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Add a flag to exclude tainted nodes
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On a cluster that has many tainted nodes it's not straightforward to understand
whether there is sufficient capacity to drain one: nodes with taints can make
it seem like there is more capacity than there really would be.

This patch solves for the simplest use case by allowing all tainted nodes to be
excluded with a flag.
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@barrykp @robscott
barrykp authored and robscott committed Jan 4, 2024
1 parent ef7cc2b commit a68c7d4
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Showing 4 changed files with 51 additions and 15 deletions.
15 changes: 12 additions & 3 deletions pkg/capacity/capacity.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,14 +29,14 @@ import (
)

// FetchAndPrint gathers cluster resource data and outputs it
func FetchAndPrint(showContainers, showPods, showUtil, showPodCount, availableFormat bool, podLabels, nodeLabels, namespaceLabels, namespace, kubeContext, kubeConfig, output, sortBy string) {
func FetchAndPrint(showContainers, showPods, showUtil, showPodCount, excludeTainted, availableFormat bool, podLabels, nodeLabels, namespaceLabels, namespace, kubeContext, kubeConfig, output, sortBy string) {
clientset, err := kube.NewClientSet(kubeContext, kubeConfig)
if err != nil {
fmt.Printf("Error connecting to Kubernetes: %v\n", err)
os.Exit(1)
}

podList, nodeList := getPodsAndNodes(clientset, podLabels, nodeLabels, namespaceLabels, namespace)
podList, nodeList := getPodsAndNodes(clientset, excludeTainted, podLabels, nodeLabels, namespaceLabels, namespace)
var pmList *v1beta1.PodMetricsList
var nmList *v1beta1.NodeMetricsList

Expand All @@ -59,14 +59,23 @@ func FetchAndPrint(showContainers, showPods, showUtil, showPodCount, availableFo
printList(&cm, showContainers, showPods, showUtil, showPodCount, showNamespace, output, sortBy, availableFormat)
}

func getPodsAndNodes(clientset kubernetes.Interface, podLabels, nodeLabels, namespaceLabels, namespace string) (*corev1.PodList, *corev1.NodeList) {
func getPodsAndNodes(clientset kubernetes.Interface, excludeTainted bool, podLabels, nodeLabels, namespaceLabels, namespace string) (*corev1.PodList, *corev1.NodeList) {
nodeList, err := clientset.CoreV1().Nodes().List(context.TODO(), metav1.ListOptions{
LabelSelector: nodeLabels,
})
if err != nil {
fmt.Printf("Error listing Nodes: %v\n", err)
os.Exit(2)
}
if excludeTainted {
filteredNodeList := []corev1.Node{}
for _, node := range nodeList.Items {
if len(node.Spec.Taints) == 0 {
filteredNodeList = append(filteredNodeList, node)
}
}
nodeList.Items = filteredNodeList
}

podList, err := clientset.CoreV1().Pods(namespace).List(context.TODO(), metav1.ListOptions{
LabelSelector: podLabels,
Expand Down
41 changes: 31 additions & 10 deletions pkg/capacity/capacity_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,8 +25,8 @@ import (

func TestGetPodsAndNodes(t *testing.T) {
clientset := fake.NewSimpleClientset(
node("mynode", map[string]string{"hello": "world"}),
node("mynode2", map[string]string{"hello": "world", "moon": "lol"}),
node("mynode", map[string]string{"hello": "world"}, false),
node("mynode2", map[string]string{"hello": "world", "moon": "lol"}, true),
namespace("default", map[string]string{"app": "true"}),
namespace("kube-system", map[string]string{"system": "true"}),
namespace("other", map[string]string{"app": "true", "system": "true"}),
Expand All @@ -40,7 +40,7 @@ func TestGetPodsAndNodes(t *testing.T) {
pod("mynode", "default", "mypod6", map[string]string{"g": "test"}),
)

podList, nodeList := getPodsAndNodes(clientset, "", "", "", "")
podList, nodeList := getPodsAndNodes(clientset, false, "", "", "", "")
assert.Equal(t, []string{"mynode", "mynode2"}, listNodes(nodeList))
assert.Equal(t, []string{
"another/mypod5",
Expand All @@ -52,7 +52,16 @@ func TestGetPodsAndNodes(t *testing.T) {
"other/mypod3",
}, listPods(podList))

podList, nodeList = getPodsAndNodes(clientset, "", "hello=world", "", "")
podList, nodeList = getPodsAndNodes(clientset, true, "", "hello=world", "", "")
assert.Equal(t, []string{"mynode"}, listNodes(nodeList))
assert.Equal(t, []string{
"another/mypod5",
"default/mypod",
"default/mypod6",
"other/mypod2",
}, listPods(podList))

