proxmox-backup/tasks/asserts.yml

---
- name: assert | check OS
  assert:
    that:
      - ansible_distribution == 'Debian'

- name: assert | check vars
  assert:
    that:
      - pbs_user is defined
      - pbs_password is defined
      - pbs_server is defined
      - pbs_datastore is defined
      - pbs_fingerrprint is defined
      - backup_dir is defined
      - backup_local_retention is defined