diff --git a/api/v1beta1/mysqlcluster_types.go b/api/v1beta1/mysqlcluster_types.go
index 329c58a76..2835255af 100644
--- a/api/v1beta1/mysqlcluster_types.go
+++ b/api/v1beta1/mysqlcluster_types.go
@@ -397,7 +397,7 @@ func (r *MySQLCluster) ReplicaServiceName() string {
 
 // PodHostname returns the hostname of a Pod with the given index.
 func (r *MySQLCluster) PodHostname(index int) string {
-	return fmt.Sprintf("%s.%s.%s.svc", r.PodName(index), r.PrefixedName(), r.Namespace)
+	return fmt.Sprintf("%s.%s.%s.svc", r.PodName(index), r.HeadlessServiceName(), r.Namespace)
 }
 
 // SlowQueryLogAgentConfigMapName returns the name of the slow query log agent config name.
diff --git a/clustering/manager.go b/clustering/manager.go
index a826fdd50..20765dbd5 100644
--- a/clustering/manager.go
+++ b/clustering/manager.go
@@ -5,7 +5,6 @@ import (
 	"sync"
 	"time"
 
-	mocov1beta1 "github.com/cybozu-go/moco/api/v1beta1"
 	"github.com/cybozu-go/moco/pkg/dbop"
 	"github.com/go-logr/logr"
 	_ "github.com/go-sql-driver/mysql"
@@ -24,7 +23,7 @@ import (
 //
 // This interface is meant to be used by MySQLClusterReconciler.
 type ClusterManager interface {
-	Update(context.Context, *mocov1beta1.MySQLCluster)
+	Update(context.Context, types.NamespacedName)
 	Stop(types.NamespacedName)
 }
 
@@ -56,11 +55,10 @@ type clusterManager struct {
 	processes map[string]*managerProcess
 }
 
-func (m *clusterManager) Update(ctx context.Context, cluster *mocov1beta1.MySQLCluster) {
+func (m *clusterManager) Update(ctx context.Context, name types.NamespacedName) {
 	m.mu.Lock()
 	defer m.mu.Unlock()
 
-	name := client.ObjectKeyFromObject(cluster)
 	key := name.String()
 	p, ok := m.processes[key]
 	if ok {
diff --git a/clustering/manager_test.go b/clustering/manager_test.go
index bee26e24c..2b5838e34 100644
--- a/clustering/manager_test.go
+++ b/clustering/manager_test.go
@@ -153,7 +153,7 @@ var _ = Describe("manager", func() {
 
 		cluster, err := testGetCluster(ctx)
 		Expect(err).NotTo(HaveOccurred())
-		cm.Update(ctx, cluster)
+		cm.Update(ctx, client.ObjectKeyFromObject(cluster))
 
 		Eventually(func() error {
 			cluster, err = testGetCluster(ctx)
@@ -273,7 +273,7 @@ var _ = Describe("manager", func() {
 		cm := NewClusterManager(1*time.Second, mgr, of, af, stdr.New(nil))
 		cluster, err := testGetCluster(ctx)
 		Expect(err).NotTo(HaveOccurred())
-		cm.Update(ctx, cluster)
+		cm.Update(ctx, client.ObjectKeyFromObject(cluster))
 		defer func() {
 			cm.Stop(client.ObjectKeyFromObject(cluster))
 			time.Sleep(400 * time.Millisecond)
@@ -614,7 +614,7 @@ var _ = Describe("manager", func() {
 		cm := NewClusterManager(1*time.Second, mgr, of, af, stdr.New(nil))
 		cluster, err := testGetCluster(ctx)
 		Expect(err).NotTo(HaveOccurred())
-		cm.Update(ctx, cluster)
+		cm.Update(ctx, client.ObjectKeyFromObject(cluster))
 		defer func() {
 			cm.Stop(client.ObjectKeyFromObject(cluster))
 			time.Sleep(400 * time.Millisecond)
diff --git a/clustering/status.go b/clustering/status.go
index 0e5ae3a70..b55d7da10 100644
--- a/clustering/status.go
+++ b/clustering/status.go
@@ -91,7 +91,9 @@ type StatusSet struct {
 // Close closes `ss.DBOps`.
 func (ss *StatusSet) Close() {
 	for _, op := range ss.DBOps {
-		op.Close()
+		if op != nil {
+			op.Close()
+		}
 	}
 }
 
