---
- name: Get MAC address of default physical interface
  hosts: all
  gather_facts: yes
  tasks:

    - name: Set default interface
      set_fact:
        default_iface: "{{ ansible_facts.default_ipv4.interface | default('') }}"

    - name: Set primary MAC address if available
      set_fact:
        primary_physical_iface: "{{ default_iface }}"
        primary_mac: "{{ ansible_facts['ansible_' + default_iface]['macaddress'] }}"
      when: default_iface != '' and ('ansible_' + default_iface) in ansible_facts

    - name: Show MAC address
      debug:
        msg: >-
          MAC address of primary physical interface ({{ primary_physical_iface }}):
          {{ primary_mac | default('Not found') }}