What is Kubernetes and how does it work? Details about Kubernetes in 2025

What is Kubernetes?

Kubernetes, often abbreviated as K8s (representing the eight letters between “K” and “S”), is an open-source platform that orchestrates and manages containerized applications across diverse environments, including private, public, and hybrid clouds. Organizations leverage Kubernetes to support microservices-based architectures, and it is compatible with most major cloud providers for container deployment.

Application developers, IT administrators, and DevOps teams use Kubernetes to efficiently deploy, scale, manage, schedule, and operate multiple application containers across clusters of nodes. These containers share a host machine’s operating system (OS) but remain isolated from one another unless specifically connected.

What does Kubernetes do?

Kubernetes automates and schedules tasks throughout the application lifecycle, encompassing the following:

• Deployment: Kubernetes deploys containers to designated hosts and ensures they stay operational in a specified state.
• Rollouts: A rollout, representing changes in deployment, can be started, paused, resumed, or rolled back through Kubernetes.
• Service Discovery: With Kubernetes, containers can be automatically accessible over the internet or by other containers through a DNS name or IP address.
• Storage Provisioning: Kubernetes can mount both local and cloud storage to containers as required.
• Load Balancing: Kubernetes distributes workloads across the network based on CPU or other metrics, optimizing performance and stability.
• Autoscaling: To manage traffic spikes, Kubernetes can automatically scale up by creating new clusters to accommodate increased demand.
• Self-healing for High Availability: Kubernetes restarts or replaces failed containers to avoid downtime, removing those that don’t meet health standards.

How Does Kubernetes Work?

Kubernetes organizes containers across multiple networked machines, forming a cluster. Each machine, whether physical or virtual, acts as a node in this cluster. Worker nodes are responsible for hosting containers within pods, all coordinated by the control plane, which is usually hosted on a dedicated machine or group of machines.

The control plane offers the Kubernetes API, accessible directly, through the command-line tool (kubectl), or via other programs to configure the cluster. Kubernetes then automatically deploys containers onto the worker nodes, optimizes resource usage, monitors container health, and replaces any failed or unresponsive pods as needed.

Unlike traditional server or VM management, there’s little need to directly interact with individual nodes in a Kubernetes cluster. Kubernetes decouples applications from the underlying infrastructure, treating pods as temporary, replaceable entities.

What are the components of Kubernetes?

Kubernetes is structured around clusters, nodes, and the control plane. A cluster is composed of nodes, each containing one or more worker machines that host pods for application elements. The control plane manages nodes and pods across potentially multiple computers to ensure high availability.

The control plane includes:

• Kubernetes API server: Provides the API for managing Kubernetes operations.
• etcd: A distributed key-value store holding cluster data.
• Kubernetes scheduler: Assigns new pods to available nodes.
• Kubernetes controller manager: Oversees tasks such as managing node failure, replication control, service linking, and access token handling.
• Cloud controller manager: Handles APIs specific to cloud providers for features like load balancing and infrastructure routes.

Node components include:

• kubelet: An agent ensuring containers within pods are running correctly.
• Kubernetes network proxy: Manages network rules and connectivity.
• Container runtime (e.g., Docker or containerd): Executes the containers.

Benefits of Kubernetes

Kubernetes offers several advantages, including:

• Efficiency: Maximizes resource use, leading to cost savings.
• Reliability: Maintains high availability of application services without downtime.
• Flexibility and Portability: Supports a variety of workloads, including stateless, stateful, and data-processing, and can run on physical machines, virtual machines, and cloud infrastructure.
• Security and Resource Management: Offers strong security features and optimizes resource allocation to enhance infrastructure security and efficiency.
• Support for Various Container Technologies: Works well with Docker and other container platforms, providing versatile containerization options.
• Open-source Community: As an open-source project, Kubernetes is continuously improved by a vast community of contributors and users.

Challenges of using Kubernetes

Kubernetes implementation frequently necessitates adjustments in roles and responsibilities within IT departments as organizations evaluate their storage options, whether utilizing public cloud services or on-premises servers. The challenges associated with Kubernetes can differ significantly based on factors such as the organization’s scale, employee count, scalability needs, and existing infrastructure.

