YAML (short for "YAML Ain't Markup Language") is a human-readable data serialization language used for storing and exchanging data such as XML or JSON but compared to XML or JSON, YAML is easy to read and write and which makes it more concise than XML and easier to parse than JSON. It is used in various applications and programming languages for file configuration in applications like Kubernetes, docker and ansible and it is used in Python and Ruby programming languages.

Why YAML is required for DevOps?

YAML is used in DevOps to define and manage application configuration and Infrastructure as code (IaC) and tools like Ansible, Docker and Kubernetes.

Things to Understand

• Key Value

• Objects

• Lists

• List of Objects

• Multiline

Open any editor or just use https://replit.com/

Create a file as first.yml or first.yaml

#Key Value
name : Amit
age : 22
#objects
Subject:
    name : "Learning Devops"
    language : YAML

Now save this file.

Create a new python in the same directory named test_yml.py to validate the yml file.

#Importing the yaml library
import yaml

with open ('first.yml','r') as file:
    try:
        print(yaml.safe_load(file))
    except yaml.YAMLError as exc:
        print(exc)

Now Save the file and go to the terminal if you are in the local editor

python3 test_yml.py

Output:

Now will see how to create the list.

#Key Value
name : Amit
age : 22
#objects
Subject:
    name : "Learning Devops"
    language : YAML
#Creating List
social_connection :
    - Twitter-Amitwtz
    - Linkdein-amitdevops
#Multiline Comment
test : |
    This is multi line string
    for the YAMl Testing
#List of Objects
AWS_Services :
    - EC2 :
        name : Web_App
        Storage : 10GB
        AMI : Ubuntu
    - ELB :
        First : Application Load Balancer
        Second : Network Load Balancer
        Third : Classic Load Balncer

Now again check and validate

Output

I am attaching the replit template for you to check

• Click on Show Files

• Check the first.yml file

• Open main.py file and run the file

Want to know more about YAML ?

Checkout this youtube video by @TrainWithShubham

Conclusion : YAML is used for searilization of data and extremly important for docker compose.