Ansible Register Variables

Ansible registers provide us with a nice way of capturing the results of a given task and executing a set of additional automations based on the captured results. In many ways, this is similar to variable declarations, although registers are more global in nature. Ansible registers provide us with a way of storing this captured data for later and then conditionalizing future tasks based on the results of previous ones.

Simple Ansible registers

The most basic Ansible register implementations require us to only register the output of a given operation. An example of how to define a simple register is provided next:

---
- name: A Simple Ansible Register Example
  hosts: all
tasks:
- shell: tail -n 100 /etc/motd
register: motd_contents

In this example, we use the register operator to capture the last 100 lines of the system's MOTD file and store it in a global register variable, motd_contents. Ansible registers essentially create a new Ansible fact at runtime, which can...