The traditional method of provisioning load balancers directly from clusters in Kubernetes may not always align with the application architecture, leading to a need for an alternative mechanism. TargetGroupBinding, a custom resource in Kubernetes, allows users to route traffic from existing clusters to services without the need to provision new load balancers. This approach supports decoupling load balancer creation and deletion from the lifecycle of services and ingress resources, enabling users to abstract and decouple load balancers from native Kubernetes resources. TargetGroupBinding supports instance or IP target groups and can be used for explicit provisioning and management of load balancer infrastructure, providing a dynamic solution for routing traffic to services.
Different use cases and architectural patterns may require managing load balancer lifecycles outside of native Kubernetes resources. TargetGroupBinding can be utilized to maintain dynamic configurations for load balancer infrastructure. For global load balancing solutions with AWS Global Accelerator, users can bind AWS Global Accelerator, load balancers, and externally managed Kubernetes services together using TargetGroupBinding. This approach allows for the provisioning of AWS Global Accelerator, load balancers, and Kubernetes services with Infrastructure as Code tools, dynamically associating the load balancer’s target group with Amazon EKS.
Users may need to configure an NLB in front of an ALB to share a single endpoint for L4 and L7 requests. TargetGroupBinding offers the functionality to have a static or predefined load balancing configuration and dynamically register pods as targets. Blue/Green cluster updates can be achieved by creating a new EKS cluster and using TargetGroupBinding to associate it with existing load balancers, enabling blue/green upgrade strategies with minimal downtime. Hybrid implementations, where EKS-based applications run in parallel with non-EKS-based applications, can also benefit from TargetGroupBinding to route traffic to different clusters using the same load balancer.
In summary, TargetGroupBinding provides a flexible approach to managing load balancer configurations in Kubernetes, allowing for dynamic associations between services and load balancers outside of the Kubernetes environment. It is essential for users to consider the best architecture for their applications and weigh the pros and cons of different routing configurations. For detailed information on utilizing ALBs and TargetGroupBinding, refer to the documentation.
Article Source
https://aws.amazon.com/blogs/containers/patterns-for-targetgroupbinding-with-aws-load-balancer-controller/