Use CIDATA seed for EL/Amazon/SUSE guests (fixes EL8 boot/SSH)

internal/vm/qemu.go

@@ -675,16 +675,32 @@ func normalizeArch(arch string) string {
 	}
 }
 
+// needsCIDATASeed reports whether a profile's distro needs the cloud-init seed
+// delivered as a CIDATA-labelled disk/ISO rather than the NoCloud-over-SMBIOS
+// network seed (the Ubuntu/Debian default). EL (RHEL/AlmaLinux/Rocky/CentOS/
+// Oracle), Amazon Linux, and SUSE cloud-init configs do not reliably honour the
+// SMBIOS-net seed: on EL8 cloud-init falls back to DataSourceNone and never
+// authorises the injected SSH key (observed booting AlmaLinux/Rocky 8). Those
+// images do read a CIDATA disk/ConfigDrive, so use that instead.
+func needsCIDATASeed(profile Profile) bool {
+	switch strings.ToLower(strings.TrimSpace(profile.Distro)) {
+	case "rhel", "almalinux", "rocky", "centos", "centos-stream",
+		"oracle", "oracle-linux", "amazon-linux", "amazonlinux",
+		"sles", "suse", "opensuse":
+		return true
+	}
+	// Keep the explicit ID for any profile that omits a recognised distro.
+	return strings.EqualFold(strings.TrimSpace(profile.ID), "rhel-8-4.18")
+}
+
 func seedDeliveryForProfile(profile Profile) seedDeliveryMode {
-	switch strings.ToLower(strings.TrimSpace(profile.ID)) {
-	case "rhel-8-4.18":
+	if needsCIDATASeed(profile) {
 		if commandAvailable("cloud-localds") {
 			return seedDeliveryNoCloudConfigDrive
 		}
 		return seedDeliveryNoCloudConfigFS
-	default:
-		return seedDeliveryNoCloudNet
 	}
+	return seedDeliveryNoCloudNet
 }
 
 func commandAvailable(name string) bool {

internal/vm/qemu_test.go

@@ -378,9 +378,20 @@ func TestSeedDeliveryForProfile(t *testing.T) {
 	if got := seedDeliveryForProfile(Profile{ID: "rhel-8-4.18"}); got != seedDeliveryNoCloudConfigDrive && got != seedDeliveryNoCloudConfigFS {
 		t.Fatalf("expected rhel-8-4.18 seed delivery %q or %q, got %q", seedDeliveryNoCloudConfigDrive, seedDeliveryNoCloudConfigFS, got)
 	}
-	if got := seedDeliveryForProfile(Profile{ID: "ubuntu-22.04-5.15"}); got != seedDeliveryNoCloudNet {
+	if got := seedDeliveryForProfile(Profile{ID: "ubuntu-22.04-5.15", Distro: "ubuntu"}); got != seedDeliveryNoCloudNet {
 		t.Fatalf("expected default seed delivery %q, got %q", seedDeliveryNoCloudNet, got)
 	}
+	if got := seedDeliveryForProfile(Profile{ID: "debian-12-6.1", Distro: "debian"}); got != seedDeliveryNoCloudNet {
+		t.Fatalf("expected debian seed delivery %q, got %q", seedDeliveryNoCloudNet, got)
+	}
+	// EL-family / Amazon / SUSE must use the CIDATA disk seed (SMBIOS-net is
+	// ignored by their cloud-init).
+	for _, distro := range []string{"almalinux", "rocky", "rhel", "centos-stream", "oracle", "amazon-linux", "sles", "opensuse"} {
+		got := seedDeliveryForProfile(Profile{ID: distro + "-x", Distro: distro})
+		if got != seedDeliveryNoCloudConfigDrive && got != seedDeliveryNoCloudConfigFS {
+			t.Fatalf("expected CIDATA seed for distro %q, got %q", distro, got)
+		}
+	}
 }
 
 func TestMapFixupArgs(t *testing.T) {

scripts/hetzner-bootstrap-vm.sh

@@ -47,7 +47,12 @@ sudo apt-get update -y
 sudo apt-get install -y \
   build-essential ca-certificates curl git jq make pkg-config \
   clang llvm libbpf-dev libelf-dev zlib1g-dev zstd \
-  qemu-system-x86 qemu-utils qemu-kvm openssh-client
+  qemu-system-x86 qemu-utils qemu-kvm openssh-client \
+  cloud-image-utils
+# cloud-image-utils provides cloud-localds, used to build a CIDATA ConfigDrive
+# ISO seed for EL/Amazon/SUSE guests whose cloud-init ignores the SMBIOS-net
+# seed (see internal/vm seedDeliveryForProfile). Without it those guests fall
+# back to an unreliable vvfat seed and fail to boot.
 
 # bpfcompat requires Go ${GO_VERSION}; Ubuntu's apt golang is too old, so install
 # the official toolchain to /usr/local/go and symlink it onto the default PATH