Use MaxUnavailable for PDB

Author: mrkm4ntr

pkg/controller/elasticsearch/pdb/reconcile.go

@@ -162,12 +162,7 @@ func expectedPDB(es esv1.Elasticsearch, statefulSets sset.StatefulSetList) (*pol
 // buildPDBSpec returns a PDBSpec computed from the current StatefulSets,
 // considering the cluster health and topology.
 func buildPDBSpec(es esv1.Elasticsearch, statefulSets sset.StatefulSetList) policyv1.PodDisruptionBudgetSpec {
-	// compute MinAvailable based on the maximum number of Pods we're supposed to have
-	nodeCount := statefulSets.ExpectedNodeCount()
-	// maybe allow some Pods to be disrupted
-	minAvailable := nodeCount - allowedDisruptions(es, statefulSets)
-
-	minAvailableIntStr := intstr.IntOrString{Type: intstr.Int, IntVal: minAvailable}
+	maxUnavailableIntStr := intstr.IntOrString{Type: intstr.Int, IntVal: allowedDisruptions(es, statefulSets)}
 
 	return policyv1.PodDisruptionBudgetSpec{
 		// match all pods for this cluster
@@ -176,10 +171,8 @@ func buildPDBSpec(es esv1.Elasticsearch, statefulSets sset.StatefulSetList) poli
 				label.ClusterNameLabelName: es.Name,
 			},
 		},
-		MinAvailable: &minAvailableIntStr,
-		// MaxUnavailable can only be used if the selector matches a builtin controller selector
-		// (eg. Deployments, StatefulSets, etc.). We cannot use it with our own cluster-name selector.
-		MaxUnavailable: nil,
+		MaxUnavailable: &maxUnavailableIntStr,
+		MinAvailable:   nil,
 	}
 }
 

pkg/controller/elasticsearch/pdb/reconcile_test.go

@@ -40,13 +40,13 @@ func TestReconcile(t *testing.T) {
 				Labels:    map[string]string{label.ClusterNameLabelName: "cluster", commonv1.TypeLabelName: label.Type},
 			},
 			Spec: policyv1.PodDisruptionBudgetSpec{
-				MinAvailable: intStrPtr(intstr.FromInt(3)),
+				MaxUnavailable: intStrPtr(intstr.FromInt(0)),
 				Selector: &metav1.LabelSelector{
 					MatchLabels: map[string]string{
 						label.ClusterNameLabelName: "cluster",
 					},
 				},
-				MaxUnavailable: nil,
+				MinAvailable: nil,
 			},
 		}
 	}
@@ -79,7 +79,7 @@ func TestReconcile(t *testing.T) {
 			wantPDB: defaultPDB(),
 		},
 		{
-			name: "pdb needs a MinAvailable update",
+			name: "pdb doesn't need a MaxUnavailable update",
 			args: args{
 				initObjs:     []client.Object{defaultPDB()},
 				es:           defaultEs,
@@ -92,13 +92,13 @@ func TestReconcile(t *testing.T) {
 					Labels:    map[string]string{label.ClusterNameLabelName: "cluster", commonv1.TypeLabelName: label.Type},
 				},
 				Spec: policyv1.PodDisruptionBudgetSpec{
-					MinAvailable: intStrPtr(intstr.FromInt(5)),
+					MaxUnavailable: intStrPtr(intstr.FromInt(0)),
 					Selector: &metav1.LabelSelector{
 						MatchLabels: map[string]string{
 							label.ClusterNameLabelName: "cluster",
 						},
 					},
-					MaxUnavailable: nil,
+					MinAvailable: nil,
 				},
 			},
 		},
@@ -196,13 +196,13 @@ func Test_expectedPDB(t *testing.T) {
 					Labels:    map[string]string{label.ClusterNameLabelName: "cluster", commonv1.TypeLabelName: label.Type},
 				},
 				Spec: policyv1.PodDisruptionBudgetSpec{
-					MinAvailable: intStrPtr(intstr.FromInt(3)),
+					MaxUnavailable: intStrPtr(intstr.FromInt(0)),
 					Selector: &metav1.LabelSelector{
 						MatchLabels: map[string]string{
 							label.ClusterNameLabelName: "cluster",
 						},
 					},
-					MaxUnavailable: nil,
+					MinAvailable: nil,
 				},
 			},
 		},
@@ -227,13 +227,13 @@ func Test_expectedPDB(t *testing.T) {
 					Labels:    map[string]string{"a": "b", "c": "d", label.ClusterNameLabelName: "cluster", commonv1.TypeLabelName: label.Type},
 				},
 				Spec: policyv1.PodDisruptionBudgetSpec{
-					MinAvailable: intStrPtr(intstr.FromInt(3)),
+					MaxUnavailable: intStrPtr(intstr.FromInt(0)),
 					Selector: &metav1.LabelSelector{
 						MatchLabels: map[string]string{
 							label.ClusterNameLabelName: "cluster",
 						},
 					},
-					MaxUnavailable: nil,
+					MinAvailable: nil,
 				},
 			},
 		},