YAML

• This is data representation format, which uses name/value pairs
• The basic format is <name>: <value>

topic: Docker

• types of data
  • Simple/Scalar
    • Text
    • number
    • boolean
  • Complex
    • list/array
    • map/dictionary/object
• Extension of YAML files is .yaml or .yml. YAML is a text file
• Simple yaml

url: directdevops.blog
author: khaja
isDailyUpdated: true
isLoginRequired: false
articlecount: 1000

• List example

---
Colors:
  - Black
  - White
Movies:
  - Avengers
  - Batman Begins

• Map/Dictionary/object

---
Address:
  flatno: 407
  building: Mythrivanam
  area: Ameerpet
  city: Hyderabad

• yaml about Quality Thought

---
name: QualityThought
url: https://qualitythought.in
courses:
  - name: Azure
    faculty: khaja
    duration: 90
  - name: AWS
    faculty: khaja
    duration: 90
  - name: DevOps
    faculty: khaja
    duration: 110
  - name: Manual Testing
    faculty: Ramana
    duration: 60
Branches:
  headoffice:
    flatno: 302
    building: nilgiri
    city: hyderabad
  devops:
    flatno: 407
    building: mythrivanam
    city: hyderabad

• Try writing about yourself in a yaml according to following structure

---
#qualification
yearofpassing: <number>
university: <text>
grade: text (A+|A|B|C)
----
# education
<name>: <qualification>

----
name: <text>
mobile: <text>
email: <text>
education: list(<education>)

• Example 1 (Postgraduate)

---
name: vishnu
mobile: '999999999'
email: vishnu@gmail.com
education:
  - mtech:
      yearofpassing: 2017
      university: jnu
      grade: A
  - btech:
      yearofpassing: 2015
      university: jntu
      grade: A+

• Example (graduate – BSc)

---
name: Swathi
mobile: '88888888'
email: swathi@outlook.com
education:
  - BSc:
      yearofpassing: 2020
      university: osmania
      grade: A+

• YAML will be used to define kuberentes manifests and docker compose files

Docker compose

• This was external tool, but now it is integrated as docker subcommand docker compose
• Compose allows use to specify the yaml file which helps in creating the below by specifying in a yaml file
  • networks
  • volumes
  • containers
• docker compose file will have the name of docker-compose.yml
• sample

---
version: '3.9'
services:
  web:
    image: nginx:latest
    networks:
      - hello-net
    volumes:
      - type: volume
        source: my-vol
        target: /tools
networks:
  hello-net:
    driver: bridge
volumes:
  my-vol:

• to start all the containers create a folder copy the docker-compose.yaml and execute docker compose up -d and to remove every thing docker compose down
  
• Refer Here for the compose file with instructions to run student course register which we have executed manually yesterday