- name: configure 2nd network interface
  hosts: servers
  become: true

  vars: 
    target_mac: "52:54:00:01:fa:0a"

  tasks:
    - name: ensure nm is running
      service:
        name: NetworkManager
        state: started
        enabled: yes
        
    - name: find interface
      set_fact:  
        the_interface: "{{ item }}"
      when:
        - ansible_facts[item]['macaddress'] is defined
        - ansible_facts[item]['macaddress'] == target_mac
      loop: "{{ ansible_facts['interfaces'] }}"

    - name:
      debug:
        var: the_interface