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OpenFunction

OpenFunction is an open-source cloud-native Function-as-a-Service (FaaS) platform that runs on Kubernetes and enables event-driven and serverless workloads using a build-and-run model for functions.

  • FaaS framework on Kubernetes for running event-driven and serverless functions (serverless computing)
  • Build and run separation for functions, supporting multiple builders and runtimes (developer platform)
  • Integration with cloud-native eventing and messaging systems for triggering functions (event-driven architecture)
  • Support for multiple programming languages and frameworks through pluggable runtime images (application runtime)
  • Extensible CRD-based design leveraging Kubernetes APIs and CNCF ecosystem components (cloud-native infrastructure)

More About Openfunction

OpenFunction is an open-source FaaS platform (serverless computing) designed to run on Kubernetes and to support event-driven, serverless application models. It is a Sandbox project under the Cloud Native Computing Foundation (CNCF), and it uses Kubernetes custom resources to define, build, and run functions in a cloud-native manner. The project targets platform engineering, DevOps, and application teams that want to provide serverless capabilities on top of existing Kubernetes clusters.

The core design of OpenFunction separates the function build phase from the function run phase (developer platform). Functions are described as Kubernetes custom resources, and OpenFunction can leverage different build backends and runtime images to create containerized artifacts from source code. This approach aligns with container-native workflows and allows integration with a range of build technologies exposed through the project’s configuration. Once built, functions are deployed as Kubernetes workloads managed through the OpenFunction control plane.

OpenFunction focuses on event-driven function execution (event-driven architecture). Functions can be triggered by events from various sources, including messaging systems and other cloud-native eventing components referred to in the project documentation. The platform defines event sources and triggers using Kubernetes-style resources so that event wiring is managed declaratively. This enables use cases such as asynchronous processing, data pipelines, and integration tasks within a Kubernetes environment.

The runtime model in OpenFunction supports multiple programming languages and frameworks via pluggable runtime images (application runtime). Developers can write functions in supported languages and rely on prebuilt or custom runtime containers that implement the function execution interface. This decouples language choices from the underlying orchestration and scaling logic that Kubernetes provides. The platform can leverage native Kubernetes capabilities for scaling and lifecycle management of function workloads.

From an enterprise perspective, OpenFunction fits into the Kubernetes platform layer as a serverless abstraction running inside existing clusters (cloud-native infrastructure). It interoperates with broader CNCF ecosystem projects referenced in its documentation, using them for eventing, observability, and other supporting services where configured. Because it is based on Kubernetes custom resource definitions (CRDs), OpenFunction can be managed with the same GitOps, policy, and security tooling already in place for cluster operations, which aligns with common enterprise operating models for multi-tenant platforms.

In a technical directory or taxonomy, OpenFunction can be categorized under serverless platforms, Kubernetes-native FaaS frameworks, and event-driven computing. Its emphasis on declarative configuration, build-and-run separation, and ecosystem integration places it in the category of Internal Developer Platform (IDP) components that expose functions as a deployment and execution primitive on Kubernetes.