The widespread adoption of the cloud-native model has transformed the landscape of modern software development and deployment. The cloud-native approach is centered around building and running applications designed to fully leverage the capabilities of cloud computing and modern development practices, especially the use of the microservices architecture and containerization and orchestration.

Cloud-native applications are developed using a microservices architecture, where applications are composed of smaller, loosely coupled services, with each service created, deployed, and scaled independently, promoting agility and flexibility.

Each of these microservices is contained within a container, a fundamental technology in the cloud-native model. Containers provide a consistent and isolated environment for applications to run. However, for an application to run correctly, a container orchestration platform like Kubernetes is required to automate container deployment, scaling, and management, making it easier to manage complex applications.

What is Kubernetes?

Kubernetes, also known as K8s, is an open-source container orchestration platform that automates the deployment, scaling, management, and operation of containerized applications. It is built to handle the demands of production environments, offering features like high availability, fault tolerance, scalability, and security.

K8s was initially developed by Google and is now maintained by the Cloud Native Computing Foundation (CNCF). The CNCF is part of the Linux Foundation and is “the open source, vendor-neutral hub of cloud native computing, hosting projects like Kubernetes and Prometheus to make cloud native universal and sustainable.”

In summary, it is correct to conclude that CNCF projects form the essence of cloud-native applications. Therefore, let's start by looking at Kubernetes, a fundamental and widely used technology within the CNCF ecosystem.

The Function and Purpose of Kubernetes

In simple terms, K8s organizes (orchestrates) containers within an application to make them easier to manage, with its primary function being to simplify the management of complex distributed systems by providing a unified platform for deploying and running containerized workloads.

Kubernetes aims to address the challenges associated with deploying and managing applications in modern computing environments, where applications are composed of multiple interconnected components that must be highly available, scalable, and adaptable.

In essence, K8s abstracts the complexities of managing containerized applications in a distributed environment. By automating critical operational tasks and providing a flexible platform for deploying and managing applications, Kubernetes empowers organizations to build and scale cloud-native applications with agility, efficiency, and resilience.

Here is an overview of seven of Kubernetes’ key functions and purposes:

1. Container Management

K8s manages containers encapsulating application code, runtime, libraries, and dependencies, ensuring consistent deployment and execution across different environments.

2. Automated Deployment

Kubernetes automates the deployment process, allowing you to define how your application should be deployed, including the number of replicas, resource requirements, and networking configurations.

3. Scaling and Load Balancing

K8s automates horizontal scaling, increasing or decreasing the number of instances (pods) of an application based on demand. It also balances traffic across instances using built-in load-balancing mechanisms.

4. Self-Healing

Kubernetes continuously monitors the health of application components (pods) and nodes. If a pod or node fails, K8s automatically replaces it with a new instance to ensure high availability and resilience.

5. Configuration Management

K8s separates application configuration from code, enabling you to manage configurations, environment variables, and secrets independently and consistently across environments.

6. Resource Management

K8s manages resources like CPU and memory for containers, ensuring optimal utilization and preventing resource contention among applications.

7. Storage Orchestration

Kubernetes enables dynamic provisioning and management of storage resources for stateful applications, simplifying data storage and management.

Kubernetes: Simplifying Container Orchestration

Now that we have an overview of the function and purpose of Kubernetes, let’s consider the following practical use case, describing how K8s simplifies container orchestration in real-world scenarios.

Before we continue, it is worth noting that Stephen Watts of Splunk.com reports that applications using Kubernetes and containers like Docker have increased by more than 300% in the last six years. Additionally, he cites a 2022 survey conducted by the CNCF, whose key finding is that:

“A record high of 96% of organizations [surveyed] are either using Kubernetes or evaluating it - a major increase from 83% in 2020 and 78% in 2019.”

Imagine you own an eCommerce business, are participating in the annual Black Friday sale event, and expect a sudden spike in traffic. To handle this surge in demand, you need to dynamically scale the application while ensuring high availability and minimizing downtime.

Note: When the Black Friday sale is over, traffic volumes will likely drop to their pre-sale levels; therefore, using Kubernetes before and after the sale has merit, as described below.

1. Containerize Application

The first step is to ensure that your eCommerce application is containerized using Docker containers. Each component of the application, like the frontend, backend, and database, is packaged into separate containers.

2. Deploy Kubernetes

Deploy your containerized application on a K8s cluster. Kubernetes abstracts the underlying infrastructure and provides a declarative approach to define how your application infrastructure must be deployed.

Note: A declarative rather than imperative approach is a fundamental concept in Infrastructure-as-Code models. You define the desired state of your infrastructure without specifying the step-by-step instructions to achieve this state. In other words, you declare what the infrastructure should look like, and Kubernetes is responsible for making it work.

3. Load Balancing and Scaling

Set up a Kubernetes Service that acts as a load balancer, distributing incoming traffic across multiple application instances. Secondly, define a Kubernetes Deployment, specifying each container's desired number of replicas (pods).

4. Auto-Scaling

Configure K8s to automatically scale the number of pods based on CPU utilization using Kubernetes Horizontal Pod Auto-Scaling (HPA). As traffic increases, Kubernetes detects the higher load and creates additional pods to handle it.

5. Self-Healing

K8s constantly monitors the health of the application’s pods. If a pod becomes unhealthy because it crashed (or has other issues), Kubernetes automatically terminates it and replaces it with a new pod, ensuring interrupted service.

6. Efficient Resource Usage

K8s allocates resources like CPU and memory for each pod based on your defined limits and requests, preventing resource contention and ensuring efficient utilization.

In Conclusion

In this practical use case (and the theory described above), it is clear how Kubernetes facilitates and simplifies container orchestration. It automates the functions such as scaling, load balancing, and self-healing, reducing the manual effort required to manage a cloud-native application during high-demand periods. As a result, you can efficiently handle traffic spikes, provide a seamless shopping experience to users, and focus on delivering value rather than infrastructure management.