Understanding Kubernetes: Why It's Essential for Modern Applications
Tags: kubernetes, containerisation, docker, devops
Published: 2024-06-20 15:59:08

### Introduction:
Welcome back to our CK2024 blog series! Today we dive into the fundamentals of Kubernetes. This is the fourth instalment in our series where we've already covered the basics of containers, how to containerize an application, why we need containers, and the concept of multi-stage builds. If you haven’t caught up with the previous posts, I highly recommend doing so to get the most out of this one.

## The Fundamentals of Kubernetes
In our last few posts, we explored containerization and its benefits. Now, let’s look at Kubernetes – a powerful orchestration tool that enhances the management and scalability of containerized applications.


![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/2l2m8gdba3cin9b4v4d0.jpeg)

#### Why Do We Need Kubernetes?
Imagine you have a small application with a few containers running on a virtual machine. Everything works perfectly until one container crashes, impacting your users. You might assign a team to fix the issue, but what if it happens during off-hours or multiple containers crash simultaneously? The situation becomes even more challenging if your application scales up to hundreds or thousands of containers. Managing such a scenario manually is not feasible. Here’s where Kubernetes comes in.

#### Challenges with Docker Containers Alone
Running applications solely on Docker containers presents several challenges:

- **Manual Recovery**: If a container crashes, someone needs to manually restart it.
- **Scaling Issues**: Manually scaling containers to meet demand can be difficult and inefficient.
- **Resource Management**: Managing resources across multiple containers is complex.
- **Networking**: Establishing secure and reliable networking between containers is challenging.
- **High Availability**: Ensuring your application is always available requires significant effort.
- **Load Balancing**: Distributing traffic effectively across containers is not straightforward.
- **Service Discovery**: Keeping track of running containers and their endpoints is a hassle.

### How Kubernetes Solves These Problems

Kubernetes automates many of these tasks, providing a robust solution for container orchestration:

1. **Self-Healing**: Kubernetes automatically restarts failed containers and reschedules them on healthy nodes.
2. **Automated Scaling**: It can scale applications up or down based on demand using the Horizontal Pod Autoscaler.
3. **Efficient Resource Management**: Kubernetes optimizes the use of resources, ensuring high performance and cost-effectiveness.
4. **Networking Solutions**: It offers a unified networking layer, simplifying communication between containers.
5. **High Availability**: Kubernetes ensures your application remains available through node redundancy and load balancing.
6. **Service Discovery**: Built-in service discovery mechanisms make it easy for containers to find and communicate with each other.

### When Not to Use Kubernetes
While Kubernetes is a powerful tool, it's not always the best choice. For small applications with only a couple of containers, Kubernetes can be overkill. Managing Kubernetes clusters requires additional administrative effort and resources. For simpler needs, tools like Docker Compose or even running containers directly on a virtual machine might be more suitable and cost-effective.

#### Conclusion
I hope this post has given you a solid understanding of why Kubernetes is essential for modern applications and the challenges it addresses. Stay tuned for our next post where we will delve into the architecture and basic fundamentals of Kubernetes.

See you soon in the next installment!