github.com/wmuizelaar/kpt@v0.0.0-20221018115725-bd564717b2ed/site/book/02-concepts/00.md (about) 1 What is kpt? 2 3 > kpt automates Kubernetes configuration editing. 4 5 kpt supports management of [Configuration as Data](https://github.com/GoogleContainerTools/kpt/blob/main/docs/design-docs/06-config-as-data.md). 6 7 *Configuration as Data* is an approach to management of configuration which: 8 9 * makes configuration data the source of truth, stored separately from the live 10 state 11 * uses a uniform, serializable data model to represent configuration 12 * separates code that acts on the configuration from the data and from packages 13 / bundles of the data 14 * abstracts configuration file structure and storage from operations that act 15 upon the configuration data; clients manipulating configuration data don’t 16 need to directly interact with storage (git, container images) 17 18 This enables machine manipulation of configuration for Kubernetes and any infrastructure represented 19 in the [Kubernetes Resource Model (KRM)](https://github.com/kubernetes/design-proposals-archive/blob/main/architecture/resource-management.md). 20 21 kpt manages KRM resources in bundles called **packages**. 22 23 Off-the-shelf packages are rarely deployed without any customization. Like [kustomize](https://kustomize.io), kpt applies transformation **functions**, using the same [KRM function specification](https://github.com/kubernetes-sigs/kustomize/blob/master/cmd/config/docs/api-conventions/functions-spec.md), but optimizes for in-place configuration transformation rather than out-of-place transformation. 24 25 Validation goes hand-in-hand with customization and kpt functions can be used to automate both mutation and validation of resources, similar to [Kubernetes admission control](https://kubernetes.io/docs/reference/access-authn-authz/extensible-admission-controllers/). 26 27 The kpt toolchain includes the following components: 28 29 - [**kpt CLI**](https://kpt.dev/reference/cli/): The kpt CLI supports package and function operations, and also 30 deployment, via either direct apply or GitOps. By keeping an inventory of deployed resources, kpt enables resource pruning, 31 aggregated status and observability, and an improved preview experience. 32 33 - **Function SDKs**: Any general-purpose or domain-specific language can be used to create functions to transform and/or validate 34 the YAML KRM input/output format, but we provide SDKs to simplify the function authoring process, in 35 [Go](https://kpt.dev/book/05-developing-functions/02-developing-in-Go), 36 [Typescript](https://kpt.dev/book/05-developing-functions/03-developing-in-Typescript), and 37 [Starlark](https://kpt.dev/book/05-developing-functions/04-developing-in-Starlark), a Python-like embedded language. 38 39 - [**Function catalog**](https://catalog.kpt.dev/): A catalog of off-the-shelf, tested functions. kpt makes configuration 40 easy to create and transform, via reusable functions. Because they are expected to be used for in-place transformation, 41 the functions need to be idempotent. 42 43 - [**Package orchestrator**](https://github.com/GoogleContainerTools/kpt/blob/main/docs/design-docs/07-package-orchestration.md): 44 The package orchestrator enables the magic behind the unique WYSIWYG experience. It provides a control plane for creating, 45 modifying, updating, and deleting packages, and evaluating functions on package data. This enables operations on packaged resources 46 similar to operations directly on the live state through the Kubernetes API. 47 48 - [**Config Sync**](https://cloud.google.com/anthos-config-management/docs/config-sync-overview): While the package orchestrator 49 can be used with any GitOps tool, Config Sync provides a reference GitOps implementation to complete the WYSIWYG management 50 experience and enable end-to-end development of new features, such as 51 [OCI-based packages](https://github.com/GoogleContainerTools/kpt/issues/2300). Config Sync is also helping to drive improvements 52 in upstream Kubernetes. For instance, Config Sync is built on top of [git-sync](https://github.com/kubernetes/git-sync) and 53 leverages [Kustomize](https://kustomize.io) to automatically render manifests on the fly when needed. It uses the same apply 54 logic as the kpt CLI. 55 56 - **Backstage UI plugin**: We've created a proof-of-concept UI to demonstrate the WYSIWYG experience that's possible on top of the 57 package orchestrator. More scenarios can be supported by implementing form-based editors for additional Kubernetes resource types. 58