ansible magic variables not returning values - ansible

Question

I'm trying to build a /etc/hosts file; however it seems that I can't get the hostvars to show up when running a playbook, but with the command line it works to a point.
Here is my ansible.cfg file:
[defaults]
ansible_managed = Please do not change this file directly since it is managed by Ansible and will be overwritten
library = ./library
module_utils = ./module_utils
action_plugins = plugins/actions
callback_plugins = plugins/callback
filter_plugins = plugins/filter
roles_path = ./roles
# Be sure the user running Ansible has permissions on the logfile
log_path = $HOME/ansible/ansible.log
inventory = hosts
forks = 20
host_key_checking = False
gathering = smart
fact_caching = jsonfile
fact_caching_connection = $HOME/ansible/facts
fact_caching_timeout = 7200
nocows = 1
callback_whitelist = profile_tasks
stdout_callback = yaml
force_valid_group_names = ignore
inject_facts_as_vars = False
# Disable them in the context of https://review.openstack.org/#/c/469644
retry_files_enabled = False
# This is the default SSH timeout to use on connection attempts
# CI slaves are slow so by setting a higher value we can avoid the following error:
# Timeout (12s) waiting for privilege escalation prompt:
timeout = 60
[ssh_connection]
# see: https://github.com/ansible/ansible/issues/11536
control_path = %(directory)s/%%h-%%r-%%p
ssh_args = -o ControlMaster=auto -o ControlPersist=600s
pipelining = True
# Option to retry failed ssh executions if the failure is encountered in ssh itself
retries = 10
Here is my playbook:
- name: host file update
hosts: baremetal
become: true
gather_facts: true
vars:
primarydomain: "cephcluster.local"
tasks:
- name: print ipv4 info
debug:
msg: "IPv4 addresses: {{ansible_default_ipv4.address }}"
- name: update host file
lineinfile:
dest: /etc/hosts
regexp: '{{ hostvars[item].ansible_default_ipv4.address }}.*{{ item }} {{item}}.{{primarydomain}}$'
line: "{{ hostvars[item].ansible_default_ipv4.address }} {{item}} {{item}}.{{primarydomain}}"
state: present
with_items: "{{ groups.baremetal }}"
Here is my inventory file:
[baremetal]
svr1 ansible_host=192.168.59.10
svr2 ansible_host=192.168.59.11
svr3 ansible_host=192.168.59.12
When I run the playbook I get:
FAILED! =>
msg: |-
The task includes an option with an undefined variable. The error was: 'ansible_default_ipv4' is undefined
However when I run
ansible baremetal -m gather_facts -a "filter=ansible_default_ipv4"
I get:
| SUCCESS => {
"ansible_facts": {
"ansible_default_ipv4": {
"address": "192.168.59.20",
"alias": "eno1",
"broadcast": "192.168.59.255",
"gateway": "192.168.59.1",
"interface": "eno1",
"macaddress": "80:18:44:e0:4b:a4",
"mtu": 1500,
"netmask": "255.255.255.0",
"network": "192.168.59.0",
"type": "ether"
}
},
"changed": false,
"deprecations": [],
"warnings": []
}
But; if I run
ansible baremetal -m gather_facts -a "filter=ansible_default_ipv4.address"
I get nothing in the return:
SUCCESS => {
"ansible_facts": {},
"changed": false,
"deprecations": [],
"warnings": []
}
I have even tried in the playbook:
- debug:
msg: "IPv4 addresses: {{ansible_default_ipv4 }}"
and nothing gets returned.
Not sure what I'm missing.

Answer 1

You should get used to use and abuse the debug module.
Provided that the ansible ad-hoc command raised you that the facts are under ansible_facts, you could have done a simple task in your playbook:
- debug:
var: ansible_facts
From that, you would have discovered that the fact you are looking for is nested in the dictionary ansible_facts under the key default_ipv4. And that you can access its address with the property address.
So, your debug task ends up being:
- debug:
msg: "IPv4 addresses: {{ ansible_facts.default_ipv4.address }}"