Describing Kyma in Relation to Kubernetes

Project Kyma was started in 2017 and is still under active development. It is hosted on GitHub and licensed under the Apache 2.0 license. SAP is the main contributor.

Kyma combines the power of Kubernetes with best-in-class tools and open-source projects. These features are provided by building blocks called Kyma modules. From a set of modules, you can choose which ones you want to add to your cluster. By selecting those that suit your needs, you create a customized setup that enables you to develop, run, and operate secure and scalable cloud-native applications.

One important aspect of Kyma is that it is based on the Kubernetes Operator pattern. When you add a Kyma module, its APIs are registered in Kubernetes as CustomResourceDefinitions (CRDs). CRDs serve as the foundation for custom resources (CRs), which you can create to define and manage your own custom objects. This allows you to use native Kubernetes tools like kubectl to manage Kyma resources. Furthermore, each Kyma module includes an operator that handles the management and reconciliation of the module based on the information provided in the module's CR.

See the overview of Kyma modules:

In fact, Kyma also comes with its own command-line interface (CLI) called Kyma CLI. However, Kyma CLI is not used in this learning journey.

Let's take a closer look at the modules that you can add to your Kyma runtime instance:

Istio

The Istio module is responsible for installing Istio - a service mesh that provides a uniform way to manage, connect, and secure microservices. A service mesh is a network of microservices that can communicate with each other. It is also responsible for the security of the communication between the microservices, such as your Pods or Functions. It can also provide additional features like traffic management, circuit breaking, and load balancing. Kyma uses the open-source Istio service mesh. This also comes with out-of-the-box metrics, which can be used to gather various information about your services.

API Gateway

The API Gateway module provides a single point of entry for all external communication from your Kubernetes cluster. It is also responsible for the security of the communication.

SAP BTP Operator

The SAP BTP Operator module allows you to connect SAP BTP services to your Kubernetes cluster and manage them using Kubernetes-native tools.

Application Connector

The Application Connector module simplifies and secures the connection between external solutions and Kyma. No matter if you want to integrate an on-premise or a cloud system, the integration process doesn't change, which allows you to avoid any configuration or network-related problems. The module stores and handles the metadata of external APIs, offers monitoring and tracing capabilities and provides certificate handling for the Eventing flow.

Cloud Manager

The Cloud Manager module module manages access to cloud providers' chosen resources and products. Once you add Cloud Manager to your Kyma cluster, the module securely brings the offered resources. Cloud Manager is strictly coupled with the cloud provider where your Kyma cluster is deployed. It offers such features as Network File System (NFS) server, Virtual Private Cloud (VPC) peering, or Redis.

Keda

The Keda module enables you to easily install and manage the Kubernetes-based Event Driven Autoscaler (KEDA) on your Kubernetes cluster. KEDA is an autoscaler that allows you to easily scale your Kubernetes workloads based on the triggers you choose. With KEDA, you have access to a variety of scalers that help you efficiently manage your deployments.

Eventing

The Eventing module enables users to focus on their business workflows and trigger them with events, simplifying the process of publishing and subscribing to events. With Eventing, users can implement asynchronous flows within Kyma without implementing or integrating any additional backend or protocol.

NATS

The NATS module manages the deployment of NATS JetStream, a distributed persistence system that enhances the functionality and quality of the NATS service. The module ensures that the NATS cluster is in the desired state by observing its state and performing reconciliation. Kyma Eventing can utilize NATS as a backend to handle events and deliver them to subscribers.

Serverless

The Serverless module of Kyma provides a set of tools to develop, run, and scale serverless Functions. Serverless or serverless computing doesn't mean that there is no server attached at all. Instead, it abstracts the server away from the developer. The developer can focus on the code and the business logic.

Telemetry

As a key aspect of service-oriented architecture, you may want to monitor the behaviour of a system by collecting and analyzing metrics, logs, and traces. This data is used to identify and diagnose problems in the system. The Telemetry module provides a set of tools to collect, enrich, and analyze such data. These tools are based on open-source projects like OpenTelemetry and Fluent Bit.

Open-Source Project "Kyma"

SAP BTP, Kyma Runtime