Debug School: Rajesh Kumar

Kubernetes Day 1 Notes Nov 2026

Rajesh Kumar — Thu, 05 Nov 2026 09:30:22 +0000


Master
- Api Server        -> POD -> Container --> Image --> Google Registry
- Etcd              -> POD -> Container --> Image --> Google Registry
- Controller mgr    -> POD -> Container --> Image --> Google Registry
- Schedular     -> POD -> Container --> Image --> Google Registry   
- Proxy        -> POD -> Container --> Image --> Google Registry

- Kubectl
- Kubelet
- Docker 
- ContainerD
- Kubeadm init

Worker

- Proxy        -> POD -> Container --> Image --> Google Registry

- Kubectl
- Kubelet
- Docker 
- ContainerD
- Kubeadm join


Workstations
- Kubectl           ~/.kube/config (Yaml)


        ~/.kube/config

        cluster add - Api Server 
        user - 
        cert - 
        context - cluster add  + Users


kubeadm join 172.31.10.122:6443 --token owxbzk.mr4to3szdkc4qra0 --discovery-token-ca-cert-hash sha256:51547d7414361b8642aec5e484b68e2076d7f62335649966066296581f2b993d


Demo - Certifications

Desktop - Minikube - https://minikube.sigs.k8s.io/docs/
AWS - EKS - https://aws.amazon.com/eks/
AZURE - https://azure.microsoft.com/en-in/solutions/kubernetes-on-azure/get-started/
Google - GKE
Docker Desktop
Rancher Desktop - 



 20  cd
   21  ls
   22  kubectl
   23* clea
   24  kubectl get nodes
   25  kubectl cluster-info
   26  history
   27  kubectl get nodes
   28  clear
   29  kubectl
   30  kubectl version
   31  kubectl get nodes
   32  kubectl get pods --all-namespaces
   33  kubectl api-resources
   34  kubectl api-versions
   35  kubectl cluster-info
   36  history

Assignment - Kubernetes Day

Rajesh Kumar — Thu, 05 Nov 2026 07:02:07 +0000

What is kubernetes?
How kubernetes works?
Components of kubernetes?

Day 1 - Docker Notes

Rajesh Kumar — Thu, 05 Nov 2026 05:50:07 +0000

What is Docker?

        Container mgt  tool


        Docker Container Engine

        tool
        - save cost
                Container run you apps - Less CPU + LESS Ram + NO OS
        - save time
                1 hour - 5 mins - 1 sec
        - imp quality
                - Code + test

        mgt
                create + start + stop + pause + unp + kill + remove

        Container
                - Linux Kernel  
                - Namespaces
                - Cgroups
                - Networking
                - How Kernel works

                Lightweight app RUN time env
                Comprare to VMs

        Golang

        Version
                Community - 
                Enterprise - 
                26.X

        Solomon Hykes


How Docker works?
======================================================
HUMAN ---------> Docker Cli ------------------------------> DockerD(Server) -----------> ContainerD. ---> kernel 
                ---------------------------------------------------------
                                docker engine


Docker Components
=======================================================
Step 1 - Install Docker aka docker engine       DONE

Step 2 - Download Docker Image?             DONE

Step 3 - From Docker Registry https://hub.docker.com/       DONE
docker pull httpd


Step 4 - Run image - you get container..    

            1 Image - 1 con
            1 image --- Many containers



How to install it?
https://www.devopsschool.com/blog/docker-installation-and-configurations/#Docker_install_in_Ubuntu

   5  docker
    6  clear
    7  docker info
    8  clear
    9  docker version
   10  clear
   11  docker ps
   12  docker images
   13  docker ps -a
   14  history


How to use it?

