Ansible YAML Indentation Error: How to Fix It (Examples) — Video Tutorial

Fix Ansible YAML indentation errors fast. Learn the root causes, common patterns, and how to prevent indentation issues in playbooks with practical examples.

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Tutorial summary

What you'll learn

Demo
Error
Fix
Conclusion
Understanding YAML Indentation in Ansible
The Golden Rules
Common Indentation Errors
Error 1: Tasks not indented under `tasks:`
Error 2: Module parameters not indented under module name
Error 3: Mixing tabs and spaces

Today we’re going to talk about Ansible troubleshooting and specifically about indentation errors. Demo The best way of talking about Ansible troubleshooting is to jump in a live Playbook to show you practically the error and how to solve it! Error ```yaml --- - name: blockinfile module demo hosts: all become: true tasks: - name: Generate /etc/hosts file ansible.builtin.blockinfile: state: present dest: /etc/hosts content: | 192.168.0.200 Playbook demo.example.com ``` Fix ```yaml --- - name: blockinfile module demo hosts: all become: true tasks: - name: Generate /etc/hosts file ansible.builtin.blockinfile: state: present dest: /etc/hosts content: | 192.168.0.200 Playbook demo.example.com ``` [code with ❤️ in GitHub](https://github.com/lucab85/ansible-pilot/tree/master/troubleshooting) Conclusion Now you know better how to troubleshoot the most common Ansible error about indentation. Understanding YAML Indentation in Ansible YAML (YAML Ain't Markup Language) is whitespace-sensitive. Ansible playbooks are written in YAML, which means **indentation determines the structure** of your configuration. Unlike Python (which uses 4 spaces by default), YAML is flexible about the number of spaces, but you must be **consistent**. The Golden Rules 1. **Never use tabs** — YAML only accepts spaces 2. **Be consistent** — pick 2 spaces (Ansible standard) and stick with it 3. **List items (`-`) must be at the same indentation level** as their siblings 4. **Key-value pairs under a mapping** must be indented deeper than the parent Common Indentation Errors Error 1: Tasks not indented under `tasks:` ```yaml ❌ WRONG — task is at same level as tasks key - name: my playbook hosts: all tasks: - name: install package ansible.builtin.apt: name: curl ``` ```yaml ✅ CORRECT — task is indented under tasks - name: my playbook hosts: all tasks: - name: install package ansible.builtin.apt: name: curl ``` Error 2: Module parameters not indented under module name ```yaml ❌ WRONG — path is at same level as file module - name: create file ansible.builtin.file: path: /tmp/test state: touch ``` ```yaml ✅ CORRECT — path is indented under file module - name: create file ansible.builtin.file: path: /tmp/test state: touch ``` Error 3: Mixing tabs and spaces This is invisible but devastating. Your editor might insert tabs that look like spaces. Use `cat -A playbook.yml` to reveal tabs (shown as `^I`). ```bash Check for hidden tabs $ cat -A playbook.yml | grep "\^I" ``` Error 4: Inconsistent indentation depth ```yaml ❌ WRONG — mixed 2-space and 4-space indentation - name: my playbook hosts: all tasks: - name: first task ansible.builtin.debug: msg: "hello" - name: second task ansible.builtin.debug: msg: "world" # 4 extra spaces instead of 2! ``` How to Prevent Indent

About this tutorial

Author: Luca Berton
Difficulty: Beginner
Read time: 4 min
Category: installation

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