@@ -163,6 +165,11 @@ func (p *managerProcess) GatherStatus(ctx context.Context) (*StatusSet, error) {
 	}
 
 	ss.DBOps = make([]dbop.Operator, cluster.Spec.Replicas)
+	defer func() {
+		if ss.State == StateUndecided {
+			ss.Close()
+		}
+	}()
 	for i := 0; i < int(cluster.Spec.Replicas); i++ {
 		op, err := p.dbf.New(ctx, cluster, passwd, i)
 		if err != nil {
@@ -170,11 +177,6 @@ func (p *managerProcess) GatherStatus(ctx context.Context) (*StatusSet, error) {
 		}
 		ss.DBOps[i] = op
 	}
-	defer func() {
-		if ss.State == StateUndecided {
-			ss.Close()
-		}
-	}()
 
 	ss.MySQLStatus = make([]*dbop.MySQLInstanceStatus, cluster.Spec.Replicas)
 	var wg sync.WaitGroup
diff --git a/controllers/mysql_container.go b/controllers/mysql_container.go
index c071a932b..fe9c4ba55 100644
--- a/controllers/mysql_container.go
+++ b/controllers/mysql_container.go
@@ -153,10 +153,12 @@ func (r *MySQLClusterReconciler) makeV1AgentContainer(cluster *mocov1beta1.MySQL
 	return c
 }
 
-func (r *MySQLClusterReconciler) makeV1SlowQueryLogContainer(sts *appsv1.StatefulSet) corev1.Container {
-	for _, c := range sts.Spec.Template.Spec.Containers {
-		if c.Name == constants.SlowQueryLogAgentContainerName {
-			return c
+func (r *MySQLClusterReconciler) makeV1SlowQueryLogContainer(sts *appsv1.StatefulSet, force bool) corev1.Container {
+	if !force {
+		for _, c := range sts.Spec.Template.Spec.Containers {
+			if c.Name == constants.SlowQueryLogAgentContainerName {
+				return c
+			}
 		}
 	}
 
diff --git a/controllers/mysqlcluster_controller.go b/controllers/mysqlcluster_controller.go
index 884088d08..e6b3eef72 100644
--- a/controllers/mysqlcluster_controller.go
+++ b/controllers/mysqlcluster_controller.go
@@ -191,7 +191,7 @@ func (r *MySQLClusterReconciler) reconcileV1(ctx context.Context, req ctrl.Reque
 		}
 	}
 
-	r.ClusterManager.Update(ctx, cluster)
+	r.ClusterManager.Update(ctx, client.ObjectKeyFromObject(cluster))
 	return ctrl.Result{}, nil
 }
 
@@ -476,6 +476,7 @@ func (r *MySQLClusterReconciler) reconcileV1Service1(ctx context.Context, cluste
 		if headless {
 			saSpec.ClusterIP = corev1.ClusterIPNone
 			saSpec.Type = corev1.ServiceTypeClusterIP
+			saSpec.PublishNotReadyAddresses = true
 		} else {
 			saSpec.ClusterIP = svc.Spec.ClusterIP
 			if len(saSpec.Type) == 0 {
@@ -557,7 +558,7 @@ func (r *MySQLClusterReconciler) reconcileV1StatefulSet(ctx context.Context, req
 			MatchLabels: labelSet(cluster, false),
 		}
 		sts.Spec.PodManagementPolicy = appsv1.ParallelPodManagement
-		sts.Spec.ServiceName = cluster.PrefixedName()
+		sts.Spec.ServiceName = cluster.HeadlessServiceName()
 
