Ansible troubleshooting - VARIABLE IS NOT DEFINED! ansible_hostname
Root cause analysis when the variable is not misspelled or not defined using the ansible_hostname internal variable and gather_facts boolean.
Today we’re going to talk about Ansible troubleshooting, specifically about VARIABLE IS NOT DEFINED! Message.
Most of the time the root cause is a misspelled variable or a variable really not defined. This use case is special about the ansible_hostname internal variable.
I’m Luca Berton and welcome to today’s episode of Ansible Pilot.
The Best Resources For Ansible
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Books
- Ansible For VMware by Examples: A Step-by-Step Guide to Automating Your VMware Infrastructure
- Ansible by Examples: 200+ Automation Examples For Linux and Windows System Administrator and DevOps
- Ansible For Windows By Examples: 50+ Automation Examples For Windows System Administrator And DevOps
- Ansible For Linux by Examples: 100+ Automation Examples For Linux System Administrator and DevOps
- Ansible Linux Filesystem By Examples: 40+ Automation Examples on Linux File and Directory Operation for Modern IT Infrastructure
- Ansible For Containers and Kubernetes By Examples: 20+ Automation Examples To Automate Containers, Kubernetes and OpenShift
- Ansible For Security by Examples: 100+ Automation Examples to Automate Security and Verify Compliance for IT Modern Infrastructure
- Ansible Tips and Tricks: 10+ Ansible Examples to Save Time and Automate More Tasks
- Ansible Linux Users & Groups By Examples: 20+ Automation Examples on Linux Users and Groups Operation for Modern IT Infrastructure
- Ansible For PostgreSQL by Examples: 10+ Examples To Automate Your PostgreSQL database
- Ansible For Amazon Web Services AWS By Examples: 10+ Examples To Automate Your AWS Modern Infrastructure
demo
The best way of talking about Ansible troubleshooting is to jump in a live demo to show you practically the VARIABLE IS NOT DEFINED! and how to solve it!
error code
---
- name: hostname demo
hosts: all
gather_facts: false
tasks:
- name: print hostname
ansible.builtin.debug:
var: ansible_hostname
error execution
ansible-pilot $ ansible-playbook -i virtualmachines/demo/inventory troubleshooting/variablenotdefined_error.yml
PLAY [hostname demo] ******************************************************************************
TASK [print hostname] *****************************************************************************
ok: [demo.example.com] => {
"ansible_hostname": "VARIABLE IS NOT DEFINED!"
}
PLAY RECAP ****************************************************************************************
demo.example.com : ok=1 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
ansible-pilot $
fix code
---
- name: hostname demo
hosts: all
gather_facts: true
tasks:
- name: print hostname
ansible.builtin.debug:
var: ansible_hostname
fix execution
ansible-pilot $ ansible-playbook -i virtualmachines/demo/inventory troubleshooting/variablenotdefined_fix.yml
PLAY [hostname demo] ******************************************************************************
TASK [Gathering Facts] ****************************************************************************
ok: [demo.example.com]
TASK [print hostname] *****************************************************************************
ok: [demo.example.com] => {
"ansible_hostname": "demo"
}
PLAY RECAP ****************************************************************************************
demo.example.com : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
ansible-pilot $
Recap
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