gistfile1.txt

- name: Check if ballasts exist
  stat: 
    path: "{{ item.path }}/BALLAST"
  loop: "{{ cockroach_db_stores|selectattr('ballast_mb', 'defined')|list }}"
  register: ballasts

- name: Create ballast files
  command: dd if=/dev/zero of={{ item.path }}/BALLAST bs=1M count={{ item.ballast_mb }}
  loop: |
    {% set update=[] %}
    {% for item in ballasts.results %}
    {% if not item.stat.exists or item.stat.size/1048576!=item.item.ballast_mb %}
    {{- update.append(item.item) -}}
    {% endif %}
    {% endfor -%}
    {{ update }}