Expose a knob to configure per node eviction limits

Expose a knob to configure per node eviction limits
as we are already doing with overall evictions limit.

Signed-off-by: Simone Tiraboschi <[email protected]>

Author: tiraboschi

README.md

@@ -294,3 +294,4 @@ The Descheduler operator exposes the following parameters in its CRD:
 |`mode`|`string`|Configures the descheduler to either evict pods or to simulate the eviction|
 |`evictionLimits`|`map`|Restrict the number of evictions during each descheduling run. Available fields are: `total`|
 |`evictionLimits.total`|`int32`|Restricts the maximum number of overall evictions|
+|`evictionLimits.node`|`int32`|Restricts the maximum number of of evictions per node|

pkg/apis/descheduler/v1/types_descheduler.go

@@ -50,6 +50,9 @@ type KubeDeschedulerSpec struct {
 type EvictionLimits struct {
 	// total restricts the maximum number of overall evictions
 	Total *int32 `json:"total,omitempty"`
+
+	// node restricts the maximum number of evictions per node
+	Node *int32 `json:"node,omitempty"`
 }
 
 // ProfileCustomizations contains various parameters for modifying the default behavior of certain profiles

pkg/operator/target_config_reconciler.go

@@ -1299,6 +1299,9 @@ func (c *TargetConfigReconciler) manageConfigMap(descheduler *deschedulerv1.Kube
 		if descheduler.Spec.EvictionLimits.Total != nil {
 			policy.MaxNoOfPodsToEvictTotal = utilptr.To[uint](uint(*descheduler.Spec.EvictionLimits.Total))
 		}
+		if descheduler.Spec.EvictionLimits.Node != nil {
+			policy.MaxNoOfPodsToEvictPerNode = utilptr.To[uint](uint(*descheduler.Spec.EvictionLimits.Node))
+		}
 	}
 
 	if c.isPrometheusAsMetricsProviderForProfiles(descheduler) {

pkg/operator/target_config_reconciler_test.go

@@ -274,6 +274,23 @@ func TestManageConfigMap(t *testing.T) {
 				Data:     map[string]string{"policy.yaml": string(bindata.MustAsset("assets/lowNodeUtilizationHighConfig.yaml"))},
 			},
 		},
+		{
+			name: "LowNodeUtilizationEvictionLimits",
+			descheduler: &deschedulerv1.KubeDescheduler{
+				Spec: deschedulerv1.KubeDeschedulerSpec{
+					Profiles:              []deschedulerv1.DeschedulerProfile{"LifecycleAndUtilization"},
+					ProfileCustomizations: &deschedulerv1.ProfileCustomizations{DevLowNodeUtilizationThresholds: utilptr.To[deschedulerv1.LowNodeUtilizationThresholdsType]("")},
+					EvictionLimits: &deschedulerv1.EvictionLimits{
+						Total: utilptr.To[int32](10),
+						Node:  utilptr.To[int32](3),
+					},
+				},
+			},
+			want: &corev1.ConfigMap{
+				TypeMeta: metav1.TypeMeta{APIVersion: "v1", Kind: "ConfigMap"},
+				Data:     map[string]string{"policy.yaml": string(bindata.MustAsset("assets/lowNodeUtilizationEvictionLimits.yaml"))},
+			},
+		},
 		{
 			name: "RelieveAndMigrateWithoutCustomizations",
 			descheduler: &deschedulerv1.KubeDescheduler{

pkg/operator/testdata/assets/lowNodeUtilizationEvictionLimits.yaml

@@ -0,0 +1,71 @@
+apiVersion: descheduler/v1alpha2
+kind: DeschedulerPolicy
+maxNoOfPodsToEvictPerNode: 3
+maxNoOfPodsToEvictTotal: 10
+profiles:
+- name: LifecycleAndUtilization
+  pluginConfig:
+  - args:
+      maxPodLifeTimeSeconds: 86400
+      namespaces:
+        exclude:
+        - kube-system
+        - hypershift
+        - openshift
+        - openshift-kube-descheduler-operator
+        - openshift-kube-scheduler
+    name: PodLifeTime
+  - args:
+      includingInitContainers: true
+      namespaces:
+        exclude:
+        - kube-system
+        - hypershift
+        - openshift
+        - openshift-kube-descheduler-operator
+        - openshift-kube-scheduler
+      podRestartThreshold: 100
+    name: RemovePodsHavingTooManyRestarts
+  - args:
+      evictableNamespaces:
+        exclude:
+        - kube-system
+        - hypershift
+        - openshift
+        - openshift-kube-descheduler-operator
+        - openshift-kube-scheduler
+      targetThresholds:
+        cpu: 50
+        memory: 50
+        pods: 50
+      thresholds:
+        cpu: 20
+        memory: 20
+        pods: 20
+    name: LowNodeUtilization
+  - args:
+      ignorePvcPods: true
+    name: DefaultEvictor
+  plugins:
+    balance:
+      disabled: null
+      enabled:
+      - LowNodeUtilization
+    deschedule:
+      disabled: null
+      enabled:
+      - PodLifeTime
+      - RemovePodsHavingTooManyRestarts
+    filter:
+      disabled: null
+      enabled:
+      - DefaultEvictor
+    preevictionfilter:
+      disabled: null
+      enabled: null
+    presort:
+      disabled: null
+      enabled: null
+    sort:
+      disabled: null
+      enabled: null