create + start + stop + pause + unp + kill + remove

https://www.devopsschool.com/blog/lifecycle-of-docker-containers/


 15  clear
   16  docker pull httpd
   17  docker images
   18  clear
   19  docker create httpd
   20  docker ps
   21  docker ps -a
   22  docker create httpd
   23  docker ps -a
   24  docker start 83f78cc2499b
   25  docker ps -a
   26  docker start 83f78cc2499b
   27  docker ps -a
   28  docker start 0e232f4e73c2
   29  docker ps -a
   30  docker stop 83f78cc2499b
   31  docker ps -a
   32  docker restart 0e232f4e73c2
   33  docker ps -a
   34  docker pause 0e232f4e73c2
   35  docker ps -a
   36  docker unpause 0e232f4e73c2
   37  docker ps -a
   38  docker kil 0e232f4e73c2
   39  docker kill 0e232f4e73c2
   40  docker ps -a
   41  docker rm 83f78cc2499b
   42  docker ps -a
   43  history

How to use that containers?
============================================
GO INSIDE

ACCESS FROM OUTSIDE


 43  history
   44  clear
   45  docker run httpd
   46  docker ps -a
   47  docker run -d httpd
   48  docker ps
   49  docker exec -it ef243855a713 /bin/bash
   50  docker inspect ef243855a713
   51  curl http://172.17.0.6
   52  docker run -d -p 80:80 httpd
   53  docker ps
   54  history

LAZY COMMAND
========================
Run
Pull + create + start + attach

Run -d
Pull + create + start + do not attach

Azure Capstone: Deploy a Production-Style 3-Tier App on AKS with Terraform

Rajesh Kumar — Fri, 16 Oct 2026 13:24:05 +0000

The 10 questions. Each has the commands to find the answee....

Container Registry login server and its 3 repositories.
VNet range and the two subnet ranges.
VM size, node count and Kubernetes version of the cluster.
Pod names of the database, backend and frontend, and the node each runs on.
The backend's image, and whether it comes from their own registry.
The database's PVC name, size, storage class and the Azure Disk behind it.
The frontend's private load balancer IP versus the Application Gateway public IP.
Key Vault name, its secrets, the banner value and the Entra ID identity.
DNS name servers and the app A record, and whether public DNS agrees.
End to end: sign the guest book, show the message in the database before and after deleting the database pod, the WAF status code (403), and a screenshot.

Terraform Azure — Hands-On Assignments 2 - Linux

Rajesh Kumar — Tue, 13 Oct 2026 14:47:00 +0000

Assignment 2: Deploy Linux VM and Install Nginx Using Terraform Provisioner

Objective: Create an Ubuntu Linux VM in Azure and automatically configure Nginx Web Server using Terraform.

Requirements:

Create an Azure Resource Group, VNet, Subnet, NSG, Public IP, and Ubuntu Linux VM.

Use a Terraform provisioner to install Nginx.

Enable and start Nginx using systemctl.

Allow HTTP traffic on port 80 through the NSG.

Test Nginx by accessing http:// in a browser.

Submission: Write complete, standalone Terraform code and paste it into the comment section, along with the successful test result.

Terraform Azure — Hands-On Assignments - 1 Windows

Rajesh Kumar — Tue, 13 Oct 2026 14:46:16 +0000

Assignment 1: Deploy Windows VM and Install IIS Using Terraform Provisioner

Objective: Create a Windows Server VM in Azure and automatically configure IIS Web Server using Terraform.

Requirements:

Create an Azure Resource Group, VNet, Subnet, NSG, Public IP, and Windows VM.

Use a Terraform provisioner to install IIS Web Server.

Configure the IIS service to start automatically and ensure it is running.

Allow HTTP traffic on port 80 through the NSG.

Test IIS by accessing http:// in a browser.

Submission: Write complete, standalone Terraform code and paste it into the comment section, along with the successful test result.

Terraform Azure — Hands-On Assignments - Day 1

Rajesh Kumar — Mon, 12 Oct 2026 15:28:44 +0000

Terraform Azure — Hands-On Assignments

Assignment 1: Create Multiple Azure Subnets Using `count`

Objective: Learn Terraform's count meta-argument.

Requirements:

Create one Azure Resource Group in eastus.
Create one Virtual Network with CIDR 10.20.0.0/16.
Use a list(string) input variable containing ["10.20.1.0/24", "10.20.2.0/24"].
Use the count meta-argument to create two subnets named subnet-1 and subnet-2.
Both subnets must belong to the same Virtual Network.

