22 KiB
Node feature discovery for Kubernetes
- Overview
- Command line interface
- Feature discovery
- Getting started
- Building from source
- Targeting nodes with specific features
- References
- License
- Demo
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>] [--config=<path>]
[--options=<config>]
node-feature-discovery -h | --help
node-feature-discovery --version
Options:
-h --help Show this screen.
--version Output version and exit.
--config=<path> Config file to use.
[Default: /etc/kubernetes/node-feature-discovery/node-feature-discovery.conf]
--options=<config> 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
will override settings read from the config file.
[Default: ]
--sources=<sources> Comma separated list of feature sources.
[Default: cpu,cpuid,iommu,kernel,local,memory,network,pci,pstate,rdt,storage,system]
--no-publish Do not publish discovered features to the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:
- CPU
- CPUID for x86/Arm64 CPU details
- IOMMU
- Kernel
- Local (user-specific features)
- Memory
- Network
- PCI
- Pstate (Intel P-State driver)
- RDT (Intel Resource Director Technology)
- Storage
- System
Feature labels
The published node labels encode a few pieces of information:
- Namespace, i.e.
feature.node.kubernetes.io - The source for each label (e.g.
cpuid). - The name of the discovered feature as it appears in the underlying
source, (e.g.
AESNIfrom cpuid). - The value of the discovered feature.
Feature label names adhere to the following pattern:
<namespace>/<source name>-<feature name>[.<attribute name>]
The last component (i.e. attribute-name) is optional, and only used if a
feature logically has sub-hierarchy, e.g. sriov.capable and
sriov.configure from the network source.
Note: only features that are available on a given node are labeled, so
the only label value published for features is the string "true".
{
"feature.node.kubernetes.io/cpu-<feature-name>": "true",
"feature.node.kubernetes.io/cpuid-<feature-name>": "true",
"feature.node.kubernetes.io/iommu-<feature-name>": "true",
"feature.node.kubernetes.io/kernel-<feature name>": "<feature value>",
"feature.node.kubernetes.io/memory-<feature-name>": "true",
"feature.node.kubernetes.io/network-<feature-name>": "true",
"feature.node.kubernetes.io/pci-<device label>.present": "true",
"feature.node.kubernetes.io/pstate-<feature-name>": "true",
"feature.node.kubernetes.io/rdt-<feature-name>": "true",
"feature.node.kubernetes.io/storage-<feature-name>": "true",
"feature.node.kubernetes.io/system-<feature name>": "<feature value>",
"feature.node.kubernetes.io/<hook name>-<feature name>": "<feature value>"
}
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.
CPU Features
The CPU feature source differs from the CPUID feature source in that it
discovers CPU related features that are actually enabled, whereas CPUID only
reports supported CPU capabilities (i.e. a capability might be supported but
not enabled) as reported by the cpuid instruction.
| Feature name | Description |
|---|---|
| hardware_multithreading | Hardware multithreading, such as Intel HTT, enabled (number of locical CPUs is greater than physical CPUs) |
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 |
Kernel Features
| Feature | Attribute | Description |
|---|---|---|
| config | <option name> | Kernel config option is enabled (set 'y' or 'm'). Default options are NO_HZ, NO_HZ_IDLE, NO_HZ_FULL and PREEMPT |
| selinux | enabled | Selinux is enabled on the node |
| version | full | Full kernel version as reported by /proc/sys/kernel/osrelease (e.g. '4.5.6-7-g123abcde') |
| major | First component of the kernel version (e.g. '4') | |
| minor | Second component of the kernel version (e.g. '5') | |
| revision | Third component of the kernel version (e.g. '6') |
Kernel config file to use, and, the set of config options to be detected are configurable. See configuration options for more information.
Local (User-specific Features)
NFD has a special feature source named local which is designed for running user-specific feature detector hooks. It provides a mechanism for users to implement custom feature sources in a pluggable way, without modifying nfd source code or Docker images. The local feature source can be used to advertise new user-specific features, and, for overriding labels created by the other feature sources.
The local feature source tries to execute files found under
/etc/kubernetes/node-feature-discovery/source.d/ directory. The hooks must be
available inside the Docker image so Volumes and VolumeMounts must be used if
standard NFD images are used.
The hook files must be executable. When executed, the hooks are supposed to
print all discovered features in stdout, one feature per line. Hooks can
advertise both binary and non-binary labels, using either <name> or
<name>=<value> output format.
Unlike the other feature sources, the name of the hook, instead of the name of
the feature source (that would be local in this case), is used as a prefix in
the label name, normally. However, if the <name> printed by the hook starts
with a slash (/) it is used as the label name as is, without any additional
prefix. This makes it possible for the hooks to fully control the feature
label names, e.g. for overriding labels created by other feature sources.
