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Kubernetes Application Deployment

Deployment, Service, ConfigMap, Secret, probes and resources.

~16 hours 7 phases
KuberneteskubectlYAML

Overview

Deploy an application to Kubernetes with a Deployment, Service, ConfigMap, Secret, probes and resource limits.

The problem

Deploy a resilient application to Kubernetes with proper resources and probes.

Why it matters

Deploying to Kubernetes is a foundational container skill.

What you'll build

  • Kubernetes manifests
  • A resilient deployment
  • Config and secrets

What you'll learn

  • Kubernetes
  • Probes
  • Resources

Business problem

Applications must run resiliently on Kubernetes.

Technical problem

Define workloads, services, config and resources correctly.

When you're done: A resilient Kubernetes application deployment.

Requirements

User requirements

  • Deploy an app
  • Auto-heal
  • Expose it
  • Configure safely

System requirements

  • Kubernetes cluster
  • kubectl

Functional requirements

  • Deployment
  • Service
  • ConfigMap
  • Secret
  • Probes
  • Resources

Non-functional requirements

  • Self-healing
  • Resource-bounded

Technical requirements

  • manifests
  • kubectl apply

Security requirements

  • Secrets separate
  • Least-privilege

Operational requirements

  • Documented apply

Constraints

  • Kubernetes

Success criteria

  • Pods healthy
  • Traffic flows
  • Resources set

Architecture

Ingress routes to Services backed by Deployment-managed Pods wired to Config and scaling.

Loading interactive diagram…

Flows

Request Flow

  1. 1

    Browser

    User requests the application over HTTPS.

  2. 2

    CDN / DNS

    Edge routes the request to the origin.

  3. 3

    Load Balancer

    Distributes traffic across healthy app instances.

  4. 4

    Application

    Handles the request, applies business logic.

  5. 5

    Cache

    Serves fast reads for hot data.

  6. 6

    Database

    Persists data and returns results.

Project Structure

Root of the client application source.

Setup

  1. 1

    Prerequisites

    You need the tools required by Kubernetes, kubectl, YAML installed and available on your PATH.

  2. 2

    Clone project

    Clone the repository locally.

    1. Clone the repository
    git clone <your-repo-url> <project-folder>
  3. 3

    Install dependencies

    Install the project dependencies.

    1. Initialize a Node.js project
    npm init -y

    Expected

    Creates a package.json with defaults.

    If it fails

    command not found: npm

    Fix

    Install Node.js LTS from the official site, then reopen your terminal.

  4. 4

    Configure environment

    Set the environment variables documented for this project. Never commit secrets.

    1. Create the environment file
    cp .env.example .env   # then edit values
  5. 5

    Start project

    Run the development command and confirm it starts.

    1. Start the development server
    npm run dev

    Expected

    Dev server starts; watch terminal for the local URL.

    If it fails

    Port 3000 is already in use

    Fix

    Run on another port: npm run dev -- --port 3001, or stop the conflicting process.

  6. 6

    Verify

    Open the printed local URL and confirm the primary flow works.

Build Phases

0 of 7 phases complete

  1. Objective: Establish the next milestone of the container platform.

    What changes: The project advances to the next coherent state, keeping the previous milestones working.

    Files touched

    Relevant source and configuration files for this milestone.

    Run

    1. Initialize a Node.js project
    npm init -y

    Expected

    Creates a package.json with defaults.

    If it fails

    command not found: npm

    Fix

    Install Node.js LTS from the official site, then reopen your terminal.

    Tasks

    • Implement the specific behaviour required for this milestone.
    • Verify the previous milestone still works.

    Validate: The milestone behaves as expected and does not break existing functionality.

    Common mistakes

    • • Skipping validation and moving on before confirming the milestone works.

  2. Objective: Establish the next milestone of the container platform.

    What changes: The project advances to the next coherent state, keeping the previous milestones working.

    Files touched

    Relevant source and configuration files for this milestone.

    Run

    1. Install the kubernetes package
    npm install kubernetes

    Expected

    Adds kubernetes to node_modules and package.json.

    If it fails

    npm ERR! network / EACCES

    Fix

    Check your network or run with sudo on Linux/macOS; on Windows run the terminal as Administrator.

    Tasks

    • Implement the specific behaviour required for this milestone.
    • Verify the previous milestone still works.

    Validate: The milestone behaves as expected and does not break existing functionality.

    Common mistakes

    • • Skipping validation and moving on before confirming the milestone works.

  3. Objective: Establish the next milestone of the container platform.

    What changes: The project advances to the next coherent state, keeping the previous milestones working.

    Files touched

    Relevant source and configuration files for this milestone.

