Karpenter integrates with Amazon Application Recovery Controller for zonal shift support
Amazon EKS now supports ARC zonal shift and zonal autoshift with Karpenter, enhancing Kubernetes application availability by automating traffic redirection from impaired zones. This integration allows for improved recovery and management across AWS Regions and AZs.
Amazon Elastic Kubernetes Service (Amazon EKS) has announced its support for the Amazon Application Recovery Controller (ARC) zonal shift and zonal autoshift, specifically when utilizing the open-source Karpenter project for compute provisioning. ARC is designed to assist in managing and coordinating recovery processes for applications across AWS Regions and Availability Zones (AZs). With this new capability, users can enhance the availability of Kubernetes applications by automating the redirection of in-cluster network traffic away from a compromised AZ.
Many customers deploy highly available applications on Amazon EKS across multiple AZs to mitigate single points of failure. The introduction of ARC zonal shift allows for temporary mitigation of an AZ impairment by rerouting in-cluster network traffic away from the affected zone. For a fully automated experience, users can authorize AWS to handle this process through ARC zonal autoshift, which also includes practice runs to ensure the cluster operates effectively without one AZ.
Once a zonal shift is activated for an EKS cluster, Karpenter ceases the provisioning of new capacity in the impaired AZ and halts voluntary disruptions, such as consolidation and drift, for nodes within that zone. It also prevents voluntary disruptions in unaffected zones that rely on scheduling pods to the compromised zone. Pods with specific scheduling requirements, like volume affinities tied to the impaired zone, will not initiate launch attempts. When the zonal shift concludes or is canceled, Karpenter resumes standard operations.
This feature of Karpenter supports both manual zonal shifts and zonal autoshifts, integrating directly with the existing EKS cluster ARC resource without the need for custom ARC resources. To enable zonal shift support, users should adjust the ENABLE_ZONAL_SHIFT setting in their Karpenter configurations. Further information can be found in the Karpenter and ARC zonal shift documentation.