Node Feature Discovery
This documentation is for Node Feature Discovery version that is no longer supported. Please upgrade and visit the documentation of the latest stable release.

# Deployment and Usage

## Table of Contents

### System requirements

1. Linux (x86_64/Arm64/Arm)
2. kubectl (properly set up and configured to work with your Kubernetes cluster)
3. Docker (only required to build and push docker images)

## Usage

### NFD-Master

NFD-Master runs as a deployment (with a replica count of 1), 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 simply 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.

You can use the template spec provided to deploy nfd-master, or use `nfd-master.yaml` generated by `Makefile`. The latter includes `image:` and `namespace:` definitions that match the latest built image. Example:

    make IMAGE_TAG=<IMAGE_TAG>
    docker push <IMAGE_TAG>
    kubectl create -f nfd-master.yaml

NFD-Master listens for connections from nfd-worker(s) and connects to the Kubernetes API server to add node labels advertised by them.

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 in order for NFD to create node labels. The provided template will configure these for you.

### NFD-Worker

NFD-Worker is preferably run as a Kubernetes DaemonSet. There is an example spec (`nfd-worker-daemonset.yaml.template`) that can be used as a template, or, as is when just trying out the service. Similarly to nfd-master above, the `Makefile` also generates `nfd-worker-daemonset.yaml` from the template that you can use to deploy the latest image. Example:

    make IMAGE_TAG=<IMAGE_TAG>
    docker push <IMAGE_TAG>
    kubectl create -f nfd-worker-daemonset.yaml

NFD-Worker connects to the nfd-master service to advertise hardware features.

When run as a daemonset, nodes are re-labeled at an interval specified using the `--sleep-interval` option. In the template the default interval is set to 60s which is also the default when no `--sleep-interval` is specified. Also, the configuration file is re-read on each iteration providing a simple mechanism of run-time reconfiguration.

Feature discovery can alternatively be configured as a one-shot job. There is an example script in this repo that demonstrates how to deploy the job in the cluster.

    ./label-nodes.sh [<IMAGE_TAG>]

The label-nodes.sh script tries to launch as many jobs as there are Ready nodes. Note that this approach does not guarantee running once on every node. For example, if some node is tainted NoSchedule or fails to start a job for some other reason, then some other node will run extra job instance(s) to satisfy the request and the tainted/failed node does not get labeled.

### NFD-Master and NFD-Worker in the same Pod

You can also run nfd-master and nfd-worker inside a single pod (skip the `sed` part if running the latest released version):

    sed -E s',^(\s*)image:.+$,\1image: <YOUR_IMAGE_REPO>:<YOUR_IMAGE_TAG>,' nfd-daemonset-combined.yaml.template > nfd-daemonset-combined.yaml
    kubectl apply -f nfd-daemonset-combined.yaml

Similar to the nfd-worker setup above, this creates a DaemonSet that schedules an NFD Pod an all worker nodes, with the difference that the Pod also also contains an nfd-master instance. In this case no nfd-master service is run on the master node(s), but, the worker nodes are able to label themselves.

This may be desirable e.g. in single-node setups.

### TLS authentication

NFD supports mutual TLS authentication between the nfd-master and nfd-worker instances. That is, nfd-worker and nfd-master both verify that the other end presents a valid certificate.

TLS authentication is enabled by specifying `--ca-file`, `--key-file` and `--cert-file` args, on both the nfd-master and nfd-worker instances. The template specs provided with NFD contain (commented out) example configuration for enabling TLS authentication.

The Common Name (CN) of the nfd-master certificate must match the DNS name of the nfd-master Service of the cluster. By default, nfd-master only check that the nfd-worker has been signed by the specified root certificate (–ca-file). Additional hardening can be enabled by specifying –verify-node-name in nfd-master args, in which case nfd-master verifies that the NodeName presented by nfd-worker matches the Common Name (CN) of its certificate. This means that each nfd-worker requires a individual node-specific TLS certificate.

## Deployment options

### Deployment Templates

For a stable version with ready-built images see the latest release.

### Build Your Own

If you want to use the latest development version (master branch) you need to build your own custom image. See the Developer Guide for instructions how to build images and deploy them on your cluster.

## Configuration

NFD-Worker supports a configuration file. The default location is `/etc/kubernetes/node-feature-discovery/nfd-worker.conf`, but, this can be changed by specifying the`--config` command line flag. Configuration file is re-read on each labeling pass (determined by `--sleep-interval`) which makes run-time re-configuration of nfd-worker possible.

Worker 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. For example, create a config map using the example config as a template:

    cp nfd-worker.conf.example nfd-worker.conf
    vim nfd-worker.conf  # edit the configuration
    kubectl create configmap nfd-worker-config --from-file=nfd-worker.conf

Then, configure Volumes and VolumeMounts in the Pod spec (just the relevant snippets shown below):

    ...
      containers:
          volumeMounts:
            - name: nfd-worker-config
              mountPath: "/etc/kubernetes/node-feature-discovery/"
    ...
      volumes:
        - name: nfd-worker-config
          configMap:
            name: nfd-worker-config
    ...

You could also use other types of volumes, of course. That is, hostPath if different config for different nodes would be required, for example.

The (empty-by-default) example config is used as a config in the NFD Docker image. Thus, this can be used as a default configuration in custom-built images.

Configuration options can also be specified via the `--options` command line flag, in which case no mounts need to be used. The same format as in the config file must be used, i.e. JSON (or YAML). For example:

    --options='{"sources": { "pci": { "deviceClassWhitelist": ["12"] } } }'

Configuration options specified from the command line will override those read from the config file.

## Using Node Labels

Nodes with specific features can be targeted using the `nodeSelector` field. The following example shows how to target nodes with Intel TurboBoost enabled.

    apiVersion: v1
    kind: Pod
    metadata:
      labels:
        env: test
      name: golang-test
    spec:
      containers:
        - image: golang
          name: go1
      nodeSelector:
        feature.node.kubernetes.io/cpu-pstate.turbo: 'true'

For more details on targeting nodes, see node selection.

Node Feature Discovery
v0.6

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The software is under the terms of Apache License 2.0.