Allow optionally setting node taints defined on the NodeFeatureRule CR

cmd/nfd-master/main.go

@@ -96,6 +96,8 @@ func initFlags(flagset *flag.FlagSet) *master.Args {
 			"NB: the label namespace is omitted i.e. the filter is only applied to the name part after '/'.")
 	flagset.BoolVar(&args.NoPublish, "no-publish", false,
 		"Do not publish feature labels")
+	flagset.BoolVar(&args.EnableTaints, "enable-taints", false,
+		"Enable node tainting feature")
 	flagset.BoolVar(&args.FeatureRulesController, "featurerules-controller", true,
 		"Enable controller for NodeFeatureRule objects. Generates node labels based on the rules in these CRs.")
 	flagset.IntVar(&args.Port, "port", 8080,

deployment/base/nfd-crds/cr-sample.yaml

@@ -7,6 +7,12 @@ spec:
     # The following feature demonstrates the capabilities of the matchFeatures and
     # matchAny matchers.
     - name: "my feature rule"
+      taints:
+        - effect: PreferNoSchedule
+          key: "feature.node.kubernetes.io/special-node"
+          value: "true"
+        - effect: NoExecute
+          key: "feature.node.kubernetes.io/dedicated-node"
       labels:
         "my-complex-feature": "my-value"
       # matchFeatures implements a logical AND over feature matchers.

deployment/base/nfd-crds/nodefeaturerule-crd.yaml

@@ -189,6 +189,35 @@ spec:
                     name:
                       description: Name of the rule.
                       type: string
+                    taints:
+                      description: Taints to create if the rule matches.
+                      items:
+                        description: The node this Taint is attached to has the "effect"
+                          on any pod that does not tolerate the Taint.
+                        properties:
+                          effect:
+                            description: Required. The effect of the taint on pods
+                              that do not tolerate the taint. Valid effects are NoSchedule,
+                              PreferNoSchedule and NoExecute.
+                            type: string
+                          key:
+                            description: Required. The taint key to be applied to
+                              a node.
+                            type: string
+                          timeAdded:
+                            description: TimeAdded represents the time at which the
+                              taint was added. It is only written for NoExecute taints.
+                            format: date-time
+                            type: string
+                          value:
+                            description: The taint value corresponding to the taint
+                              key.
+                            type: string
+                        required:
+                        - effect
+                        - key
+                        type: object
+                      type: array
                     vars:
                       additionalProperties:
                         type: string

deployment/helm/node-feature-discovery/crds/nodefeaturerule-crd.yaml

@@ -189,6 +189,35 @@ spec:
                     name:
                       description: Name of the rule.
                       type: string
+                    taints:
+                      description: Taints to create if the rule matches.
+                      items:
+                        description: The node this Taint is attached to has the "effect"
+                          on any pod that does not tolerate the Taint.
+                        properties:
+                          effect:
+                            description: Required. The effect of the taint on pods
+                              that do not tolerate the taint. Valid effects are NoSchedule,
+                              PreferNoSchedule and NoExecute.
+                            type: string
+                          key:
+                            description: Required. The taint key to be applied to
+                              a node.
+                            type: string
+                          timeAdded:
+                            description: TimeAdded represents the time at which the
+                              taint was added. It is only written for NoExecute taints.
+                            format: date-time
+                            type: string
+                          value:
+                            description: The taint value corresponding to the taint
+                              key.
+                            type: string
+                        required:
+                        - effect
+                        - key
+                        type: object
+                      type: array
                     vars:
                       additionalProperties:
                         type: string

