https://github.com/weaveworks/eksctl/issues/19

eksctl-apply.sh

#!/usr/bin/env bash

set -e

if eksctl get cluster -f $FILE >/dev/null 2>&1; then
  # See https://github.com/weaveworks/eksctl/blob/33ec1ed967c1ad03c985bf18774ea970d85c86f1/site/content/usage/03-cluster-upgrade.md#L41
  eksctl update cluster -f $FILE
  eksctl utils update-kube-proxy
  eksctl utils update-aws-node
  eksctl utils update-coredns

  # See https://github.com/weaveworks/eksctl/blob/33ec1ed967c1ad03c985bf18774ea970d85c86f1/site/content/usage/03-cluster-upgrade.md#updating-nodegroups
  eksctl create nodegroup -f $FILE
  
  for nodegroup in $(pending_nodegroups); do
    eksctl utils wait-nodes --nodes-min $NUM_NODES
  done
  
  # TODO: Detect nodegroups to be deleted
  for nodegroup in $(unneeded_nodegroups); do
    # TODO: Drain unneeded nodegroups
    eksctl drain nodegroup -f $FILE --name $nodegroup

    # Delete unneeded nodegroups
    eksctl delete nodegroup -f $FILE --name $nodegroup
  done
else
  eksctl create cluster -f $FILE

  for nodegroup in $(pending_nodegroups); do
    # TODO: Wait until the new nodegroup becomes ready
    eksctl utils wait-nodes --nodes-min $NUM_NODES
  done
fi