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0x09. Web infrastructure design

Concepts

For this project, we expect you to look at these concepts:

Web Infrastructure
Resources
Learning Objectives

At the end of this project, you are expected to be able to explain to anyone, without the help of Google:

General

  • You must be able to draw a diagram covering the web stack you built with the sysadmin/devops track projects

  • You must be able to explain what each component is doing

  • You must be able to explain system redundancy

  • Know all the mentioned acronyms: LAMP, SPOF, QPS

Requirements

  • A README.md file, at the root of the folder of the project, is mandatory

  • For each task, once you are done whiteboarding (on a whiteboard, piece of paper or software or your choice), take a picture/screenshot of your diagram

  • Upload a screenshot, showing that you completed the required levels, to any image hosting service (I personally use imgur but feel free to use anything you want).

  • You will also have to whiteboard each task in front of a mentor, staff or student - no computer or notes will be allowed during the whiteboarding session

  • Focus on what you are being asked:

  • Cover what the requirements mention, we will explore details in a later project

  • Keep in mind that you will have 30 minutes to perform the exercise, you will get points for what is asked in requirements

  • Similarly in a job interview, you sholistd answer what the interviewer asked for, be careflist about being too verbose - always ask the interviewer if going into details is necessary - speaking too much can play against you

  • In this project, again, avoid going in details if not asked

Tasks

0. Simple web stack

0. Simple web stack

A lot of websites are powered by simple web infrastructure, a lot of time it is composed of a single server with a LAMP stack.

On a whiteboard, design a one server web infrastructure that hosts the website that is reachable via www.foobar.com. Start your explanation by having a user wanting to access your website.

  • You must use:

    • 1 server

    • 1 web server (Nginx)

    • 1 application server

    • 1 application files (your code base)

    • 1 database (MySQL)

    • 1 domain name foobar.com configured with a www record that points to your server IP 8.8.8.8

  • You must be able to explain some specifics about this infrastructure:

    • What is a server

    • What is the role of the domain name

    • What type of DNS record www is in www.foobar.com

    • What is the role of the web server

    • What is the role of the application server

    • What is the role of the database

    • What is the server using to communicate with the computer of the user requesting the website

  • You must be able to explain what the issues are with this infrastructure:

    • SPOF (Single Point of Failure)

    • Downtime when maintenance needed (like deploying new code web server needs to be restarted)

    • Cannot scale if too much incoming traffic

Please, remember that everything must be written in English to further your technical ability in a variety of settings.

GitHub repository:
alx-system_engineering-devops
Directory:
0x09-web_infrastructure_design
File:
0-simple_web_stack

    1. Distributed web infrastructure

    1. Distributed web infrastructure

    On a whiteboard, design a three server web infrastructure that hosts the website www.foobar.com.

    Requirements:

    • You must add:

      • 2 servers

      • 1 web server (Nginx)

      • 1 application server

      • 1 load-balancer (HAproxy)

      • 1 set of application files (your code base)

      • 1 database (MySQL)

    • You must be able to explain some specifics about this infrastructure:

      • For every additional element, why you are adding it

      • What distribution algorithm your load balancer is configured with and how it works

      • Is your load-balancer enabling an Active-Active or Active-Passive setup, explain the difference between both

      • How a database Primary-Replica (Master-Slave) cluster works

      • What is the difference between the Primary node and the Replica node in regard to the application

    • You must be able to explain what the issues are with this infrastructure:

      • Where are SPOF (Single Point of Failure)

      • Security issues (no firewall, no HTTPS)

      • No monitoring

    Please, remember that everything must be written in English to further your technical ability in a variety of settings.

    GitHub repository:
    alx-system_engineering-devops
    Directory:
    0x09-web_infrastructure_design
    File:
    1-distributed_web_infrastructure

      2. Secured and monitored web infrastructure

      2. Secured and monitored web infrastructure

      On a whiteboard, design a three server web infrastructure that hosts the website www .foobar.com it must be secured, serve encrypted traffic, and be monitored.

      Requirements:

      • You must add:

        • 3 firewalls

        • 1 SSL certificate to serve www.foobar.com over HTTPS

        • 3 monitoring clients (data collector for Sumologic or other monitoring services)

      • You must be able to explain some specifics about this infrastructure:

        • For every additional element, why you are adding it

        • What are firewalls for

        • Why is the traffic served over HTTPS

        • What monitoring is used for

        • How the monitoring tool is collecting data

        • Explain what to do if you want to monitor your web server QPS (Queries Per Second)

      • You must be able to explain what the issues are with this infrastructure:

        • Why terminating SSL at the load balancer level is an issue

        • Why having only one MySQL server capable of accepting writes is an issue

        • Why having servers with all the same components (database, web server, and application server) might be a problem

      Please, remember that everything must be written in English to further your technical ability in a variety of settings.

      GitHub repository:
      alx-system_engineering-devops
      Directory:
      0x09-web_infrastructure_design
      File:
      2-secured_and_monitored_web_infrastructure

        3. Scale up

        3. Scale up

        Requirements:

        • You must add:

          • 1 server

          • 1 load-balancer (HAproxy) configured as a cluster with the other one

          • Split components (web server, application server, database) with their own server

        • You must be able to explain some specifics about this infrastructure:

          • For every additional element, why you are adding it

        Please, remember that everything must be written in English to further your technical ability in a variety of settings.

        GitHub repository:
        alx-system_engineering-devops
        Directory:
        0x09-web_infrastructure_design
        File:
        3-scale_up
          Last modified: 05 September 2024
          System engineering & DevOps - Web stack0x0C. Web server