Ansible - Facts

Facts:

• Usually gathered by the setup module
• All facts are in this var: ansible_facts
• Some facts are injected as top level variables starting with ansible_

Show all facts available:

- debug: var=ansible_facts

See raw gathered info:

ansible hostname -m setup

Hostname as reported by the system:

{{ ansible_facts['nodename'] }}

Disable facts gathering ( probably faster ):

- hosts: whatever
  gather_facts: no
  tasks:
    ....

Some common facts:

  tasks:
    - debug: var=ansible_facts['distribution']
    - debug: var=ansible_facts['distribution_major_version']
    - debug: var=ansible_facts['os_family']
    - debug: var=ansible_facts['all_ipv4_addresses']
    - debug: var=ansible_facts['default_ipv4']
    - debug: var=ansible_facts['env']
    - debug: var=ansible_facts['hostname']
    - debug: var=ansible_facts['interfaces']
    - debug: var=ansible_facts['kernel']

Facts from Other Hosts

Access fact from other host:

{{ hostvars['asdf.example.com']['ansible_facts']['os_family'] }}

For this to work, need to:

• Enable fact caching
• Access the other host previously in the playbook

Example using jsonfile:

ansible.cfg

[defaults]
gathering = smart
fact_caching = jsonfile
fact_caching_connection = /path/to/cachedir
fact_caching_timeout = 86400
# seconds

• “To benefit from cached facts, you will want to change the gathering setting to smart or explicit or set gather_facts to False in most plays.”
• Cache plugins: redis or jsonfile
• fact_caching_timeout - how long to cache the facts

Custom Defined - facts.d

• fact_path - can be set for alternate path

Facts can also be supplied by files that:

• are in /etc/ansible/facts.d
• end in ‘.fact’
• are JSON, INI, or executable returning JSON

Example hash variable:

/etc/ansible/facts.d/preferences.fact
[general]
asdf=1
bar=2

Check it:

ansible host1 -m setup -a "filter=ansible_local"


"ansible_local": {
        "preferences": {
            "general": {
                "asdf" : "1",
                "bar"  : "2"
            }
        }
 }

Use stuff from facts.d like this:

{{ ansible_local['preferences']['general']['asdf'] }}