From 8ca40b6ff66c9bd0a56825e8f5bb1ea6ac9b8a19 Mon Sep 17 00:00:00 2001
From: Michael Burman <yak@iki.fi>
Date: Wed, 27 Mar 2024 17:46:19 +0200
Subject: [PATCH] If service is already owned by some other resource, do not
 try to take ownership of it. If it later gets deleted because of cleanup, we
 will recreate it

---
 CHANGELOG.md                             |  1 +
 pkg/reconciliation/reconcile_services.go | 19 +++++++++----------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 516fcccce..10c6a945d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@ Changelog for Cass Operator, new PRs should update the `main / unreleased` secti
 * [CHANGE] [#618](https://github.com/k8ssandra/cass-operator/issues/618) Update dependencies to support controller-runtime 0.17.2, modify required parts.
 * [ENHANCEMENT] [#532](https://github.com/k8ssandra/cass-operator/issues/532) Instead of rejecting updates/creates with deprecated fields, return kubectl warnings.
 * [BUGFIX] [#622](https://github.com/k8ssandra/cass-operator/issues/622) Fix sanitization of DC label
+* [BUGFIX] [#626](https://github.com/k8ssandra/cass-operator/issues/626) If multiple datacenters are present in the same namespace, the seed-service ownership is constantly updated between these two resources
 
 ## v1.19.0
 
diff --git a/pkg/reconciliation/reconcile_services.go b/pkg/reconciliation/reconcile_services.go
index 9e9f67196..bf278af21 100644
--- a/pkg/reconciliation/reconcile_services.go
+++ b/pkg/reconciliation/reconcile_services.go
@@ -9,6 +9,7 @@ import (
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/types"
+	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
 
 	"github.com/k8ssandra/cass-operator/pkg/utils"
 )
@@ -72,29 +73,27 @@ func (rc *ReconciliationContext) CheckHeadlessServices() result.ReconcileResult
 	for idx := range services {
 		desiredSvc := services[idx]
 
-		// Set CassandraDatacenter dc as the owner and controller
-		err := setControllerReference(dc, desiredSvc, rc.Scheme)
-		if err != nil {
-			logger.Error(err, "Could not set controller reference for headless service")
-			return result.Error(err)
+		// If the service is already owned by some other resource, do not try to take ownership - otherwise resources will fight for control.
+		if !controllerutil.HasControllerReference(desiredSvc) {
+			// Set CassandraDatacenter dc as the owner and controller
+			if err := setControllerReference(dc, desiredSvc, rc.Scheme); err != nil {
+				logger.Error(err, "Could not set controller reference for headless service")
+				return result.Error(err)
+			}
 		}
 
 		// See if the service already exists
 		nsName := types.NamespacedName{Name: desiredSvc.Name, Namespace: desiredSvc.Namespace}
 		currentService := &corev1.Service{}
-		err = client.Get(rc.Ctx, nsName, currentService)
-
-		if err != nil && errors.IsNotFound(err) {
+		if err := client.Get(rc.Ctx, nsName, currentService); err != nil && errors.IsNotFound(err) {
 			// if it's not found, put the service in the slice to be created when Apply is called
 			createNeeded = append(createNeeded, desiredSvc)
-
 		} else if err != nil {
 			// if we hit a k8s error, log it and error out
 			logger.Error(err, "Could not get headless seed service",
 				"name", nsName,
 			)
 			return result.Error(err)
-
 		} else {
 			// if we found the service already, check if they need updating
 			if !utils.ResourcesHaveSameHash(currentService, desiredSvc) {