byo userdata now enabled. refactor some parts into dedicated templates for maintainability

local.tf

@@ -62,29 +62,6 @@ locals {
   asg_tags = ["${null_resource.tags_as_list_of_maps.*.triggers}"]
 
   # More information: https://amazon-eks.s3-us-west-2.amazonaws.com/1.10.3/2018-06-05/amazon-eks-nodegroup.yaml
-  workers_userdata = <<USERDATA
-#!/bin/bash -xe
-
-CA_CERTIFICATE_DIRECTORY=/etc/kubernetes/pki
-CA_CERTIFICATE_FILE_PATH=$CA_CERTIFICATE_DIRECTORY/ca.crt
-mkdir -p $CA_CERTIFICATE_DIRECTORY
-echo "${aws_eks_cluster.this.certificate_authority.0.data}" | base64 -d >  $CA_CERTIFICATE_FILE_PATH
-INTERNAL_IP=$(curl -s http://169.254.169.254/latest/meta-data/local-ipv4)
-sed -i s,MASTER_ENDPOINT,${aws_eks_cluster.this.endpoint},g /var/lib/kubelet/kubeconfig
-sed -i s,CLUSTER_NAME,${var.cluster_name},g /var/lib/kubelet/kubeconfig
-sed -i s,REGION,${data.aws_region.current.name},g /etc/systemd/system/kubelet.service
-sed -i s,MAX_PODS,${lookup(local.max_pod_per_node, var.workers_instance_type)},g /etc/systemd/system/kubelet.service
-sed -i s,MASTER_ENDPOINT,${aws_eks_cluster.this.endpoint},g /etc/systemd/system/kubelet.service
-sed -i s,INTERNAL_IP,$INTERNAL_IP,g /etc/systemd/system/kubelet.service
-DNS_CLUSTER_IP=10.100.0.10
-if [[ $INTERNAL_IP == 10.* ]] ; then DNS_CLUSTER_IP=172.20.0.10; fi
-sed -i s,DNS_CLUSTER_IP,$DNS_CLUSTER_IP,g /etc/systemd/system/kubelet.service
-sed -i s,CERTIFICATE_AUTHORITY_FILE,$CA_CERTIFICATE_FILE_PATH,g /var/lib/kubelet/kubeconfig
-sed -i s,CLIENT_CA_FILE,$CA_CERTIFICATE_FILE_PATH,g  /etc/systemd/system/kubelet.service
-systemctl daemon-reload
-systemctl restart kubelet kube-proxy
-USERDATA
-
   config_map_aws_auth = <<CONFIGMAPAWSAUTH
 apiVersion: v1
 kind: ConfigMap
@@ -101,7 +78,6 @@ data:
 CONFIGMAPAWSAUTH
 
   kubeconfig = <<KUBECONFIG
-
 apiVersion: v1
 clusters:
 - cluster: