Playbook Variable

About

This article is about variable inside a playbook, task, …

Type

• Single value
• Ansible - List Variable
• Ansible - Dict (Map)
• Ansible - String
• Boolean

logrotate__enabled: True

• Block of text

logrotate__default_options: |
  create
  {{ logrotate__default_period }}
  rotate {{ logrotate__default_rotation }}
  tabooext + .dpkg-divert
  include /etc/logrotate.d

Management

Order of precedence

Order of precedence doc

from least to greatest (

• command line values (eg “-u user”)
• role defaults
• inventory file or script group vars
• inventory group_vars/all
• playbook group_vars/all
• inventory group_vars/*
• playbook group_vars/*
• inventory file or script host vars
• inventory host_vars/*
• playbook host_vars/*
• host facts / cached set_facts
• play vars
• play vars_prompt
• play vars_files
• role vars (defined in role/vars/main.yml)
• block vars (only for tasks in block)
• task vars (only for the task)
• include_vars
• set_facts / registered vars
• role (and include_role) params
• include params
• extra vars (always win precedence)

The order/precedence is (from lowest to highest) on an alphabetical order:

• all group (because it is the ‘parent’ of all other groups)
• parent group
• child group
• host

The merge order for group is done:

• on an alphabetical order (by default)
• of by setting the ansible_group_priority

Example:

• if both groups had the same priority, the result would normally have been testvar == b, but since the a_group has a higher priority, the result is testvar == a

a_group:
    testvar: a
    ansible_group_priority: 10
b_group：
    testvar: b

Init

Hard coded

• In the playbook or a task as an atomic variable with the vars keyword.

- hosts: webservers
  vars:
    http_port: 80

• In the playbook as an Array

vars:
    apache_group: 
      Debian: "root" 
      RedHat: "apache"

Accessed where ansible_os_family is a Ansible - Facts (Remote System Env)

group: "{{ apache_group[ansible_os_family] }}"

• In the playbook as a external File

---
- hosts: all
  remote_user: root
  vars_files:
    - /vars/external_vars.yml

where vars/external_vars.yml format is just a YAML dictionary:

---
somevar: somevalue
password: magic

• At the cli command line with the --extra-vars options

# Key value format
ansible-playbook release.yml --extra-vars "key1=value1 key2=value1 ..."
# Example
ansible-playbook release.yml --extra-vars "version=1.23.45 other_variable=foo"
# Json format
ansible-playbook release.yml --extra-vars '{"version":"1.23.45","other_variable":"foo"}'
ansible-playbook release.yml --extra-vars "@some_file.json"
ansible-playbook arcade.yml --extra-vars "{\"name\":\"Conan O\'Brien\"}" # With escaping

Env variable

env variable

{{ lookup('env', 'MY_USER') | default('admin', true) }}

Built-in

All ansible_... variable

• Facts are information derived from speaking with your remote systems. You can find a complete set under the ansible_facts variable.
• magic
• connection variable

include_vars

In a role where you have a vars directory with include_vars

- name: Include version-specific variables for CentOS/RHEL.
  include_vars: "RedHat-{{ ansible_distribution_version.split('.')[0] }}.yml"
  when: ansible_distribution == 'CentOS' or
        ansible_distribution == 'Red Hat Enterprise Linux' or
        ansible_distribution == 'RedHat'

set_facts

- name: Define java_packages.
  set_fact:
    java_packages: "{{ __java_packages | list }}"
  when: java_packages is not defined

from shell

You can register the output of a shell and use it as a variable.

See Ansible - Shell

Properties

Mandatory

{{ variable | mandatory }}

default value

• numeric

{{ some_variable | default(5) }}

• String

{{ some_variable | default('default_value') }}

defined/undefined

when: foo is defined
when: bar is undefined

Scope

• On a group level
• On a host level

Configuration

hash_merge

By default, Ansible overwrites variables including the ones defined for a group and/or host.

see the hash_merge setting.

Print

You can print the variable with the debug task

Example:

• in a playbook

- debug: msg="{{ streaming_jar_path_result.files[0].path }}"

• at the comand line with the ansible command line Example to get the ansible_host value

ansible -i inventory.yml -m debug -a var=ansible_host all

vps | SUCCESS => {
    "ansible_host": "server01.example.com"
}

Support

template error while templating string: unexpected char u

fatal: [primary_gateway_dev131]: FAILED! => {"msg": "template error while templating string: unexpected char u's' at 7. String: {{ 1022sp1_file_base }}"}

variable should not start with a number

Documentation / Reference

* https://docs.ansible.com/ansible/latest/user_guide/playbooks_variables.html