site.yml

---
- name: generate temporary files
  hosts: all
  gather_facts: no

  tasks:
    - name: setup the variable to dump
      set_fact:
        output_var:
          hostname: "{{ inventory_hostname }}"
          ok_count: "{{ 10 | random }}"
          ng_count: "{{ 10 | random }}"

    - name: dump the variable to a local file
      copy:
        content: "{{ output_var | to_nice_json }}"
        dest: "/var/tmp/test_{{ inventory_hostname }}.json"
        force: yes
      delegate_to: localhost

- name: aggregate temporary files
  hosts: localhost
  gather_facts: no
  vars:
    total_ok: 0
    total_ng: 0

  tasks:
    - name: read and count the variables in all .json files
      include_tasks:
        file: loopblock.yml
      with_fileglob:
        - "/var/tmp/test_*.json"

    - name: print total counts
      debug:
        msg: "Total OKs = {{ total_ok }}, Total NGs = {{ total_ng }}"