Kubernetes: The New Norm for Container Orchestration

Deploying and managing containerized applications can be difficult to do at scale. Moving to containerize applications with just a couple of things in a Docker container can be no big deal; but as the application grows, the tradeoffs also become complex such as scaling out, staying resilient in the face of failures, routing traffic in a meaningful way, and of course, maintaining zero downtime.


introduction

Kubernetes. Commonly abbreviated as K8s, is an open-source system to automate the running, scaling, and management of containerized applications. Kubernetes was created initially by Google and is currently owned by the Cloud Native Computing Foundation (CNCF).


Kubernetes gives a system where applications operate through containers on a batch of machines. It should be appreciated that software packages like Docker can bundle an application into containers, but Kubernetes enables lazy automated deployment of the containers onto several machines concurrently. Kubernetes struggles/compares to maintain an application valid with availability, traffic request demand, and failover from failure/strikes.


Why though Kubernetes? 

So you have your application up and running with Docker - awesome! But how do you... 

- Automatically scale your application to handle huge traffic loads? 

- Restart it if a container crashes? 

- Deploy updates that users don't even notice? 

- Route traffic intelligently to different versions (A/B testing)? 

- Consistently run the same setup across development, staging, and production? 


This is exactly what Kubernetes was designed to automate for you!

With Kubernetes you have:

Self-healing - You have a container that goes failed the server restarts it.

Auto-scaling - Your application can go up and down, based on traffic/load.

Zero-downtime deployments - You can manage changes some minimum risk to the end-user with rolling updates.

Load balancing - Distributes incoming requests across the pods.

Infrastructure abstraction - You don't need to bother if you are running on AWS or GCP, or your laptop.

In short: Kubernetes lets you sleep at night when your application suddenly goes viral.



Kubernetes Architecture Overview

Kubernetes is based on Control Plane + Node architecture. 

Control Plane - The Brains of Kubernetes, This is the part of Kubernetes that makes the decisions. 

API Server - The entry point. You (or other tools) interact with Kubernetes through this. 

Scheduler - Binds pods (your app instances) to nodes (machines). 

Controller Manager - Watches everything, trying to maintain the desired state. 

etcd - Key-value store acting like the brain's memory. Where it keeps all cluster data. 


Nodes - The Workers of Kubernetes These are the servers (virtual or physical), that run your containers. 

Kubelet - Talks to the Control Plane and ensures your containers are up and running as intended. 

Container Runtime - e.g. Docker, containerd. This is what runs the containers! 

Kube-proxy - it is used to manages network rules and load-balancing between pods. 


Analogy: 

Think about an airport. 

Control Plane = Air Traffic Control 

Nodes = Airplanes 

Pods = Passengers 

Scheduler = Dispatcher assigning passengers to airplanes 



Core Features of Kubernetes

Here are a few reasons Kubernetes is considered revolutionary:

Self-healing: Pods fail? Kubernetes will reinstate them automatically.

Service discovery & load balancing: Forget about hardcoding IPs.

Automated rollouts/rollbacks: During update, deploy new image safely or roll back as needed.

Horizontal scaling: Pods added automatically during peak load.

Secrets & config management: Store credentials or configs securely.

Many of these features accelerate development and operations, all while not breaking things.



Kubernetes Core Concepts

The core concepts of Kubernetes are subset objects:

Pod: The smallest object in Kubernetes, a pod can have one or more closely related containers.

Example: A Node.js app with a Redis sidecar in the same pod.

Deployment: Specifies how your app gets deployed, updated, and scaled.

Example: You want three replicas of your backend API? Use a Deployment.

ReplicaSet: Offers a way to guarantee that a certain number of pods are running at all times. If one of your three pods goes down, ReplicaSet will take care of bringing it back up automatically.

Service: Abstracts a stable network endpoint for pods.

Types:

  • ClusterIP (internal communication)
  • NodePort (expose on a port of the node)
  • LoadBalancer (managed external traffic through the cloud)

ConfigMap & Secret

They allow you to store configuration and sensitive data independently from your app.

Example: You could store DB connection strings or API keys securely.



When To Use Kubernetes?

Kubernetes is not for everything. Kubernetes is a great choice if:

  • You have a microservice based architecture.
  • You are expecting bursts in traffic patterns (examples: holiday periods of sales, launches).
  • You want to have high availability and automatically handle failover.
  • You plan on deploying to multiple cloud providers or regions.

If you are building a personal blog or building a single monolith app? Kubernetes might be more than you need.



Kubernetes Real-World Use Cases

Now, let's see a few of the big companies (and small teams) that are using it: 

Netflix – The ability to automatically scale operations: Netflix uses Kubernetes to perform video transcoding by automatically scaling based on demand.

Airbnb – Safe / Fast deployments: Airbnb was able to reduce the time it takes to deploy while at the same time keeping rollbacks safer with Kubernetes.

E-commerce giants (and other companies) (ex. Flipkart, Amazon):  The scale of their services required during super sales (ex. Black Friday sales, Diwali) was too unpredictable which is why Kubernetes autoscaled their services to allow millions of requests per minute to happen.

Startups: Startups (and my company!) also utilize GKE, EKS, DigitalOcean Kubernetes, etc. for simple DevOps in ops, cost effective, and being lean and nimble. 

Personal Note: 

Kubernetes has been the most enjoyable experience when I crafted a full stack application for a client deployment using Kubernetes on DigitalOcean. The best part is the update was completed with zero downtime (and the client thought I was magic!).



Final Thoughts

Kubernetes is great for resource-orientated architecture for containerized apps—especially when things start to change and scale. Scaling, upgrades, and availability are managed without you manually restarting containers or considering the network spike in an instant. On the contrary, it is not the easiest thing to learn, and for small projects it is like using a jet engine to make a bicycle go fast. However, if you building something large or intending to scale quickly, allocating into Kubernetes will save time and pain. If you are part of a small team and you want to take advantage of its benefits without the load of managing everything, you can go with a managed Kubernetes service.