Node feature discovery for Kubernetes

• Overview
• Command line interface
• Feature discovery
  • Feature sources
  • Feature labels
• Getting started
  • System requirements
  • Usage
• Building from source
• Targeting nodes with specific features
• References
• License
• Demo

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Overview

This software enables node feature discovery for Kubernetes. It detects hardware features available on each node in a Kubernetes cluster, and advertises those features using node labels.

This project uses GitHub milestones for release planning.

Command line interface

To try out stand-alone, one can run a Docker container where node-feature-discovery is already set as entry point. Such run is useful for checking features-detection part, but labeling part is expected to fail. It is recommended to use --no-publish and --oneshot to achieve clean run in stand-alone case.

node-feature-discovery.

  Usage:
  node-feature-discovery [--no-publish] [--sources=<sources>] [--label-whitelist=<pattern>]
     [--oneshot | --sleep-interval=<seconds>]
  node-feature-discovery -h | --help
  node-feature-discovery --version

  Options:
  -h --help                   Show this screen.
  --version                   Output version and exit.
  --sources=<sources>         Comma separated list of feature sources.
                              [Default: cpuid,iommu,memory,network,pstate,rdt,selinux,storage]
  --no-publish                Do not publish discovered features to the
                              cluster-local Kubernetes API server.
  --label-whitelist=<pattern> Regular expression to filter label names to
                              publish to the Kubernetes API server. [Default: ]
  --oneshot                   Label once and exit.
  --sleep-interval=<seconds>  Time to sleep between re-labeling. Non-positive
                              value implies no re-labeling (i.e. infinite
                              sleep). [Default: 60s]

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 template spec for up-to-date information about the required volume mounts.

Feature discovery

Feature sources

The current set of feature sources are the following:

• CPUID for x86/Arm64 CPU details
• IOMMU
• Memory
• Network
• Pstate (Intel P-State driver)
• RDT (Intel Resource Director Technology)
• Selinux
• Storage

Feature labels

The published node labels encode a few pieces of information:

• A "namespace" (e.g. node.alpha.kubernetes-incubator.io/nfd).
• The version of this discovery code that wrote the label, according to git describe --tags --dirty --always.
• The source for each label (e.g. cpuid).
• The name of the discovered feature as it appears in the underlying source, (e.g. AESNI from cpuid).

Note: only features that are available on a given node are labeled, so the only label value published for features is the string "true".

{
  "node.alpha.kubernetes-incubator.io/node-feature-discovery.version": "v0.3.0",
  "node.alpha.kubernetes-incubator.io/nfd-cpuid-<feature-name>": "true",
  "node.alpha.kubernetes-incubator.io/nfd-iommu-<feature-name>": "true",
  "node.alpha.kubernetes-incubator.io/nfd-memory-<feature-name>": "true",
  "node.alpha.kubernetes-incubator.io/nfd-network-<feature-name>": "true",
  "node.alpha.kubernetes-incubator.io/nfd-pstate-<feature-name>": "true",
  "node.alpha.kubernetes-incubator.io/nfd-rdt-<feature-name>": "true",
  "node.alpha.kubernetes-incubator.io/nfd-selinux-<feature-name>": "true",
  "node.alpha.kubernetes-incubator.io/nfd-storage-<feature-name>": "true"
}

The --sources flag controls which sources to use for discovery.

Note: Consecutive runs of node-feature-discovery will update the labels on a given node. If features are not discovered on a consecutive run, the corresponding label will be removed. This includes any restrictions placed on the consecutive run, such as restricting discovered features with the --label-whitelist option.

X86 CPUID Features (Partial List)

Feature name	Description
ADX	Multi-Precision Add-Carry Instruction Extensions (ADX)
AESNI	Advanced Encryption Standard (AES) New Instructions (AES-NI)
AVX	Advanced Vector Extensions (AVX)
AVX2	Advanced Vector Extensions 2 (AVX2)
BMI1	Bit Manipulation Instruction Set 1 (BMI)
BMI2	Bit Manipulation Instruction Set 2 (BMI2)
SSE4.1	Streaming SIMD Extensions 4.1 (SSE4.1)
SSE4.2	Streaming SIMD Extensions 4.2 (SSE4.2)
SGX	Software Guard Extensions (SGX)

Arm64 CPUID Features (Partial List)

Feature name	Description
AES	Announcing the Advanced Encryption Standard
EVSTRM	Event Stream Frequency Features
FPHP	Half Precision(16bit) Floating Point Data Processing Instructions
ASIMDHP	Half Precision(16bit) Asimd Data Processing Instructions
ATOMICS	Atomic Instructions to the A64
ASIMRDM	Support for Rounding Double Multiply Add/Subtract
PMULL	Optional Cryptographic and CRC32 Instructions
JSCVT	Perform Conversion to Match Javascript
DCPOP	Persistent Memory Support

IOMMU Features

Feature name	Description
enabled	IOMMU is present and enabled in the kernel

Memory Features

Feature name	Description
numa	Multiple memory nodes i.e. NUMA architecture detected

Network Features

Feature name	Description
SRIOV	Single Root Input/Output Virtualization (SR-IOV) enabled Network Interface Card

RDT (Intel Resource Director Technology) Features

Feature name	Description
RDTMON	Intel RDT Monitoring Technology
RDTCMT	Intel Cache Monitoring (CMT)
RDTMBM	Intel Memory Bandwidth Monitoring (MBM)
RDTL3CA	Intel L3 Cache Allocation Technology
RDTL2CA	Intel L2 Cache Allocation Technology
RDTMBA	Intel Memory Bandwidth Allocation (MBA) Technology

Selinux Features

Feature name	Description
selinux	selinux is enabled on the node

Storage Features

Feature name	Description
nonrotationaldisk	Non-rotational disk, like SSD, is present in the node

Getting started

System requirements

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

Usage

Feature discovery is preferably run as a Kubernetes DaemonSet. There is an example spec that can be used as a template, or, as is when just trying out the service:

kubectl create -f rbac.yaml
kubectl create -f node-feature-discovery-daemonset.json.template

When the job runs, it contacts the Kubernetes API server to add labels to the node to advertise hardware features.

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 templates will configure these for you.

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.

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

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.

Building from source

Download the source code.

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

Build the container image:

cd <project-root>
make

NOTE: Our default docker image is hosted in quay.io. To override the QUAY_REGISTRY_USER use the -e option as follows: QUAY_REGISTRY_USER=<my-username> make image -e

You can also specify a build tool different from Docker, for example:

make IMAGE_BUILD_CMD="buildah bud"

Push the container image (optional, this example with Docker)

docker push <quay-domain-name>/<registry-user>/<image-name>:<version>

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

To use your published image from the step above instead of the quay.io/kubernetes_incubator/node-feature-discovery image, edit line 40 in the file node-feature-discovery-job.json.template to the new location (<quay-domain-name>/<registry-user>/<image-name>[:<version>]).

Targeting Nodes with Specific Features

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": {
                "node.alpha.kubernetes-incubator.io/nfd-pstate-turbo": "true"
        }
    }
}

For more details on targeting nodes, see node selection.

References

Github issues

• #28310
• #28311
• #28312

Design proposal

Kubernetes Incubator

This is a Kubernetes Incubator project. The project was established 2016-08-29. The incubator team for the project is:

• Sponsor: Dawn Chen (@dchen1107)
• Champion: David Oppenheimer (@davidopp)
• SIG: sig-node

License

This is open source software released under the Apache 2.0 License.

Demo

A demo on the benefits of using node feature discovery can be found in demo.