Ansible variable

roles-dep1-defaults-main.yml

---
skip_delete: True

roles-dep1-tasks-main.yml

---
- debug: var=skip_delete

- name: delete existing rax instance(s)
  fail: msg='skip_delete is true'
  when: skip_delete

roles-dep2-defaults-main.yml

---
delete_on_start: false

roles-dep2-meta-main.yml

dependencies:
 - { role: dep1, skip_delete: 'not {{delete_on_start}}' }

test.sh

#!/bin/bash

ansible-playbook -i playbooks/inventory -e @playbooks/tower-vars.yml playbooks/test.yml 

test.yml

---
- hosts: local
  roles:
    - { role: dep2 }

vars.yml

---
delete_on_start: true