Use default omit to skip an optional module argument

Short answer

Use default(omit) so Ansible omits a module argument when the variable is undefined instead of sending a value.

Request

touch files with optional mode using default(omit)

Example

A quick heads-up: Every environment is different. Review and test this example before you run it on systems you care about.

---
- name: Touch files with an optional mode
  hosts: all
  gather_facts: false
  tasks:
    - name: Touch files with an optional mode
      ansible.builtin.file:
        dest: "{{ item.path }}"
        state: touch
        mode: "{{ item.mode | default(omit) }}"
      loop:
        - path: /tmp/foo
        - path: /tmp/bar
        - path: /tmp/baz
          mode: "0444"

How it works

default(omit) removes the module argument when the value is undefined. Ansible does not send mode for /tmp/foo or /tmp/bar, so the system umask applies. Only /tmp/baz receives mode 0444.

When to use it

• Optional module arguments that should fall back to system defaults
• Loop items that set a field only on some entries

Requirements

• Ansible: >=2.14

Validation

• Syntax validated
• Not execution-tested
• Last verified 2026-09-16