DevOps Classroom notes 07/Jul/2025

Writing Manifests

YAML

• This a file format for representing data which uses name value or key value pairs as a basic structure.
• YAML files generally have an extension of .yml or .yaml
• Basic structure

name-1: <value-1>
name-2: <value-2>
..
..
name-n: <value-n>

• Types of data
  • Simple/Scalar
    • Text
    • number
    • boolean
  • Complex
    • object/map
    • array/list
• Text

city: Hyderabad
city: 'Hyderabad'
city: "Hyderabad"

• number

population: 11.3

• boolean

metro: true
metro: yes

• list or array

areas: ['Ameerpet', 'SRNagar']
areas:
- Ameerpet
- SR Nagar
areas:
  - Ameerpet
  - SR Nagar

• object|map:

address:
  flatno: 601-b
  builing: nilgiri
  area: Ameerpet
  city: Hyderabad

• YAML Tutorial
  • Refer Here
  • Refer Here
• Generally YAML for a specific tool comes with a structure or schema
• Lets create a structure for filling a product information in ecommerce website
• create a yaml file based on following

name string
manufacturer: string
skus: sku array
gst: number (default: 18)

## sku 
name: string
description: string
price: number       

• Lets create a sample yaml file

---
name: Sony PlayStation5 
manufacturer: Sony
skus:
  - name: Slim
    description: Slim
    price: 54990
  - name: Muscular
    description: Muscular
    price: 154990

Lets start writing pod manifests

• Kubernetes Pods have containers
• Any thing which you create in k8s is an object
• Refer Here for k8s api reference
• Refer Here for pod spec

Example 1: A pod with nginx container

• Refer Here for the changes done
  
• API Server fills the status
  
  

Example 2: A pod with nginx container and alpine container

• Refer Here for the changes done
  

Example 3: A pod with alpine container without cmd

apiVersion: v1
kind: Pod
metadata:
  name: third
spec:
  containers:
    - name: alp
      image: alpine