AWS App Load Balancer for Rancher managed cluster


I have a Rancher 2.3.6 installation that I used to setup an Amazon EC2 cluster (not EKS).
This worked just fine.
The Rancher installation is in one AWS account and the managed cluster is in a different AWS account.
Now I would like to have an AWS application load balancer (ALB) automatically provisioned and maintained in the second AWS account for the managed cluster. The nodes should be automatically added to the ALB if they are replaced in the cluster.
I would maintain my own CNAME entries pointing to this ALB (Route53 is managed in yet another AWS account).

Amazon Cloud Provider was configured for the cluster, the node templates were configures with IAM roles according to this page:

What do I need in order to have the ALB created and maintained automatically?


I am using 2.4.2 and have the same question. Except everything is one account.