Using the metal provider extension with Gardener as end-user

The core.gardener.cloud/v1beta1.Shoot resource declares a few fields that are meant to contain provider-specific configuration.

This document describes the configurable options for metal and provides an example Shoot manifest with minimal configuration that can be used to create an metal cluster (modulo the landscape-specific information like cloud profile names, secret binding names, etc.).

metal Provider Credentials

In order for Gardener to create a Kubernetes cluster using the metal infrastructure components, a Shoot has to provide credentials with sufficient permissions to the desired metal project.

In the metal provider extension the infrastructure credential secret has to contain the following components: namespace which is the namespace in the corresponding metal cluster, username which is the name of the ServiceAccount in the metal cluster and a token which is the token generated for the ServiceAccount. An example secret is shown below:

apiVersion: v1
kind: Secret
metadata:
  name: my-credentials 
  namespace: garden-dev
type: Opaque
data:
  namespace: my-metal-namespace
  token: abcd1234
  username: my-serviceaccount-user

InfrastructureConfig

The infrastructure configuration mainly describes how the network layout looks like in order to create the shoot worker nodes in a later step, thus, prepares everything relevant to create VMs, load balancers, volumes, etc.

An example InfrastructureConfig for the metal extension looks as follows:

apiVersion: metal.provider.extensions.gardener.cloud/v1alpha1
kind: InfrastructureConfig
networkRef:
  name: "my-network"
prefixRef:
  name: "my-prefix"

Here the networkRef field refer to network and prefixRef field refer to prefix. Both are used for Shoot creation.

ControlPlaneConfig

The control plane configuration mainly contains values for the metal specific control plane components. Today, the only components deployed by the metal extension is the cloud-controller-manager and the metal-csi-driver.

An example ControlPlaneConfig for the metal extension looks as follows:

apiVersion: metal.provider.extensions.gardener.cloud/v1alpha1
kind: ControlPlaneConfig
cloudControllerManager:
  featureGates:
    CustomResourceValidation: true

The cloudControllerManager.featureGates contains a map of explicitly enabled or disabled feature gates. For production usage it's not recommend to use this field at all as you can enable alpha features or disable beta/stable features, potentially impacting the cluster stability. If you don't want to configure anything for the cloudControllerManager simply omit the key in the YAML specification.

WorkerConfig

At this moment the metal extension does not have any worker specific provider configuration.

Example Shoot manifest

An example to a Shoot manifest here:

CSI volume provisioners

Every metal Shoot cluster will be deployed with the metal-csi-driver.