 		sts.Spec.VolumeClaimTemplates = make([]corev1.PersistentVolumeClaim, len(cluster.Spec.VolumeClaimTemplates))
 		for i, v := range cluster.Spec.VolumeClaimTemplates {
@@ -654,7 +655,8 @@ func (r *MySQLClusterReconciler) reconcileV1StatefulSet(ctx context.Context, req
 		containers = append(containers, mysqldContainer)
 		containers = append(containers, r.makeV1AgentContainer(cluster, sts.Spec.Template.Spec.Containers))
 		if !cluster.Spec.DisableSlowQueryLogContainer {
-			containers = append(containers, r.makeV1SlowQueryLogContainer(sts))
+			force := cluster.Status.ReconcileInfo.Generation != cluster.Generation
+			containers = append(containers, r.makeV1SlowQueryLogContainer(sts, force))
 		}
 		containers = append(containers, r.makeV1OptionalContainers(cluster, sts.Spec.Template.Spec.Containers)...)
 		podSpec.Containers = containers
diff --git a/controllers/mysqlcluster_controller_test.go b/controllers/mysqlcluster_controller_test.go
index 9a2f6eecf..c900b8834 100644
--- a/controllers/mysqlcluster_controller_test.go
+++ b/controllers/mysqlcluster_controller_test.go
@@ -32,11 +32,10 @@ type mockManager struct {
 
 var _ clustering.ClusterManager = &mockManager{}
 
-func (m *mockManager) Update(ctx context.Context, cluster *mocov1beta1.MySQLCluster) {
+func (m *mockManager) Update(ctx context.Context, key types.NamespacedName) {
 	m.mu.Lock()
 	defer m.mu.Unlock()
 
-	key := client.ObjectKeyFromObject(cluster)
 	m.clusters[key.String()] = struct{}{}
 }
 
@@ -454,6 +453,8 @@ var _ = Describe("MySQLCluster reconciler", func() {
 		Expect(primary.Spec.Selector).To(HaveKeyWithValue("moco.cybozu.com/role", "primary"))
 		Expect(replica.Spec.Selector).To(HaveKeyWithValue("moco.cybozu.com/role", "replica"))
 
+		Expect(headless.Spec.PublishNotReadyAddresses).To(BeTrue())
+
 		cluster = &mocov1beta1.MySQLCluster{}
 		err = k8sClient.Get(ctx, client.ObjectKey{Namespace: "test", Name: "test"}, cluster)
 		Expect(err).NotTo(HaveOccurred())
diff --git a/docs/reconcile.md b/docs/reconcile.md
index 1ba4d5600..6486984e7 100644
--- a/docs/reconcile.md
+++ b/docs/reconcile.md
@@ -26,7 +26,7 @@ It updates the StatefulSet only when the update is a must.
 
 The StatefulSet will be updated when:
 
-- The fields under `spec` of MySQLCluster are modified.
+- Some fields under `spec` of MySQLCluster are modified.
 - `my.cnf` for mysqld is updated.
 - the version of the reconciler used to reconcile the StatefulSet is obsoleted.
 - the image of moco-agent given to the controller is updated.
@@ -36,6 +36,9 @@ The StatefulSet will be updated when:
 - the image of fluent-bit given to the controller is changed.
     - because the controller does not depend on fluent-bit.
 
+The fluent-bit sidecar container is updated only when some fields under
+`spec` of MySQLCluster are modified.
+
 ## Service
 
 MOCO creates three Services for each MySQLCluster, that is:
diff --git a/e2e/lifecycle_test.go b/e2e/lifecycle_test.go
index f54c0f092..8207e7779 100644
--- a/e2e/lifecycle_test.go
+++ b/e2e/lifecycle_test.go
@@ -198,5 +198,20 @@ var _ = Context("lifecycle", func() {
 			}
 			return fmt.Errorf("pending service accounts: %+v", sas.Items)
 		}).Should(Succeed())
+		Eventually(func() error {
+			services := &corev1.ServiceList{}
+			out, err := kubectl(nil, "-n", "foo", "get", "service", "-o", "json")
+			if err != nil {
+				return err
+			}
+			err = json.Unmarshal(out, services)
+			if err != nil {
+				return err
+			}
+			if len(services.Items) == 0 {
+				return nil
+			}
+			return fmt.Errorf("pending services: %+v", services.Items)
+		}).Should(Succeed())
 	})
 })
diff --git a/pkg/constants/constants.go b/pkg/constants/constants.go
index 9e4636334..c933a4f82 100644
--- a/pkg/constants/constants.go
+++ b/pkg/constants/constants.go
@@ -57,7 +57,7 @@ const (
 	FluentBitConfigPath = "/fluent-bit/etc"
 )
 
