Ansible Conditionals: Difference between revisions
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| Line 30: | Line 30: | ||
==Undefined Variables== | ==Undefined Variables== | ||
{{Internal|Ansible_Concepts#Undefined_Variables|Undefined Variables}} | {{Internal|Ansible_Concepts#Undefined_Variables|Undefined Variables}} | ||
Do not attempt to dereference with "{{ ... }}" until it is established the variable is defined: | Use <code>is defined</code>, <code>is not defined</code>. Do not attempt to dereference with "{{ ... }}" until it is established the variable is defined: | ||
<syntaxhighlight lang='yaml'> | <syntaxhighlight lang='yaml'> | ||
- name: Test whether a variable is defined | - name: Test whether a variable is defined | ||
Revision as of 20:34, 5 July 2021
External
Internal
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
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 defined
debug:
msg: "some_var is not defined"
when: some_var is not defined
Logical Operators
Parentheses can be used in expressions.
and
or
not
- name: "info"
when: not java_updated
debug:
msg: "Java was NOT updated"