Update Matchbox profile to use initramfs and rootfs images

* Fedora CoreOS stable (after Oct 6) ships separate initramfs
and rootfs images, used as initrd's
* Update profiles to match the Matchbox examples, which have
already switched to the new profile and to remove the unused
kernel args
* Requires Fedora CoreOS version which ships rootfs images
(e.g. stable 32.20200923.3.0 or later)

Rel:

* coreos/fedora-coreos-tracker#390 (comment)
* poseidon/matchbox@da0df01#diff-4541f7b7c174f6ae6270135942c1c65ed9e09ebe81239709f5a9fb34e858ddcf

Supercedes poseidon#888

fedora-coreos/kubernetes/profiles.tf

@@ -1,26 +1,32 @@
 locals {
   remote_kernel = "https://builds.coreos.fedoraproject.org/prod/streams/${var.os_stream}/builds/${var.os_version}/x86_64/fedora-coreos-${var.os_version}-live-kernel-x86_64"
-  remote_initrd = "https://builds.coreos.fedoraproject.org/prod/streams/${var.os_stream}/builds/${var.os_version}/x86_64/fedora-coreos-${var.os_version}-live-initramfs.x86_64.img"
+  remote_initrd = [
+    "https://builds.coreos.fedoraproject.org/prod/streams/${var.os_stream}/builds/${var.os_version}/x86_64/fedora-coreos-${var.os_version}-live-initramfs.x86_64.img",
+    "https://builds.coreos.fedoraproject.org/prod/streams/${var.os_stream}/builds/${var.os_version}/x86_64/fedora-coreos-${var.os_version}-live-rootfs.x86_64.img"
+  ]
+
   remote_args = [
     "ip=dhcp",
     "rd.neednet=1",
-    "initrd=fedora-coreos-${var.os_version}-live-initramfs.x86_64.img",
-    "coreos.inst.image_url=https://builds.coreos.fedoraproject.org/prod/streams/${var.os_stream}/builds/${var.os_version}/x86_64/fedora-coreos-${var.os_version}-metal.x86_64.raw.xz",
-    "coreos.inst.ignition_url=${var.matchbox_http_endpoint}/ignition?uuid=$${uuid}&mac=$${mac:hexhyp}",
     "coreos.inst.install_dev=${var.install_disk}",
+    "coreos.inst.ignition_url=${var.matchbox_http_endpoint}/ignition?uuid=$${uuid}&mac=$${mac:hexhyp}",
+    "coreos.inst.image_url=https://builds.coreos.fedoraproject.org/prod/streams/${var.os_stream}/builds/${var.os_version}/x86_64/fedora-coreos-${var.os_version}-metal.x86_64.raw.xz",
     "console=tty0",
     "console=ttyS0",
   ]
 
   cached_kernel = "/assets/fedora-coreos/fedora-coreos-${var.os_version}-live-kernel-x86_64"
-  cached_initrd = "/assets/fedora-coreos/fedora-coreos-${var.os_version}-live-initramfs.x86_64.img"
+  cached_initrd = [
+    "/assets/fedora-coreos/fedora-coreos-${var.os_version}-live-initramfs.x86_64.img",
+    "/assets/fedora-coreos/fedora-coreos-${var.os_version}-live-rootfs.x86_64.img"
+  ]
+
   cached_args = [
     "ip=dhcp",
     "rd.neednet=1",
-    "initrd=fedora-coreos-${var.os_version}-live-initramfs.x86_64.img",
-    "coreos.inst.image_url=${var.matchbox_http_endpoint}/assets/fedora-coreos/fedora-coreos-${var.os_version}-metal.x86_64.raw.xz",
-    "coreos.inst.ignition_url=${var.matchbox_http_endpoint}/ignition?uuid=$${uuid}&mac=$${mac:hexhyp}",
     "coreos.inst.install_dev=${var.install_disk}",
+    "coreos.inst.ignition_url=${var.matchbox_http_endpoint}/ignition?uuid=$${uuid}&mac=$${mac:hexhyp}",
+    "coreos.inst.image_url=${var.matchbox_http_endpoint}/assets/fedora-coreos/fedora-coreos-${var.os_version}-metal.x86_64.raw.xz",
     "console=tty0",
     "console=ttyS0",
   ]
@@ -37,9 +43,7 @@ resource "matchbox_profile" "controllers" {
   name  = format("%s-controller-%s", var.cluster_name, var.controllers.*.name[count.index])
 
   kernel = local.kernel
-  initrd = [
-    local.initrd
-  ]
+  initrd = local.initrd
   args = concat(local.args, var.kernel_args)
 
   raw_ignition = data.ct_config.controller-ignitions.*.rendered[count.index]
@@ -73,9 +77,7 @@ resource "matchbox_profile" "workers" {
   name  = format("%s-worker-%s", var.cluster_name, var.workers.*.name[count.index])
 
   kernel = local.kernel
-  initrd = [
-    local.initrd
-  ]
+  initrd = local.initrd
   args = concat(local.args, var.kernel_args)
 
   raw_ignition = data.ct_config.worker-ignitions.*.rendered[count.index]