DevOps Classroom notes 04/Feb/2026

YAML

• Ansible works in two ways
  • adhoc commands: for each module construct a ansible command
  • playbook: A declartive approach written in a yaml file.
• YAML is a data description format built on following principles
  • Name-value or key-value pairs
  • indentation (inspired from python)
• YAML is a format used by both applications and humans
• Since we deal with data where values can be of different types.
• YAML data types
  • Simple types
    • text
    • number
    • boolean
  • Complex
    • list/array (plural)
    • map/object
• To write a yaml file we use .yml or .yaml as extension generally
• YAML each element syntax is <name | key>: <value>
• Text

name: quality thought Technologies
name: 'quality thought Technologies'
name: "quality thought Technologies"

• Number: use numbers without quotes

age: 13

• boolean

offline: True
offline: yes

• list or array

courses: ["DevOps", "Python"]
courses:
- DevOps
- Python
courses:
  - DevOps
  - Python

• object/map

address:
  flatno: 601
  building: Nilgiri
  area: ameerpet
  city: hyderabad
address: { flatno: 601, building: Nilgiri, area: ameerpet, city: hyderabad }

• Complete yaml file

---
name: quality thought Technologies
age: 13
offline: yes
courses:
  - DevOps
  - Python
address:
  flatno: 601
  building: Nilgiri
  area: ameerpet
  city: hyderabad

• Website to learn yaml
  • Learn YAML in y minutes
  • Ansible docs
• When we are writing a yaml for a specific tool, there will be a structure to follow
• Lets take yesterdays table and write them in yaml form
• Syntax

- name: <describe your step>
  <module-name>:
    <param-1>: <value-1>
    ..
    <param-n>: <value-n>

• The modules found in last session

Sno	Command	Module	Parameters
1	apt update	ansible.builtin.apt	update_cache: true
2	apt install nginx	ansible.builtin.apt	name: nginx, state: present
3	systemctl enable nginx.service	ansible.builtin.systemd	name: nginx.service, enabled: true
4	systemctl start nginx.service	ansible.builtin.systemd	name: nginx.service, state: started
5	apt install unzip	ansible.builtin.apt	name: unzip, state: present
6	wget https://templatemo.com/tm-zip-files-2020/templatemo_589_lugx_gaming.zip	ansible.builtin.get_url	url: , dest: /tmp/templatemo_589_lugx_gaming.zip
7	unzip templatemo_589_lugx_gaming.zip	ansible.builtin.unarchive	src: /tmp/templatemo_589_lugx_gaming.zip, remote_src: true, dest: /var/www/html/

Yaml equivelent

1. update cache

- name: update caches
  ansible.builtin.apt:
    update_cache: yes

1. installing nginx

- name: installing nginx
  ansible.builtin.apt:
    name: nginx
    state: present

1. enable nginx

- name: enable nginx
  ansible.builtin.systemd_service:
    enabled: yes
    name: nginx.service

1. start nginx

- name: ensure nginx is started
  ansible.builtin.systemd_service:
    name: nginx.service
    state: started

you fill the rest.

• To learn yaml use the following prompt.

Act as yaml tutor, Give me simple data and a question to write yaml, i will fill the yaml structure and you validate, correct and make me learn yaml