DevOps Classroom Series – 28/Oct/2020

Evolution of Applications

• Monolith
• SOAP
• Microservices

Note:

• In this series we will be using insurance application as reference
• Refer Here for setting windows machine with software
• Refer Here for aws instance creation
• Refer Here for azure vm creation
• Refer Here to install and configure windows terminal.

Monolith

• Complete application is packaged as a unit and deployed on to the server
• The whole insurance application on server which will have one more server to store the data.
• There is an income tax submission season, where there will be lot of sales
  • Agents will create lot of quotes
  • Consumer logins might need to be created
• Insurance web portal is running on 3 servers which can handle approx 15000 parallel requests, in this tax season, users will be around 25k. So we need to have atleast 5 servers for web portal
• Docker containers can be used to run monolith applications

MicroServices

• Application is broken down into multiple individually executable services. With each service offering some functionality
• Microservices can be scaled individually
• Docker containers are best fit for microservices.
• Applications will be of two types
  • Stateless applications:
    • Donot store state locally, they store the state on external systems
    • Docker container is best fit for stateless applications
  • Stateful application
    • Stores all or some state locally
    • We can run them on docker, extra processing is required.

Docker Playground

• Is a virtual environment with virtual machines hosted with Docker pre-installed.
• We can use Docker Playground to experiment with docker.
• To use docker playground, we need docker login Refer Here to create a login

Docker Installation

• Linux Installation:
  • Create a centos 7 linux system on AWS: Navigate to Here

  curl -fsSL https://get.docker.com -o get-docker.sh
  sh get-docker.sh
  sudo service docker start
  sudo usermod -aG docker centos
  # logout & login
  docker --version
  docker info
  

  • Create an ubuntu instance (Azure):

  sudo apt update
  curl -fsSL https://get.docker.com -o get-docker.sh
  sh get-docker.sh
  

Lets explore images available

• Navigate to docker hub Refer Here

• Let navigate to nginx Refer Here

• Lets run the nginx container