Ansible Conditionals

External

• https://docs.ansible.com/ansible/latest/user_guide/playbooks_conditionals.html
• https://docs.ansible.com/ansible/latest/user_guide/playbooks_conditionals.html#loops-and-conditionals

Internal

• Ansible Concepts

Overview

Tasks can be conditionally executed based on facts, registered variables or playbook or inventory variables. The conditional is introduced by the task configuration keyword when:.

The variables must not be enclosed in Template:... when used in when: expressions.

- name: Download Amazon Corretto
  get_url:
    url: https://corretto.aws/downloads/latest/amazon-corretto-11-x64-macos-jdk.pkg
    dest: /tmp
  when: java_vendor == "Amazon"

- name: Install Nginx
    apt:
      pkg: nginx
      state: installed
      update_cache: true
    when: ppastable|success
    notify:
     - Start Nginx

Expressions

Undefined Variables

Undefined Variables

Use is defined, is not defined. Do not attempt to dereference with "{{ ... }}" until it is established the variable is defined:

- name: Test whether a variable is not defined
  debug:
    msg: "some_var is not defined"
  when: some_var is not defined

- name: Test whether a variable is defined
  debug:
    msg: "some_var is defined"
  when: some_var is defined

Logical Operators

Parentheses can be used in expressions.

not

- name: "info"
  when: not java_updated
  debug:
    msg: "Java was NOT updated"

==

- name: "info"
  when: java.vendor == "Amazon" and java.version == 11
  debug:
    msg: "Java vendor is Amazon, Java version is 11"