[IS-618] - Add support for new node label schema

README.md

@@ -57,12 +57,12 @@ For example you could add the following flags to your Kubelet:
 ```
 
 ### Building
-If you wish to build the binary yourself; first make sure you have go installed and set up. Then clone this repo into your `$GOPATH` and download the dependencies using [`glide`](https://github.com/Masterminds/glide).
+If you wish to build the binary yourself; first make sure you have go installed and set up. Then clone this repo into your `$GOPATH` and download the dependencies using [`dep`](https://github.com/golang/dep).
 
 ```bash
 cd $GOPATH/src/github.com # Create this directory if it doesn't exist
 git clone git@github.com:pusher/k8s-spot-rescheduler pusher/k8s-spot-rescheduler
-glide install -v # Installs dependencies to vendor folder.
+dep ensure -v # Installs dependencies to vendor folder.
 ```
 
 Then build the code using `go build` which will produce the built binary in a file `k8s-spot-rescheduler`.

nodes/nodes.go

@@ -18,6 +18,7 @@ package nodes
 
 import (
 	"sort"
+	"strings"
 
 	apiv1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -27,9 +28,9 @@ import (
 
 var (
 	// OnDemandNodeLabel label for on-demand instances.
-	OnDemandNodeLabel = "node-role.kubernetes.io/worker"
+	OnDemandNodeLabel = "kubernetes.io/role=worker"
 	// SpotNodeLabel label for spot instances.
-	SpotNodeLabel = "node-role.kubernetes.io/spot-worker"
+	SpotNodeLabel = "kubernetes.io/role=spot-worker"
 	// OnDemand key for on-demand instances of NodesMap.
 	OnDemand NodeType
 	// Spot key for spot instances of NodesMap.
@@ -157,14 +158,46 @@ func getPodCPURequests(pod *apiv1.Pod) int64 {
 
 // Determines if a node has the spotNodeLabel assigned
 func isSpotNode(node *apiv1.Node) bool {
-	_, found := node.ObjectMeta.Labels[SpotNodeLabel]
-	return found
+	splitLabel := strings.SplitN(SpotNodeLabel, "=", 2)
+
+	// If "=" found, check for new label schema. If no "=" is found, check for
+	// old label schema
+	switch len(splitLabel) {
+	case 1:
+		_, found := node.ObjectMeta.Labels[SpotNodeLabel]
+		return found
+	case 2:
+		spotLabelKey := splitLabel[0]
+		spotLabelVal := splitLabel[1]
+
+		val, _ := node.ObjectMeta.Labels[spotLabelKey]
+		if val == spotLabelVal {
+			return true
+		}
+	}
+	return false
 }
 
 // Determines if a node has the OnDemandNodeLabel assigned
 func isOnDemandNode(node *apiv1.Node) bool {
-	_, found := node.ObjectMeta.Labels[OnDemandNodeLabel]
-	return found
+	splitLabel := strings.SplitN(OnDemandNodeLabel, "=", 2)
+
+	// If "=" found, check for new label schema. If no "=" is found, check for
+	// old label schema
+	switch len(splitLabel) {
+	case 1:
+		_, found := node.ObjectMeta.Labels[OnDemandNodeLabel]
+		return found
+	case 2:
+		onDemandLabelKey := splitLabel[0]
+		onDemandLabelVal := splitLabel[1]
+
+		val, _ := node.ObjectMeta.Labels[onDemandLabelKey]
+		if val == onDemandLabelVal {
+			return true
+		}
+	}
+	return false
 }
 
 // CopyNodeInfos returns an array of copies of the NodeInfos in this array.

nodes/nodes_test.go

@@ -29,12 +29,41 @@ import (
 	core "k8s.io/client-go/testing"
 )
 
+func TestIsSpotNode(t *testing.T) {
+	spotNode := createTestNodeWithLabel("fooSpotNode", 2000, map[string]string{"foo": "bar"})
+
+	SpotNodeLabel = "foo"
+	assert.True(t, isSpotNode(spotNode), "expected node with label 'foo' to be spot node")
+
+	SpotNodeLabel = "foo=bar"
+	assert.True(t, isSpotNode(spotNode), "expected node with label 'foo' and value 'bar' to be spot node")
+
+	SpotNodeLabel = "foo=baz"
+	assert.False(t, isSpotNode(spotNode), "expected node with label 'foo' and value 'bar' to not be spot node")
+}
+
