NFD-Master

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NFD-Master is responsible for connecting to the Kubernetes API server and updating node objects. More specifically, it modifies node labels, taints and extended resources based on requests from nfd-workers and 3rd party extensions.

NodeFeature controller

The NodeFeature Controller uses NodeFeature objects as the input for the NodeFeatureRule processing pipeline. In addition, any labels listed in the NodeFeature object are created on the node (note the allowed label namespaces are controlled).

NodeFeatureRule controller

NFD-Master acts as the controller for NodeFeatureRule objects. It applies the rules specified in NodeFeatureRule objects on raw feature data and creates node labels accordingly. The feature data used as the input is received from nfd-worker instances through NodeFeature objects.

Master configuration

NFD-Master supports configuration through a configuration file. The default location is /etc/kubernetes/node-feature-discovery/nfd-master.conf, but, this can be changed by specifying the-config command line flag.

Master configuration file is read inside the container, and thus, Volumes and VolumeMounts are needed to make your configuration available for NFD. The preferred method is to use a ConfigMap which provides easy deployment and re-configurability.

The provided deployment methods (Helm and Kustomize) create an empty configmap and mount it inside the nfd-master containers.

In Helm deployments, Master pod parameter master.config can be used to edit the respective configuration.

In Kustomize deployments, modify the nfd-master-conf ConfigMap with a custom overlay.

NOTE: dynamic run-time reconfiguration was dropped in NFD v0.17. Re-configuration is handled by pod restarts.

See nfd-master configuration file reference for more details. The (empty-by-default) example config contains all available configuration options and can be used as a reference for creating a configuration.

Deployment notes

NFD-Master runs as a deployment, by default it prefers running on the cluster's master nodes but will run on worker nodes if no master nodes are found.

For High Availability, you should increase the replica count of the deployment object. You should also look into adding inter-pod affinity to prevent masters from running on the same node. However note that inter-pod affinity is costly and is not recommended in bigger clusters.

Note: When NFD-Master is intended to run with more than one replica, it is advised to use -enable-leader-election flag. This flag turns on leader election for NFD-Master and let only one replica to act on changes in NodeFeature and NodeFeatureRule objects.

If you have RBAC authorization enabled (as is the default e.g. with clusters initialized with kubeadm) you need to configure the appropriate ClusterRoles, ClusterRoleBindings and a ServiceAccount for NFD to create node labels. The provided template will configure these for you.