Introduction

Variables Overview

• Variables can be found in:
  • Playbooks.
  • Inventory (group var, host var).
  • Command Line.
  • Discovered Variables (facts).

Command Line Var

• To specify an variable in the command line use the option -e "var_name=value". For example:

ansible-playbook playbook_test.yml -e "uservar=me"

Playbook Var

• To reference a variable in playbooks use the var_name format. For example:

---
- name: playbook test of variables
  hosts: routers
  remote_user: "{{ username }}"

....

Inventory

Discovered Facts Var

• Ansible can automatically discover a number of facts about a device. These facts are just variable and can be used in playbooks.
• The use case is to write playbooks that gather information like IP address, version number..etc and reference these variable in the playbook without actually using absolute values.
• To gather facts you'll need to use the setup module with a command like:

ansible-playbook playbook_test.yml -m setup

• Learning facts doesn't work too well for networking devices, but rather for servers. At leas that's the case for now.

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