    Run

    1. Start the development server
    npm run dev

    Expected

    Dev server starts; watch terminal for the local URL.

    If it fails

    Port 3000 is already in use

    Fix

    Run on another port: npm run dev -- --port 3001, or stop the conflicting process.

    Tasks

    • Implement the specific behaviour required for this milestone.
    • Verify the previous milestone still works.

    Validate: The milestone behaves as expected and does not break existing functionality.

    Common mistakes

    • • Skipping validation and moving on before confirming the milestone works.

  4. Objective: Establish the next milestone of the container platform.

    What changes: The project advances to the next coherent state, keeping the previous milestones working.

    Files touched

    Relevant source and configuration files for this milestone.

    Run

    1. Build the application for production
    npm run build

    Expected

    A production bundle is emitted to the output directory.

    If it fails

    Build fails with a type or syntax error

    Fix

    Read the error message, fix the referenced file, and re-run the build.

    Tasks

    • Implement the specific behaviour required for this milestone.
    • Verify the previous milestone still works.

    Validate: The milestone behaves as expected and does not break existing functionality.

    Common mistakes

    • • Skipping validation and moving on before confirming the milestone works.

  5. Objective: Establish the next milestone of the container platform.

    What changes: The project advances to the next coherent state, keeping the previous milestones working.

    Files touched

    Relevant source and configuration files for this milestone.

    Tasks

    • Implement the specific behaviour required for this milestone.
    • Verify the previous milestone still works.

    Validate: The milestone behaves as expected and does not break existing functionality.

    Common mistakes

    • • Skipping validation and moving on before confirming the milestone works.

  6. Objective: Establish the next milestone of the container platform.

    What changes: The project advances to the next coherent state, keeping the previous milestones working.

    Files touched

    Relevant source and configuration files for this milestone.

    Tasks

    • Implement the specific behaviour required for this milestone.
    • Verify the previous milestone still works.

    Validate: The milestone behaves as expected and does not break existing functionality.

    Common mistakes

    • • Skipping validation and moving on before confirming the milestone works.

  7. Objective: Establish the next milestone of the container platform.

    What changes: The project advances to the next coherent state, keeping the previous milestones working.

    Files touched

    Relevant source and configuration files for this milestone.

    Tasks

    • Implement the specific behaviour required for this milestone.
    • Verify the previous milestone still works.

    Validate: The milestone behaves as expected and does not break existing functionality.

    Common mistakes

    • • Skipping validation and moving on before confirming the milestone works.

Commands

1. Initialize a Node.js project
npm init -y

Expected

Creates a package.json with defaults.

If it fails

command not found: npm

Fix

Install Node.js LTS from the official site, then reopen your terminal.

2. Install the kubernetes package
npm install kubernetes

Expected

Adds kubernetes to node_modules and package.json.

If it fails

npm ERR! network / EACCES

Fix

Check your network or run with sudo on Linux/macOS; on Windows run the terminal as Administrator.

3. Start the development server
npm run dev

Expected

Dev server starts; watch terminal for the local URL.

If it fails

Port 3000 is already in use

Fix

Run on another port: npm run dev -- --port 3001, or stop the conflicting process.

4. Build the application for production
npm run build

Expected

A production bundle is emitted to the output directory.

If it fails

Build fails with a type or syntax error

Fix

Read the error message, fix the referenced file, and re-run the build.

Testing

Unit tests

  • Core logic and pure functions behave correctly.

    npm init -y

    Success: All unit tests pass without errors.

Integration tests

  • Components integrate correctly with data sources and services.

    npm test

    Success: Integration tests pass for the primary flows.

API tests

  • Endpoints respond to valid and invalid input correctly.

    npm test

    Success: API tests cover happy and failure paths.

End-to-end tests

  • A user can complete the primary journey end to end.

    npm run test:e2e

    Success: The main user journey completes successfully.

Security tests

  • No obvious security regressions are introduced.

    npm audit

    Success: No high or critical vulnerabilities.

Debugging & Troubleshooting

ImagePullBackOff

Why: Kubernetes cannot pull the container image.

Check: Inspect the pod events and image name.

kubectl describe pod <pod> | grep -A3 Events

Fix: Fix the image tag, registry auth, or availability.

Prevent: Verify images exist and pull policy is correct.

CrashLoopBackOff

Why: The container keeps starting and crashing.

Check: Read the container logs and previous logs.

kubectl logs <pod> --tail=30 && kubectl logs <pod> --previous

Fix: Fix the application error, missing config, or failing dependency.

Prevent: Add readiness/liveness probes to surface failures early.

Pod stuck Pending

Why: No node can fit the pod — resources, taints, or scheduling.