The value of the label is either true (for binary labels) or <value>
(for non-binary labels).
stderr output of the hooks is propagated to NFD log so it can be used for
debugging and logging.
An example:
User has a shell script
/etc/kubernetes/node-feature-discovery/source.d/my-source which has the
following stdout output:
MY_FEATURE_1
MY_FEATURE_2=myvalue
/override_source-OVERRIDE_BOOL
/override_source-OVERRIDE_VALUE=123
which, in turn, will translate into the following node labels:
feature.node.kubernetes.io/my-source-MY_FEATURE_1=true
feature.node.kubernetes.io/my-source-MY_FEATURE_2=myvalue
feature.node.kubernetes.io/override_source-OVERRIDE_BOOL=true
feature.node.kubernetes.io/override_source-OVERRIDE_VALUE=123
NFD tries to run any regular files found from the hooks directory. Any
additional data files your hook might need (e.g. a configuration file) should
be placed in a separate directory in order to avoid NFD unnecessarily trying to
execute these. You can use a subdirectory under the hooks directory, for
example /etc/kubernetes/node-feature-discovery/source.d/conf/.
NOTE! NFD will blindly run any executables placed/mounted in the hooks directory. It is the user's responsibility to review the hooks for e.g. possible security implications.
P-State Features
| Feature name | Description |
|---|---|
| turbo | Turbo frequencies are enabled in Intel pstate driver |
Memory Features
| Feature name | Description |
|---|---|
| numa | Multiple memory nodes i.e. NUMA architecture detected |
Network Features
| Feature | Attribute | Description |
|---|---|---|
| sriov | capable | Single Root Input/Output Virtualization (SR-IOV) enabled Network Interface Card(s) present |
| configured | SR-IOV virtual functions have been configured |
PCI Features
| Feature | Attribute | Description |
|---|---|---|
| <device label> | present | PCI device is detected |
<device label> is composed of raw PCI IDs, separated by underscores.
The set of fields used in <device label> is configurable, valid fields being
class, vendor, device, subsystem_vendor and subsystem_device.
Defaults are class and vendor. An example label using the default
label fields:
feature.node.kubernetes.io/pci-1200_8086.present=true
Also the set of PCI device classes that the feature source detects is configurable. By default, device classes (0x)03, (0x)0b40 and (0x)12, i.e. GPUs, co-processors and accelerator cards are detected.
See configuration options for more information on NFD config.
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 |
Storage Features
| Feature name | Description |
|---|---|
| nonrotationaldisk | Non-rotational disk, like SSD, is present in the node |
System Features
| Feature | Attribute | Description |
|---|---|---|
| os_release | ID | Operating system identifier |
| VERSION_ID | Operating system version identifier (e.g. '6.7') | |
| VERSION_ID.major | First component of the OS version id (e.g. '6') | |
| VERSION_ID.minor | Second component of the OS version id (e.g. '7') |
Getting started
System requirements
- Linux (x86_64/Arm64)
- [kubectl] kubectl-setup (properly set up and configured to work with your Kubernetes cluster)
- [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.yaml.template
When the NFD pods run, they contact the Kubernetes API server to add labels to the nodes 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.
Configuration options
NFD supports a configuration file. The default location is
/etc/kubernetes/node-feature-discovery/node-feature-discovery.conf, but,
this can be changed by specifying the--config command line flag. The file is
read inside the Docker image, and thus, Volumes and VolumeMounts are needed to
make your configuration available for NFD. The preferred method is to use a
ConfigMap.
For example, create a config map using the example config as a template:
cp node-feature-discovery.conf.example node-feature-discovery.conf
vim node-feature-discovery.conf # edit the configuration
kubectl create configmap node-feature-discovery-config --from-file=node-feature-discovery.conf
Then, configure Volumes and VolumeMounts in the Pod spec (just the relevant snippets shown below):
...
containers:
volumeMounts:
- name: node-feature-discovery-config
mountPath: "/etc/kubernetes/node-feature-discovery/"
...
volumes:
- name: node-feature-discovery-config
configMap:
name: node-feature-discovery-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.
Currently, the only available configuration options are related to the PCI and Kernel feature sources.
Building from source
Download the source code.
git clone https://github.com/kubernetes-sigs/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 image attribute in the file
node-feature-discovery-job.yaml.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:
feature.node.kubernetes.io/pstate-turbo: 'true'
For more details on targeting nodes, see node selection.
References
Github issues
Governance
This is a SIG-node subproject, hosted under the Kubernetes SIGs organization in Github. The project was established in 2016 as a Kubernetes Incubator project and migrated to Kubernetes SIGs in 2018.
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.