kinitiras

[中文]

A lightweight but powerful and programmable rule engine for kubernetes admission webhook.

If you want to use it in clientside with client-go, please use pidalio.

Quick Start

Add Helm source

helm repo add k-cloud-labs https://k-cloud-labs.github.io/helm-charts

Install

All resources will be applied to kinitiras-system namespace by default. You can modify the deployment files as your expect.

Pay attention to the deploy/webhook-configuration.yaml file. The default config will mutate and validate all kubernetes resources filtered by label kinitiras.kcloudlabs.io/webhook: enabled.

YOU NEED TO UPDATE THE RULES AS YOUR EXPECT TO MINIMIZE THE EFFECTIVE SCOPE OF THE ADMISSION WEBHOOK.

After all changes done, just apply it to your cluster.

helm install kinitiras-webhook k-cloud-labs/kinitiras --namespace kinitiras-system --create-namespace

Create policy

Three kind of policy are supported.

OverridePolicy is used to mutate object in the same namespace.
ClusterOverridePolicy is used to mutate object in any namespace.
ClusterValidatePolciy is used to validate object in any namespace.

For cluster scoped resource:

• Apply ClusterOverridePolicy by policies name in ascending;

For namespaced scoped resource, apply order is:

• First apply ClusterOverridePolicy;
• Then apply OverridePolicy;

Both mutate and validate policy are programmable via CUE.

Constraint

1. The kubernetes object will be passed to CUE by object parameter.
2. The mutating result will be returned by patches parameter.
3. The Validating result will be returned by validate parameter.
4. Use processing to support data passing. It contains http and output schema.
   1. http used to make a http(s) request. Refer to: http
   2. output used to receive response. You should add some properties you need to it.

Schema:

// for input parameter, oldObject only exist in `UPDATE` operation for clustervalidatepolicy 
object: _ @tag(object) 
oldObject: _ @tag(oldObject)

// use processing to pass data. A http reqeust will be make and output contains the response.
processing: {
	output: {
		// add what you need	
	}
	http: {
	    method: *"GET" | string
	    url: parameter.serviceURL
	    request: {
	    	body ?: bytes
	    	header: {}
	    	trailer: {}
	    }
	}
}

patch: {
	op: string
	path: string
	value: string
}

// for mutating result
patches: [...patch] 

// for validating result
validate: { 
	reason?: string
	valid: bool
}

Examples

You can try some examples in the example folder.

The deletens-cvp.yaml will protect the namespace labeled with kinitiras.kcloudlabs.io/webhook=enabled from being deleted.

The addanno-op.yaml will add annotation added-by=op to pod labeled with kinitiras.kcloudlabs.io/webhook=enabled in the default namespace.

The addanno-cop.yaml will add annotation added-by=cue to pod labeled with kinitiras.kcloudlabs.io/webhook=enabled in the default namespace.

Feature

• Support mutate k8s resource by (Cluster)OverridePolicy via plaintext jsonpatch.
• Support mutate k8s resource by (Cluster)OverridePolicy programmable via CUE.
• Support validate k8s resource by ClusterValidatePolicy programmable via CUE.
• Support Data passing by http request via CUE.
• kubectl plugin to validate CUE.
• ...

For more detail information for this project, please read the roadmap.