Include Files to Extend Playbook, Register task output, Debug Module

Include Files to Extend Playbook:

Breaks up long playbooks.
Used to add external variable files.
Reuse other playbooks.

tasks:
 - include: wordpress.yml
   vars:
     sitename: My Awesome Site
 - include: loadbalancer.yml
 - include_vars: variables.yml

Example

Register task output:

Grab output of task to another task.

Useful to use tasks to feed data into other tasks.
Useful to create custom error trapping

tasks:
 - shell: /usr/bin/whoami
   register: username
 - file: path=/home/myfile.txt
         owner={{ username }}

Debug Module:

Add debug to tasks.Not same as in -vvv option.
It can receive 2 parameters.
1. msg -- as a message
2. var -- output result as a variable

---

- hosts: centos
  vars: 
   - var_thing: "some message"
  tasks:
   - name: show results
     debug: msg="the variable var_thing is set to - {{ var_thing }}"

---

- hosts: centos
  vars: 
   - var_thing: "some message"
  tasks:
   - name: echo stuff
     command: echo -e "{{ var_thing }} give you up, \n {{ var_thing }} let  you down, \n{{ var_thing }} run around and dessert you"
     register: results
   - name: show results
     debug: msg="{{ results }}"

Instead of complete output of the results, we can just get the portion we want like this, results.stdout_lines

Useful to send output to screen during execution.
Helps find problems

tasks:
 - debug: msg="This host is {{ inventory_hostname }} during execution"
 - shell: /usr/bin/whoami
   register: username
 - debug: var=username