K8s Series: Introduction to Kubernetes

Kubernetes is an open-source container orchestration system. Originally developed by Google in 2014, Kubernetes was initially used as their in-house solution to provide a container orchestration layer. However, Google later made it available as an open-source application used throughout the world. 

Kubernetes is a common point of discussion among software engineers in organizations that run the gamut, whether they are big tech giants seeking to manage enormous workloads or small startups trying to keep costs low and solutions flexible. But, of course, not all applications are meant for the cloud; Kubernetes is increasingly used to deploy scalable applications across a wide range of infrastructure, including public cloud, multi-cloud, and hosted infrastructure.

But what exactly is Kubernetes, and why is it so important in modern software development? To grasp why Kubernetes is fundamental to software development, it's important to understand what containers are and why orchestration matters.

Container Orchestration: The Kubernetes Origin Story

As the successors to virtual machines (VMs), containers allow engineers to package applications into independent, isolated services. Those services can then be scaled up and down as required. VMs are incredible resource hogs that need full-fledged operating systems to function, while containers make do with a single OS kernel. 

Containers are lightweight and efficient — essential qualities for deploying an application at scale. Containerization makes it possible to scale up individual functions of a cloud application without affecting the rest of the application components. Each service operates independently, without drawing on the resources allocated to another.

These containers are usually packaged as ‘images’ that include all of the dependencies for the service. Instantiating an image and allocating it to required resources is what initializes a container. 

Once introduced, containerization gained popularity, but the technology faced a challenge. Most applications require hundreds or even thousands of containers and manually overseeing it all became impossible at scale. This is where orchestration comes in.

The Arrival of Kubernetes

The sole purpose of Kubernetes is to ‘orchestrate’ the creation and deployment of containers and streamline the whole process with automation.

Similar to the conductor in a musical orchestra, Kubernetes directs the flow containers - when they have to be spun into existence and when they have to be wound down. Kubernetes is responsible for ensuring that all the various containerized services are working in perfect tandem with each other, allocating resources as required. In short, Kubernetes is the framework that takes the discordant notes of individual containers and brings them together in a cohesive application.

The Anatomy of a Kubernetes Cluster

At the core of Kubernetes deployment are worker machines called Nodes. These workers run multiple Pods according to their load and service requests. Each pod consists of a set of containers that constitute a single service.

Overseeing all these nodes and managing the pod creation is the Control Plane. The control plane includes the top-level code of a Kubernetes cluster, including the API server that interfaces with the outside world, processing requests and providing information.

Advantages of Kubernetes

Aside from the obvious benefit of creating and managing an otherwise impossibly large number of containers and simplifying software development, there are some other vitally important advantages of Kubernetes.

Rapid Scaling

The most well-known feature of a Kubernetes cluster is its ability to scale rapidly. There is no need for physically adding more servers or even initializing new VMs — containers can be created almost instantly, sharing the increased workload without slowing down performance.

And as the containers separate the individual processes of the application, you can scale up just the services that need the extra resources without having to replicate the whole application needlessly. Once you don’t need the extra capacity, you can just as easily scale down the application, so you don’t waste resources, which is particularly helpful when working in the cloud, where you pay for those resources whether you need them or not.

Security

Another important reason for adopting the K8s framework is security. Traditional cloud applications are vulnerable to cross-service tampering, where a compromised image can gain access to other services and change its parameters.

With Kubernetes, it is a trivial task to apply a basic rule set that filters containers across the system, rejecting requests that do not adhere. Furthermore, the orchestration platform allows for runtime monitoring of nodes to root out malicious containers and limit their exposure.

Continuous Development

Updating the typical application can be tricky. You cannot pick and choose which feature to modify; to change anything, you need to shut down the whole thing. This process is complicated in servers offering essential cloud services.

But with Kubernetes, continuous development is a piece of cake. Since each aspect of the application is its own container, modifying a single service does not affect the rest of the framework. Better yet, you don’t even have to take anything offline. Instead, updated containers can be spun into existence, gradually replacing the previous images without causing any lapse in service.

Cross-Platform

Kubernetes will not lock you into a particular programming language or tech ecosystem. For example, the Kubernetes framework itself was coded in Google’s programming language, Go, but Kubernetes allows you to develop your application with any language or tool.

Kubernetes uses a language-agnostic API that can communicate through standard HTTP callbacks. You can also use any of the client libraries for all major languages for more ease, abstracting away the low-level code.

Kubernetes: The Bedrock of Modern Applications

Enterprise application development has evolved over the years - from juggling workloads between physical servers and Virtual Machines to lean containers that split an application into modular components.

These distributed, indefinitely scalable applications have become a staple need, catering to the next generation of flexible, secure architecture. Kubernetes allows you to manage every aspect of a container-based application from a single API, ensuring consistent standards across the board.

Kubernetes is such a widely utilized application that you don’t have to create your K8s application from the ground up. Instead, the leading cloud platforms have integrated K8s into their offerings, often adding their customized tools into the Kubernetes feature set. So whether you use Azure cloud services, AWS, GCP or on-premise hosting, you can start leveraging the power and versatility of Kubernetes right now.