-// Environment variables for moco-agent
+// Environment variables
 const (
 	PodNameEnvKey      = "POD_NAME"
 	PodNamespaceEnvKey = "POD_NAMESPACE"
diff --git a/pkg/dbop/operator.go b/pkg/dbop/operator.go
index d136cdba2..06a0a20bf 100644
--- a/pkg/dbop/operator.go
+++ b/pkg/dbop/operator.go
@@ -95,9 +95,9 @@ func (f defaultFactory) New(ctx context.Context, cluster *mocov1beta1.MySQLClust
 	cfg.ParseTime = true
 	cfg.Timeout = connTimeout
 	cfg.ReadTimeout = readTimeout
-	db, err := sqlx.Connect("mysql", cfg.FormatDSN())
+	db, err := sqlx.Open("mysql", cfg.FormatDSN())
 	if err != nil {
-		return nil, fmt.Errorf("failed to connect to %s: %w", cluster.PodName(index), err)
+		return nil, fmt.Errorf("failed to open %s: %w", cluster.PodName(index), err)
 	}
 	db.SetMaxIdleConns(1)
 	db.SetConnMaxIdleTime(30 * time.Second)
diff --git a/pkg/password/password.go b/pkg/password/password.go
index 6b19aba7f..5ab8e34f4 100644
--- a/pkg/password/password.go
+++ b/pkg/password/password.go
@@ -20,8 +20,8 @@ const (
 	agentPasswordKey       = "AGENT_PASSWORD"
 	replicationPasswordKey = "REPLICATION_PASSWORD"
 	cloneDonorPasswordKey  = "CLONE_DONOR_PASSWORD"
-	ReadOnlyPasswordKey    = "READONLY_PASSWORD"
-	WritablePasswordKey    = "WRITABLE_PASSWORD"
+	readOnlyPasswordKey    = "READONLY_PASSWORD"
+	writablePasswordKey    = "WRITABLE_PASSWORD"
 )
 
 // MySQLPassword represents a set of passwords of MySQL users for MOCO
@@ -87,8 +87,8 @@ func NewMySQLPasswordFromSecret(secret *corev1.Secret) (*MySQLPassword, error) {
 		agent:      string(secret.Data[agentPasswordKey]),
 		replicator: string(secret.Data[replicationPasswordKey]),
 		donor:      string(secret.Data[cloneDonorPasswordKey]),
-		readOnly:   string(secret.Data[ReadOnlyPasswordKey]),
-		writable:   string(secret.Data[WritablePasswordKey]),
+		readOnly:   string(secret.Data[readOnlyPasswordKey]),
+		writable:   string(secret.Data[writablePasswordKey]),
 	}, nil
 }
 
@@ -106,8 +106,8 @@ func (p MySQLPassword) ToSecret() *corev1.Secret {
 			agentPasswordKey:       []byte(p.agent),
 			replicationPasswordKey: []byte(p.replicator),
 			cloneDonorPasswordKey:  []byte(p.donor),
-			ReadOnlyPasswordKey:    []byte(p.readOnly),
-			WritablePasswordKey:    []byte(p.writable),
+			readOnlyPasswordKey:    []byte(p.readOnly),
+			writablePasswordKey:    []byte(p.writable),
 		},
 	}
 }
@@ -129,9 +129,9 @@ password="%s"
 			},
 		},
 		Data: map[string][]byte{
+			constants.AdminMyCnf:    formatMyCnf(constants.AdminUser, p.admin),
 			constants.ReadOnlyMyCnf: formatMyCnf(constants.ReadOnlyUser, p.readOnly),
 			constants.WritableMyCnf: formatMyCnf(constants.WritableUser, p.writable),
-			constants.AdminMyCnf:    formatMyCnf(constants.AdminUser, p.admin),
 		},
 	}
 }