+func TestIsOnDemandNode(t *testing.T) {
+	onDemandNode := createTestNodeWithLabel("fooDemandNode", 2000, map[string]string{"foo": "bar"})
+
+	OnDemandNodeLabel = "foo"
+	assert.True(t, isOnDemandNode(onDemandNode), "expected node with label 'foo' to be on demand node")
+
+	OnDemandNodeLabel = "foo=bar"
+	assert.True(t, isOnDemandNode(onDemandNode), "expected node with label 'foo' and value 'bar' to be on demand node")
+
+	OnDemandNodeLabel = "foo=baz"
+	assert.False(t, isOnDemandNode(onDemandNode), "expected node with label 'foo' and value 'bar' to not be on demand node")
+}
+
 func TestNewNodeMap(t *testing.T) {
+	OnDemandNodeLabel = "kubernetes.io/role=worker"
+	SpotNodeLabel = "kubernetes.io/role=spot-worker"
+
 	spotLabels := map[string]string{
-		SpotNodeLabel: "true",
+		"kubernetes.io/role": "spot-worker",
 	}
 	onDemandLabels := map[string]string{
-		OnDemandNodeLabel: "true",
+		"kubernetes.io/role": "worker",
 	}
 
 	nodes := []*apiv1.Node{

rescheduler.go

@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"net/http"
 	"os"
+	"strings"
 	"time"
 
 	"github.com/pusher/k8s-spot-rescheduler/metrics"
@@ -96,11 +97,11 @@ func main() {
 	// Add nodes labels as flags
 	flags.StringVar(&nodes.OnDemandNodeLabel,
 		"on-demand-node-label",
-		"node-role.kubernetes.io/worker",
+		"kubernetes.io/role=worker",
 		`Name of label on nodes to be considered for draining.`)
 	flags.StringVar(&nodes.SpotNodeLabel,
 		"spot-node-label",
-		"node-role.kubernetes.io/spot-worker",
+		"kubernetes.io/role=spot-worker",
 		`Name of label on nodes to be considered as targets for pods.`)
 
 	flags.Parse(os.Args)
@@ -110,6 +111,12 @@ func main() {
 		os.Exit(0)
 	}
 
+	err := validateArgs(nodes.OnDemandNodeLabel, nodes.SpotNodeLabel)
+	if err != nil {
+		fmt.Printf("Error: %s", err)
+		os.Exit(1)
+	}
+
 	glog.Infof("Running Rescheduler")
 
 	// Register metrics from metrics.go
@@ -419,3 +426,16 @@ func updateSpotNodeMetrics(spotNodeInfos nodes.NodeInfoArray, pdbs []*policyv1.P
 func podID(pod *apiv1.Pod) string {
 	return fmt.Sprintf("%s/%s", pod.Namespace, pod.Name)
 }
+
+// Checks that the node lablels provided as arguments are in fact, sane.
+func validateArgs(OnDemandNodeLabel string, SpotNodeLabel string) error {
+	if len(strings.Split(OnDemandNodeLabel, "=")) > 2 {
+		return fmt.Errorf("the on demand node label is not correctly formatted: expected '<label_name>' or '<label_name>=<label_value>', but got %s", OnDemandNodeLabel)
+	}
+
+	if len(strings.Split(SpotNodeLabel, "=")) > 2 {
+		return fmt.Errorf("the spot node label is not correctly formatted: expected '<label_name>' or '<label_name>=<label_value>', but got %s", SpotNodeLabel)
+	}
+
+	return nil
+}

rescheduler_test.go

@@ -70,6 +70,24 @@ func TestFindSpotNodeForPod(t *testing.T) {
 
 }
 
+func TestNodeLabelValidation(t *testing.T) {
+	onDemandLabel := "foo.bar/role=worker"
+	spotLabel := "foo.bar/node-role"
+
+	err := validateArgs(onDemandLabel, spotLabel)
+	assert.NoError(t, err)
+
+	onDemandLabel = "foo.bar/broken=worker=true"
+	err = validateArgs(onDemandLabel, spotLabel)
+	assert.EqualError(t, err, "the on demand node label is not correctly formatted: expected '<label_name>' or '<label_name>=<label_value>', but got foo.bar/broken=worker=true")
+
+	onDemandLabel = "foo.bar/role=worker"
+	spotLabel = "foo.bar/node-role=spot=fail"
+	err = validateArgs(onDemandLabel, spotLabel)
+	assert.EqualError(t, err, "the spot node label is not correctly formatted: expected '<label_name>' or '<label_name>=<label_value>', but got foo.bar/node-role=spot=fail")
+
+}
+
 func TestCanDrainNode(t *testing.T) {
 	predicateChecker := simulator.NewTestPredicateChecker()