node-feature-discovery/docs/advanced/developer-guide.md

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Developer guide	default	1

Developer guide

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Building from source

Download the source code

git clone https://github.com/kubernetes-sigs/node-feature-discovery
cd node-feature-discovery

Docker build

Build the container image

See customizing the build below for altering the container image registry, for example.

make

Push the container image

Optional, this example with Docker.

docker push <IMAGE_TAG>

Change the job spec to use your custom image (optional)

To use your published image from the step above instead of the k8s.gcr.io/nfd/node-feature-discovery image, edit image attribute in the spec template(s) to the new location (<registry-name>/<image-name>[:<version>]).

Deployment

The yamls makefile generates a kustomization.yaml matching your locally built image and using the deploy/overlays/default deployment. See build customization below for configurability, e.g. changing the deployment namespace.

K8S_NAMESPACE=my-ns make yamls
kubectl apply -k .

You can use alternative deployment methods by modifying the auto-generated kustomization file. For example, deploying worker and master in the same pod by pointing to deployment/overlays/default-combined.

Building locally

You can also build the binaries locally

make build

This will compile binaries under bin/

Customizing the build

There are several Makefile variables that control the build process and the name of the resulting container image. The following are targeted targeted for build customization and they can be specified via environment variables or makefile overrides.

Variable	Description	Default value
HOSTMOUNT_PREFIX	Prefix of system directories for feature discovery (local builds)	/ (local builds) /host- (container builds)
IMAGE_BUILD_CMD	Command to build the image	docker build
IMAGE_BUILD_EXTRA_OPTS	Extra options to pass to build command	empty
IMAGE_PUSH_CMD	Command to push the image to remote registry	docker push
IMAGE_REGISTRY	Container image registry to use	k8s.gcr.io/nfd
IMAGE_TAG_NAME	Container image tag name	<nfd version>
IMAGE_EXTRA_TAG_NAMES	Additional container image tag(s) to create when building image	empty
K8S_NAMESPACE	nfd-master and nfd-worker namespace	kube-system
KUBECONFIG	Kubeconfig for running e2e-tests	empty
E2E_TEST_CONFIG	Parameterization file of e2e-tests (see example)	empty
OPENSHIFT	Non-empty value enables OpenShift specific support (currently only effective in e2e tests)	empty
BASE_IMAGE_FULL	Container base image for target image full (--target full)	debian:buster-slim
BASE_IMAGE_MINIMAL	Container base image for target image minimal (--target minimal)	gcr.io/distroless/base

For example, to use a custom registry:

make IMAGE_REGISTRY=<my custom registry uri>

Or to specify a build tool different from Docker, It can be done in 2 ways:

1. via environment

   IMAGE_BUILD_CMD="buildah bud" make
   

2. by overriding the variable value

   make  IMAGE_BUILD_CMD="buildah bud"
   

Testing

Unit tests are automatically run as part of the container image build. You can also run them manually in the source code tree by simply running:

make test

End-to-end tests are built on top of the e2e test framework of Kubernetes, and, they required a cluster to run them on. For running the tests on your test cluster you need to specify the kubeconfig to be used:

make e2e-test KUBECONFIG=$HOME/.kube/config

Running locally

You can run NFD locally, either directly on your host OS or in containers for testing and development purposes. This may be useful e.g. for checking features-detection.

NFD-Master

When running as a standalone container labeling is expected to fail because Kubernetes API is not available. Thus, it is recommended to use -no-publish command line flag. E.g.

$ export NFD_CONTAINER_IMAGE={{ site.container_image }}
$ docker run --rm --name=nfd-test ${NFD_CONTAINER_IMAGE} nfd-master -no-publish
2019/02/01 14:48:21 Node Feature Discovery Master <NFD_VERSION>
2019/02/01 14:48:21 gRPC server serving on port: 8080

Command line flags of nfd-master:

$ docker run --rm ${NFD_CONTAINER_IMAGE} nfd-master -help
Usage of nfd-master:
  -ca-file string
        Root certificate for verifying connections
  -cert-file string
        Certificate used for authenticating connections
  -extra-label-ns value
        Comma separated list of allowed extra label namespaces
  -instance string
        Instance name. Used to separate annotation namespaces for multiple parallel deployments.
  -key-file string
        Private key matching -cert-file
  -kubeconfig string
        Kubeconfig to use
  -label-whitelist value
        Regular expression to filter label names to publish to the Kubernetes API server. NB: the label namespace is omitted i.e. the filter is only applied to the name part after '/'.
  -no-publish
        Do not publish feature labels
  -port int
        Port on which to listen for connections. (default 8080)
  -prune
        Prune all NFD related attributes from all nodes of the cluaster and exit.
  -resource-labels value
        Comma separated list of labels to be exposed as extended resources.
  -verify-node-name
        Verify worker node name against the worker's TLS certificate. Only takes effect when TLS authentication has been enabled.
  -version
        Print version and exit.

NFD-Worker

In order to run nfd-worker as a "stand-alone" container against your standalone nfd-master you need to run them in the same network namespace:

$ docker run --rm --network=container:nfd-test ${NFD_CONTAINER_IMAGE} nfd-worker
2019/02/01 14:48:56 Node Feature Discovery Worker <NFD_VERSION>
...

If you just want to try out feature discovery without connecting to nfd-master, pass the -no-publish flag to nfd-worker.

