build: ensure the justfile could fully replace the makefile.

tests/packer/builds.pkr.hcl

@@ -24,7 +24,7 @@ source "qemu" "default" {
   disk_compression   = true
   disk_detect_zeroes = "unmap"
   disk_discard       = "unmap"
-  output_directory   = pathexpand(var.output)
+  output_directory   = pathexpand(var.output_dir)
   vm_name            = "${local.name}.qcow2"
   boot_wait          = "10s"
   firmware           = pathexpand(var.firmware)
@@ -85,7 +85,7 @@ build {
 
   post-processor "shell-local" {
     inline = [
-      "mv ${var.output}/${local.name}.qcow2 ${var.base_dir}/${local.name}.qcow2",
+      "mv ${var.output_dir}/${local.name}.qcow2 ${var.base_dir}/${local.name}.qcow2",
     ]
   }
 

tests/packer/variables.pkr.hcl

@@ -52,18 +52,18 @@ variable "base_dir" {
   default     = "~/.libvirt/base"
 }
 
+variable "output_dir" {
+  description = "Output build directory"
+  type        = string
+  default     = "~/.libvirt/base/packer"
+}
+
 variable "firmware" {
   description = "Path to the UEFI firmware"
   type        = string
   default     = "/usr/share/edk2/x64/OVMF.4m.fd"
 }
 
-variable "output" {
-  description = "Output build directory"
-  type        = string
-  default     = "/tmp/packer"
-}
-
 variable "prefix" {
   description = "Image name prefix"
   type        = string