---
- name: Check disk space
  hosts: all
  tasks:
    - name: Check free disk space
      shell: df / --output\=avail | tail -1
      register: free
    - name: free-space
      debug:
        msg: Available space = "{{ free.stdout|int / 1000000 }}"
    - fail:
        msg: / is nearly full
      when: free.stdout|int is lt 3000000