What is Kubernetes?

Kubernetes: definition and purpose

Containers package an application together with its dependencies into a uniform bundle. Once many such containers run on several servers, management becomes laborious: who starts them, who distributes the load, who replaces a crashed container? Kubernetes, often abbreviated K8s, handles exactly this orchestration.

The platform was originally developed by Google and is now maintained by the Cloud Native Computing Foundation. It is open source and vendor-neutral. Almost all major cloud providers offer Kubernetes as a managed service, so companies do not have to deal with the technology of the control plane.

How Kubernetes works

A Kubernetes cluster consists of several servers, the nodes, and a control plane. In configuration files, you describe the desired state, such as “three instances of this application.” Kubernetes constantly compares desired and actual state and steps in when a container fails or a server stops responding.

The smallest unit is the pod, in which one or more containers run. Services make pods reachable at a fixed address and distribute requests, and an ingress forwards web traffic from outside. As load rises, the platform can start additional instances and roll out new versions step by step (rolling update).

Real-world example: a software company with an online industry solution

A mid-sized software company runs an industry application as an online service for many customers. It consists of several services: user management, invoicing, interfaces and reports. Each runs as its own container, and at the start of the month, when many invoices are generated, the invoicing service needs considerably more capacity.

Kubernetes starts additional instances for this and shuts them down again after the peak. New program versions are rolled out without interrupting operations, and if a server fails, others take over its tasks. For the same company’s plain corporate website, such an effort would be excessive and uneconomical.

Benefits, limits and common mistakes

Kubernetes offers self-healing, automatic scaling and consistent operation across different environments. The price is complexity: setup, security, networking, storage and updates require expertise. A typical mistake is introducing Kubernetes when a single application on a managed server or a PaaS platform would be entirely sufficient.

Nano Concepts advises independently on whether Kubernetes makes sense for your project, sets up clusters or uses managed offerings from cloud providers and, if you wish, takes over operation, updates, monitoring and security. That way you benefit from the technology without building a team of specialists of your own.

• Makes sense with several services, fluctuating load and frequent updates
• Usually too big for individual websites or small applications
• Managed Kubernetes offerings significantly reduce operating effort
• Version configuration as code in Git
• Plan access rights, network rules and updates from the start