costs in security, and the node pool we gave them.
We moved our EKS batch node pool to Spot and cut its cost by 60 percent. Within a week, nightly jobs failed most nights: a single instance type, no interruption handling and jobs with no checkpoints. Diversified instances, graceful draining and checkpointing made Spot reliable.
After upgrading to Karpenter v1 with WhenEmptyOrUnderutilized consolidation, our EKS cluster replaced nodes constantly and long-running pods were evicted every few minutes. How we read Karpenter's events, tuned consolidateAfter and disruption budgets, and protected jobs that must not be interrupted.