Context in weaveworks/eksctl#3231 (review)

PR o'clock

Description

Resolves #774

The change is intended to improve the ability to manage worker groups using maps. Which should allow to more flexibly add/remove worker groups (improve this: https://github.com/terraform-aws-modules/terraform-aws-eks/blob/master/docs/faq.md#how-do-i-safely-remove-old-worker-groups).

The change includes suggested in #774 changes which include:

The logs in info mode should state the reason for cordoning/termination.

Is this a BUG REPORT or FEATURE REQUEST?: Bug Report

What happened: Running go run ./main.go with KUBECONFIG=/Users/scole/.kube/config:/Users/scole/.kube/config-apptio-clusters:/Users/scole/.kube/config-eks causes the startup to fail.

2020-10-29T10:19:12.506+1100	INFO	controller-runtime.metrics	metrics server is starting to listen	{"addr": ":8080"}
2020-10-29T10:19:12.506+1

There should be a way to get a kubeconfig for eks clusters that already exist.

Similar to this PR for GCP: https://gist.github.com/geekflyer/b78adab2667d8526a1dd593bc5c844bf#file-gke-ts-L33-L66