AWS Load Balancer Readvertiser

The AWS Load Balancer Readvertiser is a tool that is used for AWS Shoot clusters. The kube-apiserver of a Shoot cluster must be reachable by the kubernetes service in the default namespace (usually created with service ip 100.64.0.1). In order to enable that, the apiserver must expose its public ip address. In the Shoot setup, the only way to reach it is via a public load balancer. However, in AWS you don't get an IP address for your load balancers, but only a hostname. The underlying IP address can change at any time. The detection of those changes is exactly the purpose of the Readvertiser. It will watch for the ELB record changes and update the kubernetes endpoint of the shoot-cluster with the correct IP(s) properly.

Constraints

The kube-apiserver deployment must reside in the same namespace as the Readvertiser has been deployed to.

How to build it?

⚠️ Please don't forget to update the content of the VERSION file before creating a new release:

$ make release

This will build a Go binary, create a new Docker image with the tag you specified in the Makefile, push it to our image registry, and clean up afterwards.

Example manifests

Please find an example Kubernetes manifest within the /example directory.