docs/reference/master-commandline-reference.md

@@ -99,6 +99,18 @@ Example:
 nfd-master -cert-file=/opt/nfd/master.crt -key-file=/opt/nfd/master.key -ca-file=/opt/nfd/ca.crt
 ```
 
+### -enable-taints
+
+The `-enable-taints` flag enables/disables node tainting feature of NFD.
+
+Default: *false*
+
+Example:
+
+```bash
+nfd-master -enable-taints=true
+```
+
 ### -key-file
 
 The `-key-file` is one of the three flags (together with `-ca-file` and

docs/usage/customization-guide.md

@@ -30,8 +30,8 @@ labeling:
 ## NodeFeatureRule custom resource
 
 `NodeFeatureRule` objects provide an easy way to create vendor or application
-specific labels. It uses a flexible rule-based mechanism for creating labels
-based on node feature.
+specific labels and taints. It uses a flexible rule-based mechanism for creating
+labels and optionally taints based on node features.
 
 ### A NodeFeatureRule example
 
@@ -76,6 +76,54 @@ re-labeling delay up to the sleep-interval of nfd-worker (1 minute by default).
 
 See [Label rule format](#label-rule-format) for detailed description of
 available fields and how to write labeling rules.
+### NodeFeatureRule tainting feature
+
+This feature is experimental.
+
+In some circumstances it is desirable keep nodes with specialized hardware away from
+running general workload and instead leave them for workloads that need the specialized
+hardware. One way to achieve it is to taint the nodes with the specialized hardware
+and add corresponding toleration to pods that require the special hardware. NFD
+offers node tainting functionality which is disabled by default. User can define
+one or more custom taints via the `taints` field of the NodeFeatureRule CR. The
+same rule-based mechanism is applied here and the NFD taints only rule matching nodes.
+
+To enable the tainting feature, `--enable-taints` flag needs to be set to `true`.
+If the flag `--enable-taints` is set to `false` (i.e. disabled), taints defined in
+the NodeFeatureRule CR have no effect and will be ignored by the NFD master.
+
+**NOTE**: Before enabling any taints, make sure to edit nfd-worker daemonset to
+tolerate the taints to be created. Otherwise, already running pods that do not
+tolerate the taint are evicted immediately from the node including the nfd-worker
+pod.
+
+Example NodeFeatureRule with custom taints:
+
+```yaml
+apiVersion: nfd.k8s-sigs.io/v1alpha1
+kind: NodeFeatureRule
+metadata:
+  name: my-sample-rule-object
+spec:
+  rules:
+    - name: "my sample taint rule"
+      taints:
+        - effect: PreferNoSchedule
+          key: "feature.node.kubernetes.io/special-node"
+          value: "true"
+        - effect: NoExecute
+          key: "feature.node.kubernetes.io/dedicated-node"
+      matchFeatures:
+        - feature: kernel.loadedmodule
+          matchExpressions:
+            dummy: {op: Exists}
+        - feature: kernel.config
+          matchExpressions:
+            X86: {op: In, value: ["y"]}
+```
+
+In this example, if the `my sample taint rule` rule is matched, `feature.node.kubernetes.io/pci-0300_1d0f.present=true:NoExecute`
+and `feature.node.kubernetes.io/cpu-cpuid.ADX:NoExecute` taints are set on the node.
 
 ### NodeFeatureRule controller
 
@@ -365,6 +413,15 @@ details.
 labels specified in the `labels` field will override anything
 originating from `labelsTemplate`.
 
+### Taints
+
+*taints* is a list of taint entries and each entry can have `key`, `value` and `effect`,
+where the `value` is optional. Effect could be `NoSchedule`, `PreferNoSchedule`
+or `NoExecute`. To learn more about the meaning of these effects, check out k8s [documentation](https://kubernetes.io/docs/concepts/scheduling-eviction/taint-and-toleration/).
+
+**NOTE** taints field is not available for the custom rules of nfd-worker and only
+for NodeFeatureRule objects.
+
 #### Vars
 
 The `.vars` field is a map of values (key-value pairs) to store for subsequent

pkg/apis/nfd/v1alpha1/annotations_labels.go

@@ -43,4 +43,7 @@ const (
 
 	// WorkerVersionAnnotation is the annotation that holds the version of nfd-worker running on the node
 	WorkerVersionAnnotation = AnnotationNs + "/worker.version"
+
+	// NodeTaintsAnnotation is the annotation that holds the taints that nfd-master set on the node
+	NodeTaintsAnnotation = AnnotationNs + "/taints"
 )

pkg/apis/nfd/v1alpha1/rule.go

@@ -22,8 +22,8 @@ import (
 	"strings"
 	"text/template"
 
+	corev1 "k8s.io/api/core/v1"
 	"k8s.io/klog/v2"
-
 	"sigs.k8s.io/node-feature-discovery/pkg/utils"
 )
 
@@ -32,6 +32,7 @@ import (
 type RuleOutput struct {
 	Labels map[string]string
 	Vars   map[string]string
+	Taints []corev1.Taint
 }
 
 // Execute the rule against a set of input features.
@@ -94,9 +95,8 @@ func (r *Rule) Execute(features *Features) (RuleOutput, error) {
 		vars[k] = v
 	}
 
-	ret := RuleOutput{Labels: labels, Vars: vars}
+	ret := RuleOutput{Labels: labels, Vars: vars, Taints: r.Taints}
 	utils.KlogDump(2, fmt.Sprintf("rule %q matched with: ", r.Name), "  ", ret)
-
 	return ret, nil
 }
 

pkg/apis/nfd/v1alpha1/types.go

@@ -17,6 +17,7 @@ limitations under the License.
 package v1alpha1
 
 import (
+	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
@@ -120,6 +121,10 @@ type Rule struct {
 	// +optional
 	VarsTemplate string `json:"varsTemplate"`
 
+	// Taints to create if the rule matches.
+	// +optional
+	Taints []corev1.Taint `json:"taints,omitempty"`
+
 	// MatchFeatures specifies a set of matcher terms all of which must match.
 	// +optional
 	MatchFeatures FeatureMatcher `json:"matchFeatures"`