Submission: Write the complete, standalone Terraform code and paste it into the comment section.

Assignment 2: Create Multiple Azure NSG Rules Using `for_each`

Objective: Learn Terraform's for_each meta-argument with a map variable.

Requirements:

Create one Azure Resource Group in eastus.
Create one Azure Network Security Group.
Define a map input variable containing two inbound rules: SSH (22, priority 100) and RDP (3389, priority 110).
Use the for_each meta-argument to create both NSG rules dynamically.
Allow inbound connections only from your own public IP address using /32.

Submission: Write the complete, standalone Terraform code and paste it into the comment section.

Instructions for Both Assignments

Each assignment must have independent, working Terraform code.
Use AzureRM provider 5.9.x.
Do not use data sources or modules.
Execute terraform init, terraform validate, and terraform plan.
Submit your complete code, not just the count or for_each block.
Do not include real passwords or credentials in your submission.

Terraform Oct 2026 Lab Reference

Rajesh Kumar — Mon, 12 Oct 2026 09:37:06 +0000

Lab 1 - Install Terraform in Windows

https://www.devopsschool.com/blog/terraform-install-configurations/

Lab 2 - Download Providers

https://registry.terraform.io/browse/providers

Lab 2 - How to set auth of Azure in Terraform

https://www.devopsschool.com/tutorials/azure-terraform-azure-authentication-azure-cli/
https://www.devopsschool.com/tutorials/azure-how-to-get-all-4-terraform-authentication-values-using-portal/

Microservices using Go and Kafka & Redis

Rajesh Kumar — Wed, 19 Aug 2026 10:21:21 +0000

Please
Full Name
HPE Email
Gmail

Day 1 - Golang - Aug 2026

Rajesh Kumar — Mon, 17 Aug 2026 04:24:01 +0000

How to install Go in Ubuntu
URL - Guide

Lets Run Fundamental Code in Go
https://www.devopsschool.com/tutorials/go-tutorials-foundation-level/

** Advance Go Array - Slice - Map - Struct **
https://www.devopsschool.com/tutorials/go-tutorials-arrays-slices-maps-and-structs/

Go Tutorials: Arrays, Slices, Maps, and Structs
https://www.devopsschool.com/tutorials/go-tutorials-arrays-slices-maps-and-structs/

Go Tutorial: Go Functions and Methods
https://www.devopsschool.com/tutorials/go-tutorial-go-functions-and-methods/

Go Tutorial: Go Interfaces
https://www.devopsschool.com/tutorials/go-tutorial-go-interfaces/

Go concurrency
https://www.devopsschool.com/tutorials/go-tutorials-go-concurrency-beginner-tutorial/

*How to setup k8 cluster *
https://github.com/certifications-tutorials/kubernetes-cluster-setup

capstone
https://github.com/devopsschool-demo-labs-projects/go-programming/tree/main/capstone

Package Dependecy in Go
15 mins - https://www.devopsschool.com/tutorials/go-tutorials-15-minute-lab-dependency-management-with-go-modules/
1 Hour - https://www.devopsschool.com/tutorials/go-tutorials-dependency-management-with-go-modules/
2 Hour - https://www.devopsschool.com/tutorials/go-tutorials-hands-on-lab-dependency-management-with-go-modules/

*Concurrency *
https://www.devopsschool.com/tutorials/go-tutorials-concurrency-made-simple/

Project - Capstone

Phase - 0 - experience monoth app [ 1 DB + 2 Service ]
Phase - 1 - 2 microservices

Phase - 2- Some issues --- We need to follow best prac -
https://github.com/devopsschool-demo-labs-projects/go-monolith-microservices-lab-demo

*Kafka - 1 *
https://www.devopsschool.com/tutorials/kafka-master-tutorials-series-1-an-introduction-of-kafka/
https://www.devopsschool.com/tutorials/kafka-master-tutorials-series-2-how-kafka-works-its-architecture-workflow/

How to use Codex for Coding?

