Ansible hostvars has no attribute 'ansible_nodename'

Question

We have several playbooks that use hostvars[item]['ansible_nodename'] where item is a host alias. It usually works. But sometimes does not, giving the following error:

'dict object' has no attribute 'ansible_nodename` 

I printed the contents of hostvars and did not see this attribute there.

I could not find the documentation of hostvars to be able to see what we can safely use instead ansible_nodename. So, the questions are:

• Can I safely replace ansible_nodename with ansible_host?
• Where can I find a description of the contents of hostvars and algorithm of its creation?

Answer 1

But sometimes does not, giving the following error...

This can be because facts for those hosts are not gathered at that moment in time.

You may want to add empty play to gather facts for all hosts at the very top of your playbook:

- name: gather facts
  hosts: all

- name: balancer configuration
  hosts: balancer
  tasks:
    - name: generate configs
      template:
        src: conf.j2
        dest: "/conf/{{ hostvars[item]['ansible_nodename'] }}.conf"
      with_hostnames: nodes

Without 'gather facts' play, configuration task for balancer will fail because ansible_nodename is not gathered.