# CRDs Catalog

This repository aggregates over 100 popular Kubernetes CRDs (`CustomResourceDefinition`) in JSON schema format. These schemas can be used by various tools such as [Datree](https://github.com/datreeio/datree), [Kubeconform](https://github.com/yannh/kubeconform) and [Kubeval](https://github.com/instrumenta/kubeval), as an alternative to `kubectl --dry-run`, to perform validation on custom (and native) Kuberentes resources.  

Running Kubernetes schema validation checks helps apply the **"shift-left approach"** on machines **without** giving them access to your cluster (e.g. locally or on CI).

## How to use the schemas in the catalog
### Datree
```
datree test [MANIFEST]
```
### Kubeconform
```
kubeconform -schema-location default -schema-location 'https://raw.githubusercontent.com/datreeio/CRDs-catalog/main/{{.Group}}/{{.ResourceKind}}_{{.ResourceAPIVersion}}.json' [MANIFEST]
```
### kubeval
```
Only supported with the CRD Extractor
```

👉 If you encounter custom resources that are not part of the catalog, or you want to validate the schemas in an air-gapped environment, use the [CRD Extractor](#crd-extractor). 

## CRD Extractor

This repository also contains a handy utility that extracts all CRDs from a cluster and converts them to JSON schema.

### What does this utility do?
1. Checks that the prerequisites are installed.
2. Extracts your CRDs from your cluster using kubectl.
3. Downloads a script from the [kubeconform](https://github.com/yannh/kubeconform/blob/master/scripts/openapi2jsonschema.py) repo that converts your CRDs from openAPI to JSON schema.
4. Runs the script, and saves the output to your machine under `$HOME/.datree/crdSchemas/`

### Supported Platforms

This utility supports **MacOS** and **Linux**.

### Prerequisites
The following programs are required to be installed on the machine running this utility:
* [python3](https://www.python.org/downloads/)
* [kubectl](https://kubernetes.io/docs/tasks/tools/#kubectl)

### Usage
To use the CRD Extractor:  
1. Download the [latest release](https://github.com/datreeio/CRDs-catalog/releases/latest/download/crd-extractor.zip) from this repository.
2. Extract, and run the utility:
```
./crd-extractor.sh
```

![image](https://user-images.githubusercontent.com/19731161/185790837-2abadcd5-9b26-451b-b3cd-7e0c46c68b58.png)

## Contributing CRDs to the catalog
If the catalog is missing public custom resources (CRs) that you would like to automatically validate using these tools, you can open an issue or use the **[CRD Extractor](#crd-extractor)** to add the schemas to this repository by creating a pull request.

## Resources
* [opensource.com - Why you need to use Kubernetes schema validation tools](https://opensource.com/article/21/7/kubernetes-schema-validation)
* [redhat.com - Validating OpenShift Manifests in a GitOps World](https://cloud.redhat.com/blog/validating-openshift-manifests-in-a-gitops-world)
* [kubeval/issues/47 - cannot validate CustomResourceDefinitions](https://github.com/instrumenta/kubeval/issues/47)