Rajesh Kumar — Thu, 19 Mar 2026 13:29:24 +0000

================================

📁 Project Context

================================

Directory Structure:
-- /desd/dsds/dsds/dsd

Artifacts:

Database Schema: hospital.sql
Model: xgay.php
Controller: ddsadad.php
View: dskjsahdkja.php

================================

🎯 Role Definition

================================

Act as a senior software engineer with 15+ years of experience in:

PHP (Core + Laravel)
MySQL (schema design, indexing, query optimization)
Data Structures & Algorithms
Application Security (OWASP best practices)
Performance optimization (backend + frontend)
JavaScript (UX, async flows)

Your responses should be:

Practical and production-ready
Performance-conscious
Secure by design
Clean and maintainable

================================

🧩 Task 1: Code Review

================================

Objective:
Review the current implementation of the search filter.

Instructions:

Analyze the existing search/filter logic across model, controller, and view
Identify:
- Code quality issues
- Performance bottlenecks
- Security risks (SQL injection, validation gaps, etc.)
- Scalability concerns
Suggest improvements with reasoning

Action:
READ the provided files and give structured feedback.

================================

🧩 Task 2: Feature Design (Read-Only)

================================

Objective:
Extend the search filter with additional fields:

City
State
Country

Instructions:

Do NOT implement code yet
Provide:
- Step-by-step approach
- Required changes in:
- Database (if needed)
- Model
- Controller
- View/UI
- Query optimization strategy (indexes, joins, etc.)
- Validation and security considerations
- UX recommendations

Action:
Proceed ONLY after reviewing Task 1 feedback.

================================

🧩 Task 3: Conditional Implementation

================================

Condition A (If approach is approved):

Implement the feature end-to-end
Ensure:
- Clean, modular code
- No performance degradation
- Proper indexing and optimized queries
- Secure input handling
- Excellent UX (fast, intuitive filtering)
You may refer to any file as needed

Condition B (If approach is NOT approved):

Refine the design
Provide alternative approaches
Continue iteration until a satisfactory solution is reached

================================

⚠️ Important Guidelines

================================

Always think before coding
Prefer optimized queries over brute-force filtering
Avoid N+1 query problems
Follow Laravel best practices (if applicable)
Keep separation of concerns (MVC clean)
Suggest improvements beyond the asked scope if valuable

Articles: Small Machines for Understanding the World

Rajesh Kumar — Mon, 09 Mar 2026 02:26:41 +0000

Articles are odd little machines. They take sprawling reality—events, ideas, arguments, feelings—and run it through a set of conventions that turn “everything” into “something you can hold.” Not literally hold, of course, but you know the feeling: an article gives your mind a handle.

What an article is (besides text in columns)

At its simplest, an article is a promise: I’m going to guide your attention. That’s why even the most casual piece still has an invisible architecture—an opening that sets the frame, a middle that earns the frame, and an ending that changes the reader’s posture just a bit.

An article doesn’t just contain information. It performs selection:

What matters enough to mention?
What gets context, and what gets a passing nod?
What gets a quote, a statistic, a scene, a definition?

If a book is a landscape, an article is a footpath. It may be narrow, but it’s deliberate.

Articles as choices dressed up as certainty

Most articles wear the costume of authority. They use headings, confident verbs, tidy sequences, and clean conclusions. But underneath, they’re made of decisions and trade-offs.

Every writer runs into the same constraint: attention is finite. So articles compress. They prioritize. They cut away nuance not because nuance is bad, but because infinite nuance is indistinguishable from silence. An article is, in a sense, a controlled betrayal of complexity—ethical when it’s honest about its limits, unethical when it pretends the cuts didn’t happen.

That’s where trust lives: not in never simplifying, but in simplifying without lying.

Why articles have beginnings that “hook”

We like to pretend we read for facts, but we often read for orientation. The opening hook isn’t just a trick; it’s a handshake. It says, “Here’s why you should care, and here’s what kind of journey this will be.”