Command line flags of nfd-worker:

$ docker run --rm ${NFD_CONTAINER_IMAGE} nfd-worker -help
Usage of nfd-worker:
  -ca-file string
        Root certificate for verifying connections
  -cert-file string
        Certificate used for authenticating connections
  -config string
        Config file to use. (default "/etc/kubernetes/node-feature-discovery/nfd-worker.conf")
  -key-file string
        Private key matching -cert-file
  -label-whitelist value
        Regular expression to filter label names to publish to the Kubernetes API server. NB: the label namespace is omitted i.e. the filter is only applied to the name part after '/'. DEPRECATED: This parameter should be set via the config file.
  -no-publish
        Do not publish discovered features, disable connection to nfd-master.
  -oneshot
        Do not publish feature labels
  -options string
        Specify config options from command line. Config options are specified in the same format as in the config file (i.e. json or yaml). These options
  -server string
        NFD server address to connecto to. (default "localhost:8080")
  -server-name-override string
        Hostname expected from server certificate, useful in testing
  -sleep-interval duration
        Time to sleep between re-labeling. Non-positive value implies no re-labeling (i.e. infinite sleep). DEPRECATED: This parameter should be set via the config file
  -sources value
        Comma separated list of feature sources. Special value 'all' enables all feature sources. DEPRECATED: This parameter should be set via the config file
  -version
        Print version and exit.

NOTE Some feature sources need certain directories and/or files from the host mounted inside the NFD container. Thus, you need to provide Docker with the correct --volume options in order for them to work correctly when run stand-alone directly with docker run. See the default deployment for up-to-date information about the required volume mounts.

NFD-Topology-Updater

In order to run nfd-topology-updater as a "stand-alone" container against your standalone nfd-master you need to run them in the same network namespace:

$ docker run --rm --network=container:nfd-test ${NFD_CONTAINER_IMAGE} nfd-topology-updater
2019/02/01 14:48:56 Node Feature Discovery Topology Updater <NFD_VERSION>
...

If you just want to try out feature discovery without connecting to nfd-master, pass the -no-publish flag to nfd-topology-updater.

Command line flags of nfd-topology-updater:

$ docker run --rm ${NFD_CONTAINER_IMAGE} nfd-topology-updater -help
docker run --rm  quay.io/swsehgal/node-feature-discovery:v0.10.0-devel-64-g93a0a9f-dirty nfd-topology-updater -help
Usage of nfd-topology-updater:
  -add_dir_header
       If true, adds the file directory to the header of the log messages
  -alsologtostderr
       log to standard error as well as files
  -ca-file string
       Root certificate for verifying connections
  -cert-file string
       Certificate used for authenticating connections
  -key-file string
       Private key matching -cert-file
  -kubeconfig string
       Kube config file.
  -kubelet-config-file string
       Kubelet config file path. (default "/host-var/lib/kubelet/config.yaml")
  -log_backtrace_at value
       when logging hits line file:N, emit a stack trace
  -log_dir string
       If non-empty, write log files in this directory
  -log_file string
       If non-empty, use this log file
  -log_file_max_size uint
       Defines the maximum size a log file can grow to. Unit is megabytes. If the value is 0, the maximum file size is unlimited. (default 1800)
  -logtostderr
       log to standard error instead of files (default true)
  -no-publish
       Do not publish discovered features to the cluster-local Kubernetes API server.
  -one_output
       If true, only write logs to their native severity level (vs also writing to each lower severity level)
  -oneshot
       Update once and exit
  -podresources-socket string
       Pod Resource Socket path to use. (default "/host-var/lib/kubelet/pod-resources/kubelet.sock")
  -server string
       NFD server address to connecto to. (default "localhost:8080")
  -server-name-override string
       Hostname expected from server certificate, useful in testing
  -skip_headers
       If true, avoid header prefixes in the log messages
  -skip_log_headers
       If true, avoid headers when opening log files
  -sleep-interval duration
       Time to sleep between CR updates. Non-positive value implies no CR updatation (i.e. infinite sleep). [Default: 60s] (default 1m0s)
  -stderrthreshold value
       logs at or above this threshold go to stderr (default 2)
  -v value
       number for the log level verbosity
  -version
       Print version and exit.
  -vmodule value
       comma-separated list of pattern=N settings for file-filtered logging
  -watch-namespace string
       Namespace to watch pods (for testing/debugging purpose). Use * for all namespaces. (default "*")

NOTE:

NFD topology updater needs certain directories and/or files from the host mounted inside the NFD container. Thus, you need to provide Docker with the correct --volume options in order for them to work correctly when run stand-alone directly with docker run. See the template spec for up-to-date information about the required volume mounts.

PodResource API is a prerequisite for nfd-topology-updater. Preceding Kubernetes v1.23, the kubelet must be started with the following flag: --feature-gates=KubeletPodResourcesGetAllocatable=true. Starting Kubernetes v1.23, the GetAllocatableResources is enabled by default through KubeletPodResourcesGetAllocatable feature gate.

Documentation

All documentation resides under the docs directory in the source tree. It is designed to be served as a html site by GitHub Pages.

Building the documentation is containerized in order to fix the build environment. The recommended way for developing documentation is to run:

make site-serve

This will build the documentation in a container and serve it under localhost:4000/ making it easy to verify the results. Any changes made to the docs/ will automatically re-trigger a rebuild and are reflected in the served content and can be inspected with a simple browser refresh.

In order to just build the html documentation run:

make site-build

This will generate html documentation under docs/_site/.