Rename CLC files and favor Terraform list index syntax

* Rename Container Linux Config (CLC) files to *.yaml to align
with Fedora CoreOS Config (FCC) files and for syntax highlighting
* Replace common uses of Terraform `element` (which wraps around)
with `list[index]` syntax to surface index errors

aws/container-linux/kubernetes/ami.tf

@@ -4,8 +4,8 @@ locals {
   # flatcar-stable -> Flatcar Linux AMI
   ami_id = local.flavor == "flatcar" ? data.aws_ami.flatcar.image_id : data.aws_ami.coreos.image_id
 
-  flavor  = element(split("-", var.os_image), 0)
-  channel = element(split("-", var.os_image), 1)
+  flavor  = split("-", var.os_image)[0]
+  channel = split("-", var.os_image)[1]
 }
 
 data "aws_ami" "coreos" {

aws/container-linux/kubernetes/controllers.tf

@@ -10,7 +10,7 @@ resource "aws_route53_record" "etcds" {
   ttl  = 300
 
   # private IPv4 address for etcd
-  records = [element(aws_instance.controllers.*.private_ip, count.index)]
+  records = [aws_instance.controllers.*.private_ip[count.index]]
 }
 
 # Controller instances
@@ -24,7 +24,7 @@ resource "aws_instance" "controllers" {
   instance_type = var.controller_type
 
   ami       = local.ami_id
-  user_data = element(data.ct_config.controller-ignitions.*.rendered, count.index)
+  user_data = data.ct_config.controller-ignitions.*.rendered[count.index]
 
   # storage
   root_block_device {
@@ -36,7 +36,7 @@ resource "aws_instance" "controllers" {
 
   # network
   associate_public_ip_address = true
-  subnet_id                   = element(aws_subnet.public.*.id, count.index)
+  subnet_id                   = aws_subnet.public.*.id[count.index]
   vpc_security_group_ids      = [aws_security_group.controller.id]
 
   lifecycle {
@@ -49,11 +49,8 @@ resource "aws_instance" "controllers" {
 
 # Controller Ignition configs
 data "ct_config" "controller-ignitions" {
-  count = var.controller_count
-  content = element(
-    data.template_file.controller-configs.*.rendered,
-    count.index,
-  )
+  count        = var.controller_count
+  content      = data.template_file.controller-configs.*.rendered[count.index]
   pretty_print = false
   snippets     = var.controller_clc_snippets
 }
@@ -62,7 +59,7 @@ data "ct_config" "controller-ignitions" {
 data "template_file" "controller-configs" {
   count = var.controller_count
 
-  template = file("${path.module}/cl/controller.yaml.tmpl")
+  template = file("${path.module}/cl/controller.yaml")
 
   vars = {
     # Cannot use cyclic dependencies on controllers or their DNS records

aws/container-linux/kubernetes/network.tf

@@ -62,6 +62,6 @@ resource "aws_route_table_association" "public" {
   count = length(data.aws_availability_zones.all.names)
 
   route_table_id = aws_route_table.default.id
-  subnet_id      = element(aws_subnet.public.*.id, count.index)
+  subnet_id      = aws_subnet.public.*.id[count.index]
 }
 

aws/container-linux/kubernetes/nlb.tf

@@ -88,7 +88,7 @@ resource "aws_lb_target_group_attachment" "controllers" {
   count = var.controller_count
 
   target_group_arn = aws_lb_target_group.controllers.arn
-  target_id        = element(aws_instance.controllers.*.id, count.index)
+  target_id        = aws_instance.controllers.*.id[count.index]
   port             = 6443
 }
 

aws/container-linux/kubernetes/ssh.tf

@@ -2,7 +2,7 @@ locals {
   # format assets for distribution
   assets_bundle = [
     # header with the unpack location
-    for key, value in module.bootstrap.assets_dist:
+    for key, value in module.bootstrap.assets_dist :
     format("##### %s\n%s", key, value)
   ]
 }

aws/container-linux/kubernetes/workers/ami.tf

@@ -4,8 +4,8 @@ locals {
   # flatcar-stable -> Flatcar Linux AMI
   ami_id = local.flavor == "flatcar" ? data.aws_ami.flatcar.image_id : data.aws_ami.coreos.image_id
 
-  flavor  = element(split("-", var.os_image), 0)
-  channel = element(split("-", var.os_image), 1)
+  flavor  = split("-", var.os_image)[0]
+  channel = split("-", var.os_image)[1]
 }
 
 data "aws_ami" "coreos" {

aws/container-linux/kubernetes/workers/workers.tf

@@ -78,7 +78,7 @@ data "ct_config" "worker-ignition" {
 
 # Worker Container Linux config
 data "template_file" "worker-config" {
-  template = file("${path.module}/cl/worker.yaml.tmpl")
+  template = file("${path.module}/cl/worker.yaml")
 
   vars = {
     kubeconfig             = indent(10, var.kubeconfig)