[#495] implement feature request: topologySpreadConstraints

score/podtopologyspreadconstraints/podtopologyspreadconstraints.go

@@ -0,0 +1,57 @@
+package podtopologyconstraints
+
+import (
+	ks "github.com/zegl/kube-score/domain"
+	"github.com/zegl/kube-score/score/checks"
+	"github.com/zegl/kube-score/scorecard"
+)
+
+func Register(allChecks *checks.Checks) {
+	allChecks.RegisterPodCheck("Pod Topology Spread Constraints", "Pod Topology Spread Constraints", podTopologySpreadConstraints)
+}
+
+func podTopologySpreadConstraints(pod ks.PodSpecer) (score scorecard.TestScore, err error) {
+	spreads := pod.GetPodTemplateSpec().Spec.TopologySpreadConstraints
+
+	if spreads == nil {
+		score.Grade = scorecard.GradeAllOK
+		score.AddComment("", "Pod Topology Spread Constraints", "No Pod Topology Spread Constraints set, kube-scheduler defaults assumed")
+		return
+	}
+
+	for _, spread := range spreads {
+		if spread.LabelSelector == nil {
+			score.Grade = scorecard.GradeCritical
+			score.AddComment("", "Pod Topology Spread Constraints", "No labelSelector detected. A label selector is needed determine the number of pods in a topology domain")
+			return
+		}
+
+		if spread.MaxSkew == 0 {
+			score.Grade = scorecard.GradeCritical
+			score.AddComment("", "Pod Topology Spread Constraints", "MaxSkew is set to zero. This is not allowed.")
+			return
+		}
+
+		if spread.MinDomains != nil && *spread.MinDomains == 0 {
+			score.Grade = scorecard.GradeCritical
+			score.AddComment("", "Pod Topology Spread Constraints", "MaxDomain set to zero. This is not allowed. Constraint behaves if minDomains is set to 1 if nil")
+			return
+		}
+
+		if spread.TopologyKey == "" {
+			score.Grade = scorecard.GradeCritical
+			score.AddComment("", "Pod Topology Spread Constraints", "TopologyKey is not set. This is the key of node labels used to bucket nodes into a domain")
+			return
+		}
+
+		if spread.WhenUnsatisfiable != "DoNotSchedule" && spread.WhenUnsatisfiable != "ScheduleAnyway" {
+			score.Grade = scorecard.GradeCritical
+			score.AddComment("", "Pod Topology Spread Constraints", "Invalid WhenUnsatisfiable setting detected")
+			return
+		}
+	}
+
+	score.Grade = scorecard.GradeAllOK
+	score.AddComment("", "Pod Topology Spread Constraints", "Pod Topology Spread Constraints")
+	return
+}

score/podtopologyspreadconstraints_test.go

@@ -0,0 +1,42 @@
+package score
+
+import (
+	"testing"
+
+	"github.com/zegl/kube-score/scorecard"
+)
+
+func TestPodTopologySpreadContraintsWithOneConstraint(t *testing.T) {
+	t.Parallel()
+	testExpectedScore(t, "pod-topology-spread-constraints-one-constraint.yaml", "Pod Topology Spread Constraints", scorecard.GradeAllOK)
+}
+
+func TestPodTopologySpreadContraintsWithTwoConstraints(t *testing.T) {
+	t.Parallel()
+	testExpectedScore(t, "pod-topology-spread-constraints-two-constraints.yaml", "Pod Topology Spread Constraints", scorecard.GradeAllOK)
+}
+
+func TestPodTopologySpreadContraintsNoLabelSelector(t *testing.T) {
+	t.Parallel()
+	testExpectedScore(t, "pod-topology-spread-constraints-no-labelselector.yaml", "Pod Topology Spread Constraints", scorecard.GradeCritical)
+}
+
+func TestPodTopologySpreadContraintsInvalidMaxSkew(t *testing.T) {
+	t.Parallel()
+	testExpectedScore(t, "pod-topology-spread-constraints-invalid-maxskew.yaml", "Pod Topology Spread Constraints", scorecard.GradeCritical)
+}
+
+func TestPodTopologySpreadContraintsInvalidMinDomains(t *testing.T) {
+	t.Parallel()
+	testExpectedScore(t, "pod-topology-spread-constraints-invalid-mindomains.yaml", "Pod Topology Spread Constraints", scorecard.GradeCritical)
+}
+
+func TestPodTopologySpreadContraintsNoTopologyKey(t *testing.T) {
+	t.Parallel()
+	testExpectedScore(t, "pod-topology-spread-constraints-no-topologykey.yaml", "Pod Topology Spread Constraints", scorecard.GradeCritical)
+}
+
+func TestPodTopologySpreadContraintsInvalidDirective(t *testing.T) {
+	t.Parallel()
+	testExpectedScore(t, "pod-topology-spread-constraints-invalid-whenunsatisfiable.yaml", "Pod Topology Spread Constraints", scorecard.GradeCritical)
+}

