Fix a bug where a process group with the same ID could be generated

api/v1beta2/foundationdbcluster_types.go

@@ -2957,6 +2957,8 @@ func (cluster *FoundationDBCluster) GetNextRandomProcessGroupID(processClass Pro
 			continue
 		}
 
+		// Add the newly picked process group ID.
+		processGroupIDs[idNum] = true
 		// The randomly picked process group is not in use and is not marked for removal, so we can use it.
 		break
 	}

controllers/add_process_groups.go

@@ -56,6 +56,11 @@ func (a addProcessGroups) reconcile(ctx context.Context, r *FoundationDBClusterR
 			continue
 		}
 
+		_, ok := processGroupIDs[processClass]
+		if !ok {
+			processGroupIDs[processClass] = map[int]bool{}
+		}
+
 		hasNewProcessGroups = true
 		logger.Info("Adding new Process Groups", "processClass", processClass, "newCount", newCount, "desiredCount", desiredCount, "currentCount", processCounts[processClass])
 		r.Recorder.Event(cluster, corev1.EventTypeNormal, "AddingProcesses", fmt.Sprintf("Adding %d %s processes", newCount, processClass))

controllers/add_process_groups_test.go

@@ -64,7 +64,7 @@ var _ = Describe("add_process_groups", func() {
 		newProcessCounts = fdbv1beta2.CreateProcessCountsFromProcessGroupStatus(cluster.Status.ProcessGroups, true)
 	})
 
-	Context("with a reconciled cluster", func() {
+	When("the cluster is reconciled", func() {
 		It("should not requeue", func() {
 			Expect(requeue).To(BeNil())
 		})
@@ -190,4 +190,28 @@ var _ = Describe("add_process_groups", func() {
 			Expect(processGroupStatus.ProcessGroupConditions[2].ProcessGroupConditionType).To(Equal(fdbv1beta2.MissingPVC))
 		})
 	})
+
+	When("multiple process groups should be created", func() {
+		var storageProcessCount int
+
+		BeforeEach(func() {
+			// The maximum is 99999, so creating 25000 process groups should have a high probability to randomly generate
+			// a used process group ID.
+			storageProcessCount = 25000
+			cluster.Spec.ProcessCounts.Storage = storageProcessCount
+		})
+
+		It("should not create duplicate entries", func() {
+			storageProcessGroups := map[fdbv1beta2.ProcessGroupID]fdbv1beta2.None{}
+			for _, processGroup := range cluster.Status.ProcessGroups {
+				if processGroup.ProcessClass != fdbv1beta2.ProcessClassStorage {
+					continue
+				}
+
+				storageProcessGroups[processGroup.ProcessGroupID] = fdbv1beta2.None{}
+			}
+
+			Expect(storageProcessGroups).To(HaveLen(storageProcessCount))
+		})
+	})
 })