Ansible variables and facts

Variables

#

Example in a playbooks:

- hosts: all
  vars:
    foo: bar

Example in a playbooks for external file:

- hosts: all
  vars_files:
    - vars/common.yml

Example in inventory:

[lala]
server1

[lala:vars]
user=joe

• the directories group_vars and host_vars in the same directory as the inventory file or directory are implicitly sourced.
• bracket notation is preferred above dot notation to avoid confusion to methods or attributes.

animal:
  pike:
    class: fish
    legs: no
  wolf:
    class: canine
    legs: yes

animal.pike.class --> 'fish'

better: animal['pike']['class']

Facts

#

Disable the use of facts

#

Example:

---
- name: 
  gather_facts: no
...

# ansible 10.0.0.90 -m setup -a 'filter=ansible_fqdn'
10.0.0.90 | SUCCESS => {
    "ansible_facts": {
        "ansible_fqdn": "heimdall.doubtfull.snd"
    }, 
    "changed": false
}

Add facts to a system

#

File /etc/ansible/facts.d/system.fact

[system_responsiblity]
gateway = true

# ansible 10.0.0.170 -m setup -a 'filter=ansible_local'
10.0.0.170 | SUCCESS => {
    "ansible_facts": {
        "ansible_local": {
            "system": {
                "system_responsiblity": {
                    "gateway": "true"
                }
            }
        }
    }, 
    "changed": false
}

Query based on fact

#

# ansible webserver -m setup -a 'filter=ansible_user*'
servera.lab.example.com | SUCCESS => {
    "ansible_facts": {
        "ansible_user_dir": "/root", 
        "ansible_user_gecos": "root", 
        "ansible_user_gid": 0, 
        "ansible_user_id": "root", 
        "ansible_user_shell": "/bin/bash", 
        "ansible_user_uid": 0, 
        "ansible_userspace_architecture": "x86_64", 
        "ansible_userspace_bits": "64"
    }, 
    "changed": false
}