Unable to access hostvars when the inventory_host is inserted as a variable

Question

I have a jinja2 template, and I'm trying to loop through a host group, and insert the ipv4 address of all the hosts in my template. But I'm getting an error when I do it, even though the way I'm doing it is the way every post and article suggest it should be done.

Here's the template that's producing the error:

{% if groups['linux-hosts'] %}
{% for item in groups['linux-hosts'] %}
define host {
    use                     generic-host-normal
    host_name               {{ item }}
    alias                   {{ item }}
    address                 {{ hostvars[item].ansible_default_ipv4.address }}
}
{% endfor %}
{% endif %}

And the error I'm getting is:

failed: [server] (item=servers.cfg) => {"changed": false, "item": "servers.cfg", "msg": "AnsibleUndefinedVariable: 'ansible.vars.hostvars.HostVarsVars object' has no attribute 'ansible_default_ipv4'"}

If I don't use the variable 'item' in the square brackets, but instead specify a specific host from the inventory, Ansible is able to get the ipv4 address. Example ('server' is the name of a host from my inventory):

{{ hostvars['server'].ansible_default_ipv4.address }}

also, as a friendly FYI, you can shorten that `if` business by just defaulting the groups to empty: `{% for item in groups.get('linux-hosts', []) %}` — mdaniel, Dec 02 '18 at 23:54

score 6 · Answer 1 · answered Sep 25 '19 at 07:49

I came across this problem with a similar use case. My problem turned out to be that I included hosts in a group which were not the target of the play. Therefore gather facts had not run against all the hosts in the group. I fixed this by running setup against all the hosts I needed like this

- name: get cluster facts
  hosts: k8s-cluster
  tags:
    - always
  tasks:
    - name:
      setup:
      become: true

- name: deploy HA Proxy
  hosts: kube-master
  become: yes
  roles:
    - { role: ansible-role-haproxy }

Note: kube-master is a subset of k8s-cluster

score 5 · Accepted Answer · answered Dec 02 '18 at 23:53

5

It's because you are missing the gather_facts: yes or an equivalent - setup: task in your playbook; those facts don't magically appear unless requested, which happens by default, but one can certainly switch off through gather_facts: no

A simple test will show what I mean:

- hosts: all
  gather_facts: yes
  tasks:
  - debug: var=ansible_default_ipv4 verbosity=0

and then change gather_facts: no and observe the kaboom

answered Dec 02 '18 at 23:53

mdaniel

31,240
5
55
58

Thank you! That was indeed the probblem. It turns out that I have another problem too though. I'm now able to get the IP-address of a linux host, but I'm not able to get it from my Windows hosts. When I run a play with only the debug task, like you suggestested, I'm getting this from my windows hosts: ok: [windows1.domain.no] => { "ansible_facts.env.ip_addresses": "VARIABLE IS NOT DEFINED!" } – Harald Dec 03 '18 at 08:28
8

It does not work for me even using ```gather_facts: yes``` – Robert Mar 16 '19 at 06:58

score 0 · Answer 3 · answered Dec 05 '19 at 17:45

0

The solution described here worked for me.

Add an empty play at the top of your playbook to gather facts for all hosts. Ansible hostvars has no attribute 'ansible_nodename'

answered Dec 05 '19 at 17:45

lhc130

9
1

score -1 · Answer 4 · answered Jun 30 '20 at 14:57

-1

I had the same issue.

For me that problem has been that I have run my playbook with the --tags flag.
This lead to the effect that Ansible does not gather any facts!

answered Jun 30 '20 at 14:57

secustor

3,001
2
14
20

Unable to access hostvars when the inventory_host is inserted as a variable

4 Answers4