- name: Create DRO entry
  uri:
    url: "{{ manageiq.api_url }}/api/generic_objects"
    method: POST
    validate_certs: no
    body_format: json
    validate_certs: "{{ manageiq_validate_certs }}"
    user: "{{ manageiq_user }}"
    password: "{{ manageiq_password }}"
    body: "{{ lookup('template','templates/bodydro.j2') }}"
  register: dro


Template

action: create
      name: {{ poolname }}
      generic_object_definition:
        href: {{ manageiq.api_url }}/api/generic_object_definitions/99000000000002
      property_attributes:
        poolname: {{ poolname }}
        vip: {{ vip }}
        {% for i in range(count)%}
  	node{{ i + 1 }}: private_dns_name_list[i]]
        {% endfor %}
        bigipserver: {{ bigip_server }}
      associations:
        service:
          - href: {{ manageiq.api_url }}/api/{{ manageiq.service }}

When running this I get

fatal: [localhost]: FAILED! => {"msg": "An unhandled exception occurred while running the lookup plugin 'template'. Error was a <class 'ansible.errors.AnsibleError'>, original message: Unexpected templating type error occurred on (action: create\n      name: {{poolname}}\n      generic_object_definition:\n        href: {{ manageiq.api_url }}/api/generic_object_definitions/99000000000002\n      property_attributes:\n        poolname: {{ poolname }}\n        vip: {{ vip }}\n        {% for i in range(count)%}\n  \tnode{{ i + 1 }}: private_dns_name_list[i]]\n        {% endfor %}\n        bigipserver: {{ bigip_server }}\n      associations:\n        service:\n          - href: {{ manageiq.api_url }}/api/{{ manageiq.service }}\n): an integer is required"}