Check: Inspect events for scheduling failures.

kubectl describe pod <pod> | grep -A3 Events

Fix: Add capacity, remove taints, or reduce resource requests.

Prevent: Request resources your nodes can actually satisfy.

OOMKilled

Why: The container exceeded its memory limit.

Check: Inspect the container state and memory limits.

kubectl describe pod <pod> | grep -i memory

Fix: Raise the limit or reduce the application memory footprint.

Prevent: Set realistic limits and profile memory usage.

Security

Security is treated as a core requirement: input is validated, secrets are protected, and dependencies are kept up to date.

  • Input validation

    Validate and sanitize all user input before use.

  • Secrets management

    Store secrets in environment variables, never in source.

  • Dependency hygiene

    Regularly audit dependencies for known vulnerabilities.

Observability

Logs

  • Structured request logs with correlation IDs
  • Application-level error logs

Metrics

  • Request latency
  • Error rate
  • Throughput

Traces

  • Request tracing across the API and data layer

Health checks

  • A /health endpoint reporting readiness

Alerts

  • High error rate alert
  • Latency threshold alert

Dashboards

  • A dashboard showing requests, latency and errors

SLIs

  • Availability — Fraction of successful requests over the window
  • Latency — P95 response time

SLOs

  • Availability — 99.9% over 30 days
  • Latency — P95 under 500ms

Deployment

  1. 1

    Prepare for deployment

    Build the production artifact.

    1. Build for production
    npm run build
  2. 2

    Deploy

    Deploy to the project target platform following its documented steps.

    1. Deploy
    npm run deploy   # or the platform-specific command
  3. 3

    Verify

    Confirm the deployed application responds and its health check passes.

    1. Check health
    curl -I https://<your-deployed-url>

Documentation

Project Overview

Deploy an application to Kubernetes with a Deployment, Service, ConfigMap, Secret, probes and resource limits. This is a intermediate kubernetes project in the container platform space, built to demonstrate real engineering, not just copied code.

What You Will Build

- Kubernetes manifests - A resilient deployment - Config and secrets

Problem Statement

Applications must run resiliently on Kubernetes. Define workloads, services, config and resources correctly.

Technology Stack

Kubernetes, kubectl, YAML

Installation

Clone the repository and install dependencies with the documented commands.

Local Development

Run the development command and open the printed local URL.

Testing

Run the test commands documented in the Testing section and confirm they pass.

Deployment

Follow the documented deployment steps for this project's target platform.

Interview Explanation

Use the Interview section to explain the architecture, technology choices and trade-offs.

Build Process

Phases guide the build in 7 checkpoints. Complete each and validate before moving on.

Interview Prep

30-second pitch

I built Kubernetes Application Deployment — deploy a resilient application to kubernetes with proper resources and probes. It uses Kubernetes, kubectl, YAML and solves applications must run resiliently on kubernetes.

2-minute walkthrough

Deploy an application to Kubernetes with a Deployment, Service, ConfigMap, Secret, probes and resource limits. The core requirements were Deployment, Service, ConfigMap. I structured the work around Author Kubernetes manifests, Configure probes, Set resources and validated the result with the documented tests.

Architecture

The architecture is described by the interactive diagram in the Architecture section, which maps the request and deployment flows.

Why these technologies

I chose Kubernetes, kubectl, YAML because they are the pragmatic, well-supported tools best suited to building a kubernetes of this kind.

Why this architecture

The structure exists to keep concerns separated, make each piece testable, and scale the project cleanly as requirements grow.

At scale

At scale I would introduce caching, move to a service boundary structure, add proper observability, and enforce stricter contracts between components.

What can fail

The data source becomes unavailable, A dependency introduces a breaking change, Performance degrades under load, Configuration drift between environments

Monitoring

Monitoring is covered in the Observability section, focusing on requests, latency, errors and health checks.

Security

Security was handled by validating input, protecting secrets, and following the practices listed in the Security section.

Deployment strategy

Deployment follows the steps in the Deployment section for the target platform, with a health check to confirm success.

What I'd do differently

With more time I would add deeper test coverage, stronger observability, and automated deployment.

Practice Q&A

Why did you build Kubernetes Application Deployment?

To demonstrate Author Kubernetes manifests and Configure probes on a real, portfolio-worthy project.

What was the hardest part?

Coordinating the pieces so each stays correct as the project grows, and validating end to end.

How do you handle failure and scale?

By designing explicit failure handling and scale considerations into the architecture.

Extensions

  • Add deeper test coverage
  • Add observability and alerting
  • Harden security
  • Automate deployment

Completion Checklist

Prerequisite Projects

Next Steps

Recommended next

Prometheus + Grafana Monitoring Stack

Adds metrics and dashboards to the deployed app.