no idea if this will even work

inventory/host_vars/hulder.yaml

@@ -1,6 +1,6 @@
 ---
 ansible_user: root
-ansible_host: 10.4.0.49
+#ansible_host: 10.4.0.49
 
 base_root_swap_mib: "{{ 1024 * 16 }}"
 base_root_efi_mib: 512

inventory/hosts

@@ -1,5 +1,2 @@
-[all]
-localhost
-
 [base]
 hulder

local.yml

@@ -1,7 +1,6 @@
 ---
 - hosts: all
-  tasks:
-    - name: determine hostname if this is running from archiso
-      debug: msg=hello
+  roles:
+    - detect_archiso 
 
 - import_playbook: playbooks/install.yaml

playbooks/install.yaml

@@ -1,6 +1,11 @@
 ---
-- name: Provision new Arch workstation from scratch
+- name: Check if we appear to be inside an ArchLinux live install environment
   hosts: all
+  roles:
+    - detect_archiso
+
+- name: Provision new Arch workstation from scratch
+  hosts: base
   tags: base
   roles:
     - base

roles/detect_archiso/tasks/main.yaml

@@ -0,0 +1,13 @@
+- name: check for archinstall in path
+  command: which archinstall
+  ignore_errors: true
+  register: which_archinstall
+
+- name: inspect archinstall result
+  set_fact:
+    archiso_detected: "{{ which_archinstall.rc == 0 }}"
+
+- name: override the inventory_hostname
+  set_fact:
+    inventory_hostname: "{{ hostname }}"
+  when: archiso_detected