Common challenges with Kubernetes include:

• Complex Self-Management: Some organizations prefer the autonomy of managing open-source Kubernetes independently, provided they have the necessary expertise and resources. Conversely, many opt for service packages from the wider Kubernetes ecosystem to ease deployment and management burdens on their IT teams.
• Scaling Issues: Different components of containerized applications may scale inconsistently under varying loads, which relates more to the application’s architecture than to the container deployment strategy itself. Organizations must strategize on effectively balancing pods and nodes.
• Increased Complexity from Distribution: While distributing application components across containers allows for flexible scaling, an excess of distributed components can lead to heightened complexity, potentially impacting network latency and overall availability.
• Monitoring Challenges: As organizations broaden their use of container orchestration for production workloads, gaining visibility into system performance becomes increasingly difficult. This necessitates enhanced monitoring capabilities across various layers of the Kubernetes architecture to ensure both performance and security.
• Security Considerations: Introducing containers into production environments raises multiple security and compliance challenges, including code vulnerability assessments, multi-factor authentication, and managing multiple stateless configuration requests. Adequate configuration and access control are vital as adoption grows; for instance, Kubernetes initiated a bug bounty program in 2020 to incentivize the discovery of security flaws within its core platform.
• Vendor Lock-In Risks: Despite being an open-source platform, using managed Kubernetes services from cloud providers can lead to vendor lock-in challenges. Transitioning from one managed service to another or managing multi-cloud deployments can introduce significant complexities.

Kubernetes vs. Docker

Kubernetes complements Docker rather than replacing it, although it does supersede certain higher-level technologies developed around Docker.

One such technology is Docker Swarm mode, which manages a cluster of Docker engines known as a “swarm”—a basic orchestration system. While organizations can still opt for Docker Swarm mode instead of Kubernetes, Docker Inc. has integrated Kubernetes as a central feature of its support offerings.

On a smaller scale, Docker also provides Docker Compose, which allows users to launch multi-container applications on a single host. For those who wish to run a multi-container application on one machine without distributing it across a cluster, Docker Compose is the appropriate solution.

Kubernetes is considerably more intricate than either Docker Swarm mode or Docker Compose and demands more effort for deployment. However, this investment is aimed at achieving substantial long-term benefits—creating a more manageable and resilient application infrastructure in production. For development tasks and smaller container clusters, Docker Swarm mode offers a more straightforward option, while Docker Compose is ideal for single-machine deployments of multi-container applications.

Kubernetes Use Cases

Enterprise organizations leverage Kubernetes to address various use cases that are essential to modern IT infrastructure:

• Microservices Architecture or Cloud-Native Development: Cloud-native development focuses on building, deploying, and managing applications that operate in the cloud. The primary advantage of this approach is that it enables DevOps teams to write code once and deploy it across any cloud infrastructure from different service providers. This methodology relies on microservices—where applications consist of numerous loosely coupled, independently deployable components managed in containers by Kubernetes. Kubernetes ensures each microservice has the necessary resources for effective operation while reducing the operational burden of manually managing multiple containers.
• Hybrid Multicloud Environments: Hybrid cloud integrates public cloud, private cloud, and on-premises data center resources into a cohesive and flexible IT infrastructure. Today, hybrid clouds often merge with multicloud strategies that utilize services from multiple cloud vendors, resulting in hybrid multicloud environments. This approach enhances flexibility and mitigates dependency on any single vendor, thus preventing vendor lock-in. Kubernetes serves as the backbone for cloud-native development, making it critical for hybrid multicloud adoption.
• Applications at Scale: Kubernetes facilitates large-scale deployment of cloud applications with autoscaling capabilities. This feature enables applications to automatically adjust their size based on demand fluctuations with speed and efficiency while minimizing downtime. The elastic scalability provided by Kubernetes allows resources to be dynamically added or removed in response to changes in user traffic, such as during flash sales on retail websites.
• Application Modernization: Kubernetes offers the modern cloud platform necessary for application modernization, enabling the migration and transformation of monolithic legacy applications into cloud-native applications built on microservices architecture.
• DevOps Practices: Automation lies at the heart of DevOps, accelerating the delivery of high-quality software by merging and automating the efforts of development and IT operations teams. Kubernetes aids DevOps teams in rapidly building and updating applications by automating their configuration and deployment.
• Artificial Intelligence (AI) and Machine Learning (ML): The ML models and large language models (LLMs) that underpin AI include components that can be challenging and time-consuming to manage independently. By automating configuration, deployment, and scalability across cloud environments, Kubernetes provides the agility needed to train, test, and deploy these complex models efficiently.

How to Get Started with Kubernetes

For those interested in getting started with Kubernetes, here are some recommended steps:

1. Learn the Basics: Gain familiarity with container technologies like Docker before diving into Kubernetes.

2. Set Up a Local Environment: Utilize tools such as Minikube or Kind to create a local Kubernetes cluster for experimentation.

3. Explore Kubernetes Objects: Understand essential Kubernetes objects like Pods, Deployments, Services, and K8 Ingress.

4. Practice with kubectl: Become proficient with kubectl, the command-line interface used to interact with Kubernetes clusters.

5. Explore Helm: Investigate Helm, a package manager for Kubernetes that simplifies deploying complex applications.

6. Consider Managed Kubernetes Services: For production environments, evaluate managed Kubernetes services from cloud providers to streamline cluster management and maintenance.