MERN App Deployed on Kubernetes | 3 TIER WEB APPLICATION via Kubeadm..

MERN App Deployed on Kubernetes | 3 TIER WEB APPLICATION via Kubeadm..

Many, many thanks to DevOps wale bhaiya Shubham Londhe, aka TrainWithShubham San ..............

Your teaching style is just next-level—so crystal clear that even a beginner or student can follow along with ease..

I followed every single step you taught, documented everything with screenshots , and despite hitting a few real-world DevOps errors (like ImagePullBackOff), I pushed through and fixed them like a true DevOps engineer—because that’s what we do.

Built & containerized a full MERN app

Set up a Kubernetes cluster using kubeadm

Installed CRI-O, Calico, Kubelet

Debugged and resolved image issues

Documented all steps + blog in pdf (check profile!)

Going for a "Ride with Shubham Bhaiya" on this one has been a super fun and rewarding journey.

Sirji, your desi-style deep knowledge delivery is just unbeatable. Thanks for being a rockstar teacher!

Project Summary: Deploying a MERN Stack App on Kubernetes using Kubeadm

Tech Stack Used:

MERN: MongoDB, Express.js, React.js, Node.js

Kubernetes: Cluster setup via kubeadm

Container Runtime: CRI-O

Networking: Calico CNI plugin

Infrastructure: 2 Ubuntu 24.04 VMs (T2.medium)

Docker: For image building & pushing to Docker Hub

Key Components:

3-Tier Architecture Breakdown:

Presentation: React (Frontend)

Application Logic: Express + Node.js (Backend)

Data Layer: MongoDB

Kubernetes Cluster Setup:

1 Master Node

1 Worker Node

Installed and configured CRI-O as container runtime

Installed kubelet, kubeadm, and kubectl

Networking Configurations:

Loaded required kernel modules (overlay, br_netfilter)

Set sysctl parameters for bridging and IP forwarding

Installed Calico plugin for pod networking

Image Creation & Deployment:

Built Docker images for frontend & backend

Tagged and pushed to Docker Hub

Resolved an ImagePullBackOff error by correcting image tag

Applied YAMLs for:

Persistent Volumes

Persistent Volume Claims

MongoDB & Redis deployments

Frontend and Backend deployments

Namespace & DNS Management:

Created wanderlust namespace for isolation

Patched CoreDNS replicas to ensure resolution across nodes

Final Outcome:

Successfully accessed the app:

Frontend: http://:31000

Backend: http://:31100

Application fully functional!

How even one missing tag (latest) can break a whole setup

TO FOLLOW for more projects & updates----

my GitHub profile - https://lnkd.in/gFnaRiS6

nextwork org link- https://lnkd.in/gpXTAeY5

dev.to -https://lnkd.in/gFRpihNq

medium.com- https://lnkd.in/g_iCpfsb

hashnode- https://lnkd.in/gSqR6GAn

bento- https://lnkd.in/g9zgrdhw

For a detailed breakdown with notes, explanations, and complete practical steps the documented version has been attached below. https://www.linkedin.com/posts/devops-methodology_deploying-a-mern-stack-application-on-k8s-activity-7332030488578064384--zid?utm_source=share&utm_medium=member_desktop&rcm=ACoAAE0aWosBwvnsFU3QDf3zF_WnWYAe3ZS1mlk

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