podList, nodeList = getPodsAndNodes(clientset, false, "", "hello=world", "", "")
assert.Equal(t, []string{"mynode", "mynode2"}, listNodes(nodeList))
assert.Equal(t, []string{
"another/mypod5",
Expand All @@ -64,35 +73,35 @@ func TestGetPodsAndNodes(t *testing.T) {
"other/mypod3",
}, listPods(podList))

podList, nodeList = getPodsAndNodes(clientset, "", "moon=lol", "", "")
podList, nodeList = getPodsAndNodes(clientset, false, "", "moon=lol", "", "")
assert.Equal(t, []string{"mynode2"}, listNodes(nodeList))
assert.Equal(t, []string{
"default/mypod4",
"kube-system/mypod1",
"other/mypod3",
}, listPods(podList))

podList, nodeList = getPodsAndNodes(clientset, "a=test", "", "", "")
podList, nodeList = getPodsAndNodes(clientset, false, "a=test", "", "", "")
assert.Equal(t, []string{"mynode", "mynode2"}, listNodes(nodeList))
assert.Equal(t, []string{
"default/mypod",
}, listPods(podList))

podList, nodeList = getPodsAndNodes(clientset, "a=test,b!=test", "", "app=true", "")
podList, nodeList = getPodsAndNodes(clientset, false, "a=test,b!=test", "", "app=true", "")
assert.Equal(t, []string{"mynode", "mynode2"}, listNodes(nodeList))
assert.Equal(t, []string{
"default/mypod",
}, listPods(podList))

podList, nodeList = getPodsAndNodes(clientset, "a=test,b!=test", "", "", "default")
podList, nodeList = getPodsAndNodes(clientset, false, "a=test,b!=test", "", "", "default")
assert.Equal(t, []string{"mynode", "mynode2"}, listNodes(nodeList))
assert.Equal(t, []string{
"default/mypod",
}, listPods(podList))
}

func node(name string, labels map[string]string) *corev1.Node {
return &corev1.Node{
func node(name string, labels map[string]string, tainted bool) *corev1.Node {
n := &corev1.Node{
TypeMeta: metav1.TypeMeta{
Kind: "Node",
APIVersion: "v1",
Expand All @@ -102,6 +111,18 @@ func node(name string, labels map[string]string) *corev1.Node {
Labels: labels,
},
}
if tainted {
n.Spec = corev1.NodeSpec{
Taints: []corev1.Taint{
{
Key: "taint",
Value: "true",
Effect: corev1.TaintEffectNoSchedule,
},
},
}
}
return n
}

func namespace(name string, labels map[string]string) *corev1.Namespace {
Expand Down
3 changes: 3 additions & 0 deletions pkg/capacity/resources.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -129,6 +129,9 @@ func buildClusterMetric(podList *corev1.PodList, pmList *v1beta1.PodMetricsList,

if nmList != nil {
for _, nm := range nmList.Items {
if cm.nodeMetrics[nm.Name] == nil {
continue
}
cm.nodeMetrics[nm.Name].cpu.utilization = nm.Usage["cpu"]
cm.nodeMetrics[nm.Name].memory.utilization = nm.Usage["memory"]
}
Expand Down
7 changes: 5 additions & 2 deletions pkg/cmd/root.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,7 @@ var showUtil bool
var showPodCount bool
var podLabels string
var nodeLabels string
var excludeTainted bool
var namespaceLabels string
var namespace string
var kubeContext string
Expand All @@ -50,8 +51,8 @@ var rootCmd = &cobra.Command{
os.Exit(1)
}

capacity.FetchAndPrint(showContainers, showPods, showUtil, showPodCount, availableFormat, podLabels, nodeLabels,
namespaceLabels, namespace, kubeContext, kubeConfig, outputFormat, sortBy)
capacity.FetchAndPrint(showContainers, showPods, showUtil, showPodCount, excludeTainted, availableFormat, podLabels,
nodeLabels, namespaceLabels, namespace, kubeContext, kubeConfig, outputFormat, sortBy)
},
}

Expand All @@ -70,6 +71,8 @@ func init() {
"pod-labels", "l", "", "labels to filter pods with")
rootCmd.PersistentFlags().StringVarP(&nodeLabels,
"node-labels", "", "", "labels to filter nodes with")
rootCmd.PersistentFlags().BoolVarP(&excludeTainted,
"no-taint", "", false, "exclude nodes with taints")
rootCmd.PersistentFlags().StringVarP(&namespaceLabels,
"namespace-labels", "", "", "labels to filter namespaces with")
rootCmd.PersistentFlags().StringVarP(&namespace,
Expand Down

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