How does a basic web application work? Why do we need Kubernetes?

Before we understand how Kubernetes work, we must understand how a basic web application work. Based on the Kubernetes document “Kubernetes is a portable, extensible, open source platform for managing containerized workloads and services, that facilitates both declarative configuration and automation”. This is for beginners to understand how Kubernetes works so I am trying to focus on the “managing containerized workloads” part.

For illustration, imagine we have a web application with a good amount of traffic. Also, we have containerized the application. To make sure the AVAILABLITY of the application, is hosted in 4 servers and we have a load balancer to route traffic into all the servers. The application is also connected to a backend database to get information.

Now we need monitoring in place to make sure all the servers or VM are up and running. We have different tools to monitor application/server health but in case of any issue in any of the servers, we might need manual intervention and make sure the application is up and running on that server.

What if we have a tool that can monitor server /application health, and start/restart the application in case of any issues. This is what exactly Kubernetes does. There are much more features Kubernetes has but this is the important one.