Some openings hook with:

A scene (placing you somewhere)
A question (placing you in uncertainty)
A claim (placing you in tension)
A statistic (placing you in scale)

The best ones don’t merely grab attention—they assign meaning to attention.

The secret social life of articles

Articles are also social objects. They’re forwarded, cited, excerpted, argued with, and reinterpreted. They live in group chats and comment sections, become “that thing we all read,” and sometimes mutate into simplified slogans. The original piece might be careful and balanced, but what survives socially is often the most portable sentence.

This is why writers obsess over:

the headline (the invitation),
the lede (the tone-setter),
the kicker (the final note people remember).

An article is written once, but it’s received many times—by readers with different moods, contexts, and agendas.

Genres: the same instrument, different music

A reported news piece, a personal essay, and a research explainer all look like “articles,” but they behave differently.

News tends to optimize for verification, timeliness, and clarity.
Essays optimize for voice, insight, and lived texture.
Explainers optimize for understanding, structure, and examples.
Opinion optimizes for argument, framing, and persuasion.

Each genre answers a different question:

What happened?
What did it feel like?
How does this work?
What should we think?

And yet they all share the same underlying job: escorting a reader from point A to point B without losing them on the stairs.

What readers really want

Readers don’t always want more information. Often they want:

a clearer model of what’s going on,
a sense of stakes without panic,
a map of competing viewpoints,
a feeling of being less alone in their confusion.

That’s why the most valued articles aren’t necessarily the longest or most “comprehensive.” They’re the ones that reduce noise and add shape. They take the mess and, with measured confidence, summarize it into a form that can travel.

The ethics of the “single piece”

Because articles feel complete, they’re dangerous when they become the only lens. A single article can’t contain an entire subject, only a slice of it. The responsible reader treats any one piece as a coordinate, not a destination: useful, but not final.

The responsible writer does the same—signals uncertainty, links out, admits what wasn’t covered, and resists turning a complex reality into a neat moral just because neat morals are shareable.

Why we keep writing them anyway

Despite their limitations, articles are one of the best tools we have for public thinking. They’re small enough to be read in a sitting, structured enough to build understanding, and flexible enough to carry reporting, storytelling, teaching, and argument.

An article is a human-scale container for curiosity.

And maybe that’s the core of it: articles are how we practice paying attention together—one crafted path at a time.

Debug School: Rajesh Kumar

Kubernetes Day 1 Notes Nov 2026

Assignment - Kubernetes Day

Day 1 - Docker Notes

Azure Capstone: Deploy a Production-Style 3-Tier App on AKS with Terraform

Terraform Azure — Hands-On Assignments 2 - Linux

Terraform Azure — Hands-On Assignments - 1 Windows

Terraform Azure — Hands-On Assignments - Day 1

Terraform Azure — Hands-On Assignments

Assignment 1: Create Multiple Azure Subnets Using count

Assignment 2: Create Multiple Azure NSG Rules Using for_each

Terraform Oct 2026 Lab Reference

Lab 1 - Install Terraform in Windows

Lab 2 - Download Providers

Lab 2 - How to set auth of Azure in Terraform

Microservices using Go and Kafka & Redis

Day 1 - Golang - Aug 2026

Project - Capstone

How to use Codex for Coding?

================================

📁 Project Context

================================

================================

🎯 Role Definition

================================

================================

🧩 Task 1: Code Review

================================

================================

🧩 Task 2: Feature Design (Read-Only)

================================

================================

🧩 Task 3: Conditional Implementation

================================

================================

⚠️ Important Guidelines

================================

Articles: Small Machines for Understanding the World

What an article is (besides text in columns)

Articles as choices dressed up as certainty

Why articles have beginnings that “hook”

The secret social life of articles

Genres: the same instrument, different music

What readers really want

The ethics of the “single piece”

Why we keep writing them anyway

Assignment 1: Create Multiple Azure Subnets Using `count`

Assignment 2: Create Multiple Azure NSG Rules Using `for_each`