Allow setting custom PXE boot kernel_args on bare-metal

bare-metal/container-linux/kubernetes/profiles.tf

@@ -12,6 +12,7 @@ resource "matchbox_profile" "container-linux-install" {
     "coreos.first_boot=yes",
     "console=tty0",
     "console=ttyS0",
+    "${var.kernel_args}",
   ]
 
   container_linux_config = "${data.template_file.container-linux-install-config.rendered}"
@@ -47,6 +48,7 @@ resource "matchbox_profile" "cached-container-linux-install" {
     "coreos.first_boot=yes",
     "console=tty0",
     "console=ttyS0",
+    "${var.kernel_args}",
   ]
 
   container_linux_config = "${data.template_file.cached-container-linux-install-config.rendered}"

bare-metal/container-linux/kubernetes/variables.tf

@@ -109,3 +109,9 @@ variable "container_linux_oem" {
   default     = ""
   description = "Specify an OEM image id to use as base for the installation (e.g. ami, vmware_raw, xen) or leave blank for the default image"
 }
+
+variable "kernel_args" {
+  description = "Additional kernel arguments the servers should boot with."
+  type        = "list"
+  default     = []
+}

bare-metal/container-linux/pxe-worker/profiles.tf

@@ -8,12 +8,11 @@ resource "matchbox_profile" "bootkube-worker-pxe" {
   ]
 
   args = [
-    "root=/dev/sda1",
     "coreos.config.url=${var.matchbox_http_endpoint}/ignition?uuid=$${uuid}&mac=$${mac:hexhyp}",
     "coreos.first_boot=yes",
     "console=tty0",
     "console=ttyS0",
-    "kvm-intel.nested=1",
+    "${var.kernel_args}",
   ]
 
   container_linux_config = "${file("${path.module}/cl/bootkube-worker.yaml.tmpl")}"

bare-metal/container-linux/pxe-worker/variables.tf

@@ -53,3 +53,14 @@ variable "kube_dns_service_ip" {
   type        = "string"
   default     = "10.3.0.10"
 }
+
+# optional
+
+variable "kernel_args" {
+  description = "Additional kernel arguments the server should boot with."
+  type        = "list"
+
+  default = [
+    "root=/dev/sda1",
+  ]
+}