I was improving a playbook in Ansible and wanted to find a way to find if a system was virtual or not to decide about some tunning like setting tuned-adm profile virtual-guest or disable the power off when the lid is closed.

After some research and try-except situations I got to this one that seemed to work (I had to tune it as one desktop machine was missing the /sys entry I was using before):

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---
- hosts: all
  user: root
  tasks:
    - name: Check if platform is Virtual
      lineinfile:
        dest: /sys/devices/virtual/dmi/id/sys_vendor
        line: "QEMU"
      check_mode: yes
      register: virtual
      failed_when: (virtual is changed) or (virtual is failed)
      ignore_errors: true

    - name: Check if platform is Physical
      set_fact:
        physical: true
        virtual: false
      when: virtual is changed

    - name: Set fact for Virtual
      set_fact:
        physical: false
        virtual: true
      when: virtual

    - name: Report system is virtual
      debug:
        msg: this is virtual
      when: virtual

    - name: Report system is physical
      debug:
        msg: This is physical
      when: physical

    - name: Get system Chassis
      shell: hostnamectl status | grep Chassis | cut -f2 -d ":" | tr -d ' '
      register: chassis

This playbook tasks check the sys_vendor for QEMU which worked for both systems on real KVM and on some other like Oracle Cloud that provided other values. It uses th lineinfile module that is usually used with a regexp to find a proper value and replace with the one we’re interested in, like in this example I use for setting logrotate.conf settings:

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- name: Configure logrotate.conf
  lineinfile:
    dest: /etc/logrotate.conf
    create: true
    state: present
    regexp: "{{ item.regexp }}"
    line: "{{ item.line }}"
  with_items:
    - { regexp: "^compress", line: "compress" }
    - { regexp: "^rotate.*", line: "rotate 14" }
    - { regexp: "^daily", line: "daily" }
    - { regexp: "^weekly.*", line: "" }
    - { regexp: "^dateext.*", line: "" }

With the first example, we use it in check_mode and use it to setup virtual variable and later we use that to define facts for virtual and physical physical , so that we can decide to use it later in our playbooks like this:

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- name: Set tuned profile for VM's
  shell: /usr/sbin/tuned-adm profile virtual-guest
  when: virtual

- name: Configure systemd for ignoring closed lid on power
  ini_file:
    path: /etc/systemd/logind.conf
    section: Login
    option: HandleLidSwitchExternalPower
    value: ignore
  when: physical and chassis == 'laptop'

- name: Configure systemd for ignoring closed lid on Docked
  ini_file:
    path: /etc/systemd/logind.conf
    section: Login
    option: HandleLidSwitchDocked
    value: ignore
  when: physical and chassis == 'laptop'

Of course, this could also be extended to check if system is really a laptop or different kind of system to enable some other specific tunning, but for some initial tasks, it will do the trick.

Enjoy!

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Pablo Iranzo Gómez Avatar Pablo Iranzo Gómez opensource enthusiast and Lego fan doing some python simple programs like @redken_bot in telegram, etc
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