Generate /etc/hosts with Ansible

main.yml

# Idempotent way to build a /etc/hosts file with Ansible using your Ansible hosts inventory for a source.
# Will include all hosts the playbook is run on.
# Inspired from http://xmeblog.blogspot.com/2013/06/ansible-dynamicaly-update-etchosts.html

- name: "Build hosts file"
  lineinfile: dest=/etc/hosts regexp='.*{{ item }}$' line="{{ hostvars[item]['ansible_default_ipv4']['address'] }} {{item}}" state=present
  when: hostvars[item]['ansible_facts']['default_ipv4'] is defined
  with_items:
  - "{{ groups['all'] }}"

# Debug vars
---
- hosts: '{{ target }}'
  tasks:
  - name: Display all variables/facts known for a host
    debug:
      var: hostvars[inventory_hostname]
      verbosity: 1

• Network bridge in vagrant

---
# filename: debug_vars.yml
# A debug playbook to print all vars
# ansible-playbook -i vagrant.py --limit=special_vm ./debug_vars.yml
# ansible-playbook -i digital_ocean.py --limit=[that_vm|vm_tag] ./debug_vars.yml
- hosts: all
  tasks:
    - name: print out debug info
      debug:
        var: groups

    - name: print out debug info
      debug:
        var: hostvars