Allow the userdata template to be replaced (#565)

* Allow the userdata template to be replaced

* Address fmt issue

* Rename 'customer_userdata' name to 'userdata_template_file'

* Add support for userdata_template_extra_args

* Add support for userdata_template_extra_args

* fix merge conflicts

* Fix merge problem that dropped the file load
Add `platform` to the template expansion context
Add `userdata_launch_template` to `launch_template_userdata`

CHANGELOG.md

@@ -13,6 +13,7 @@ project adheres to [Semantic Versioning](http://semver.org/).
 
 - **Breaking:** Allow for specifying a custom AMI for the worker nodes. (by @bmcstdio)
 - Added support for Windows workers AMIs (by @hodduc)
+- Allow for replacing the full userdata text with a `userdata_template_file` template and `userdata_template_extra_args` in `worker_groups` (by @snstanton)
 - Write your awesome addition here (by @you)
 
 ### Changed

data.tf

@@ -105,13 +105,18 @@ EOF
 
 data "template_file" "userdata" {
   count = local.worker_group_count
-  template = file(
+  template = lookup(
-    lookup(var.worker_groups[count.index], "platform", local.workers_group_defaults["platform"]) == "windows" ?
+    var.worker_groups[count.index],
-    "${path.module}/templates/userdata_windows.tpl" :
+    "userdata_template_file",
-    "${path.module}/templates/userdata.sh.tpl"
+    file(
+      lookup(var.worker_groups[count.index], "platform", local.workers_group_defaults["platform"]) == "windows"
+      ? "${path.module}/templates/userdata_windows.tpl"
+      : "${path.module}/templates/userdata.sh.tpl"
+    )
   )
 
-  vars = {
+  vars = merge({
+    platform            = lookup(var.worker_groups[count.index], "platform", local.workers_group_defaults["platform"])
     cluster_name        = aws_eks_cluster.this.name
     endpoint            = aws_eks_cluster.this.endpoint
     cluster_auth_base64 = aws_eks_cluster.this.certificate_authority[0].data
@@ -135,18 +140,29 @@ data "template_file" "userdata" {
       "kubelet_extra_args",
       local.workers_group_defaults["kubelet_extra_args"],
     )
-  }
+    },
+    lookup(
+      var.worker_groups[count.index],
+      "userdata_template_extra_args",
+      local.workers_group_defaults["userdata_template_extra_args"]
+    )
+  )
 }
 
 data "template_file" "launch_template_userdata" {
   count = local.worker_group_launch_template_count
-  template = file(
+  template = lookup(
-    lookup(var.worker_groups_launch_template[count.index], "platform", local.workers_group_defaults["platform"]) == "windows" ?
+    var.worker_groups_launch_template[count.index],
-    "${path.module}/templates/userdata_windows.tpl" :
+    "userdata_template_file",
-    "${path.module}/templates/userdata.sh.tpl"
+    file(
+      lookup(var.worker_groups_launch_template[count.index], "platform", local.workers_group_defaults["platform"]) == "windows"
+      ? "${path.module}/templates/userdata_windows.tpl"
+      : "${path.module}/templates/userdata.sh.tpl"
+    )
   )
 
-  vars = {
+  vars = merge({
+    platform            = lookup(var.worker_groups_launch_template[count.index], "platform", local.workers_group_defaults["platform"])
     cluster_name        = aws_eks_cluster.this.name
     endpoint            = aws_eks_cluster.this.endpoint
     cluster_auth_base64 = aws_eks_cluster.this.certificate_authority[0].data
@@ -170,7 +186,13 @@ data "template_file" "launch_template_userdata" {
       "kubelet_extra_args",
       local.workers_group_defaults["kubelet_extra_args"],
     )
-  }
+    },
+    lookup(
+      var.worker_groups_launch_template[count.index],
+      "userdata_template_extra_args",
+      local.workers_group_defaults["userdata_template_extra_args"]
+    )
+  )
 }
 
 data "aws_iam_role" "custom_cluster_iam_role" {

local.tf

@@ -40,6 +40,8 @@ locals {
     root_iops                     = "0"                         # The amount of provisioned IOPS. This must be set with a volume_type of "io1".
     key_name                      = ""                          # The key name that should be used for the instances in the autoscaling group
     pre_userdata                  = ""                          # userdata to pre-append to the default userdata.
+    userdata_template_file        = ""                          # alternate template to use for userdata
+    userdata_template_extra_args  = {}                          # Additional arguments to use when expanding the userdata template file
     bootstrap_extra_args          = ""                          # Extra arguments passed to the bootstrap.sh script from the EKS AMI (Amazon Machine Image).
     additional_userdata           = ""                          # userdata to append to the default userdata.
     ebs_optimized                 = true                        # sets whether to use ebs optimization on supported types.