score/testdata/pod-topology-spread-constraints-invalid-maxskew.yaml

@@ -0,0 +1,17 @@
+kind: Pod
+apiVersion: v1
+metadata:
+  name: mypod
+  labels:
+    foo: bar
+spec:
+  topologySpreadConstraints:
+  - maxSkew: 0
+    topologyKey: zone
+    whenUnsatisfiable: DoNotSchedule
+    labelSelector:
+      matchLabels:
+        foo: bar
+  containers:
+    - name: pause
+      image: registry.k8s.io/pause:3.1

score/testdata/pod-topology-spread-constraints-invalid-mindomains.yaml

@@ -0,0 +1,18 @@
+kind: Pod
+apiVersion: v1
+metadata:
+  name: mypod
+  labels:
+    foo: bar
+spec:
+  topologySpreadConstraints:
+  - maxSkew: 1
+    minDomains: 0
+    topologyKey: zone
+    whenUnsatisfiable: DoNotSchedule
+    labelSelector:
+      matchLabels:
+        foo: bar
+  containers:
+    - name: pause
+      image: registry.k8s.io/pause:3.1

score/testdata/pod-topology-spread-constraints-invalid-whenunsatisfiable.yaml

@@ -0,0 +1,17 @@
+kind: Pod
+apiVersion: v1
+metadata:
+  name: mypod
+  labels:
+    foo: bar
+spec:
+  topologySpreadConstraints:
+  - maxSkew: 1
+    topologyKey: zone
+    whenUnsatisfiable: DoNotSCHEDULE 
+    labelSelector:
+      matchLabels:
+        foo: bar
+  containers:
+    - name: pause
+      image: registry.k8s.io/pause:3.1

score/testdata/pod-topology-spread-constraints-no-labelselector.yaml

@@ -0,0 +1,14 @@
+kind: Pod
+apiVersion: v1
+metadata:
+  name: mypod
+  labels:
+    foo: bar
+spec:
+  topologySpreadConstraints:
+  - maxSkew: 1
+    topologyKey: zone
+    whenUnsatisfiable: DoNotSchedule
+  containers:
+    - name: pause
+      image: registry.k8s.io/pause:3.1

score/testdata/pod-topology-spread-constraints-no-topologykey.yaml

@@ -0,0 +1,16 @@
+kind: Pod
+apiVersion: v1
+metadata:
+  name: mypod
+  labels:
+    foo: bar
+spec:
+  topologySpreadConstraints:
+  - maxSkew: 1
+    whenUnsatisfiable: DoNotSchedule
+    labelSelector:
+      matchLabels:
+        foo: bar
+  containers:
+    - name: pause
+      image: registry.k8s.io/pause:3.1

score/testdata/pod-topology-spread-constraints-one-constraint.yaml

@@ -0,0 +1,17 @@
+kind: Pod
+apiVersion: v1
+metadata:
+  name: mypod
+  labels:
+    foo: bar
+spec:
+  topologySpreadConstraints:
+  - maxSkew: 1
+    topologyKey: zone
+    whenUnsatisfiable: DoNotSchedule
+    labelSelector:
+      matchLabels:
+        foo: bar
+  containers:
+    - name: pause
+      image: registry.k8s.io/pause:3.1

score/testdata/pod-topology-spread-constraints-two-constraints.yaml

@@ -0,0 +1,23 @@
+kind: Pod
+apiVersion: v1
+metadata:
+  name: mypod
+  labels:
+    foo: bar
+spec:
+  topologySpreadConstraints:
+  - maxSkew: 1
+    topologyKey: zone
+    whenUnsatisfiable: DoNotSchedule
+    labelSelector:
+      matchLabels:
+        foo: bar
+  - maxSkew: 1
+    topologyKey: node
+    whenUnsatisfiable: DoNotSchedule
+    labelSelector:
+      matchLabels:
+        foo: bar
+  containers:
+  - name: pause
+  image: registry.k8s.io/pause:3.1