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node-feature-discovery/source/memory/memory.go
Markus Lehtonen 852cf4b61d source: introduce FeatureSource interface
Specify a new interface for managing "raw" feature data. This is the
first step to separate raw feature data from node labels. None of the
feature sources implement this interface, yet.

This patch unifies the data format of "raw" features by dividing them
into three different basic types.
- keys, a set of names without any associated values, e.g. CPUID flags
  or loaded kernel modules
- values, a map of key-value pairs, for features with a single value,
  e.g. kernel config flags or os version
- instances, a list of instances each of which has multiple attributes
  (key-value pairs of their own), e.g. PCI or USB devices

The new feature data types are defined in a new "pkg/api/feature"
package, catering decoupling and re-usability of code e.g. within future
extentions of the NFD gRPC API.

Rename the Discover() method of LabelSource interface to GetLabels().
2021-09-20 09:58:07 +03:00

124 lines
2.9 KiB
Go

/*
Copyright 2018-2021 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package memory
import (
"io/ioutil"
"os"
"strings"
"k8s.io/klog/v2"
"sigs.k8s.io/node-feature-discovery/source"
)
const Name = "memory"
// memorySource implements the LabelSource interface.
type memorySource struct{}
// Singleton source instance
var (
src memorySource
_ source.LabelSource = &src
)
// Name returns an identifier string for this feature source.
func (s *memorySource) Name() string { return Name }
// Priority method of the LabelSource interface
func (s *memorySource) Priority() int { return 0 }
// GetLabels method of the LabelSource interface
func (s *memorySource) GetLabels() (source.FeatureLabels, error) {
features := source.FeatureLabels{}
// Detect NUMA
numa, err := isNuma()
if err != nil {
klog.Errorf("failed to detect NUMA topology: %s", err)
} else if numa {
features["numa"] = true
}
// Detect NVDIMM
nv, err := detectNvdimm()
if err != nil {
klog.Errorf("NVDIMM detection failed: %s", err)
} else {
for k, v := range nv {
features["nv."+k] = v
}
}
return features, nil
}
// Detect if the platform has NUMA topology
func isNuma() (bool, error) {
// Find out how many nodes are online
// Multiple nodes is a sign of NUMA
bytes, err := ioutil.ReadFile(source.SysfsDir.Path("devices/system/node/online"))
if err != nil {
return false, err
}
// File content is expected to be:
// "0\n" in one-node case
// "0-K\n" in N-node case where K=N-1
// presence of newline requires TrimSpace
if strings.TrimSpace(string(bytes)) != "0" {
// more than one node means NUMA
return true, nil
}
return false, nil
}
// Detect NVDIMM devices and configuration
func detectNvdimm() (map[string]bool, error) {
features := make(map[string]bool)
// Check presence of physical devices
devices, err := ioutil.ReadDir(source.SysfsDir.Path("class/nd"))
if err == nil {
if len(devices) > 0 {
features["present"] = true
}
} else if os.IsNotExist(err) {
return nil, nil
} else {
return nil, err
}
// Check presence of DAX-configured regions
devices, err = ioutil.ReadDir(source.SysfsDir.Path("bus/nd/devices"))
if err == nil {
for _, d := range devices {
if strings.HasPrefix(d.Name(), "dax") {
features["dax"] = true
}
}
} else {
klog.Warningf("failed to detect NVDIMM configuration: %s", err)
}
return features, nil
}
func init() {
source.Register(&src)
}