diff --git a/Makefile b/Makefile
index 4d4c396b..007e869e 100644
--- a/Makefile
+++ b/Makefile
@@ -54,7 +54,7 @@ vet: ## Run go vet against code.
 ENVTEST_ASSETS_DIR=$(shell pwd)/testbin
 test: manifests generate fmt vet ## Run tests.
 	mkdir -p ${ENVTEST_ASSETS_DIR}
-	test -f ${ENVTEST_ASSETS_DIR}/setup-envtest.sh || curl -sSLo ${ENVTEST_ASSETS_DIR}/setup-envtest.sh https://raw.githubusercontent.com/kubernetes-sigs/controller-runtime/v0.9.2/hack/setup-envtest.sh
+	test -f ${ENVTEST_ASSETS_DIR}/setup-envtest.sh || curl -sSLo ${ENVTEST_ASSETS_DIR}/setup-envtest.sh https://raw.githubusercontent.com/kubernetes-sigs/controller-runtime/v0.8.3/hack/setup-envtest.sh
 	source ${ENVTEST_ASSETS_DIR}/setup-envtest.sh; fetch_envtest_tools $(ENVTEST_ASSETS_DIR); setup_envtest_env $(ENVTEST_ASSETS_DIR); go test ./... -coverprofile cover.out
 
 ##@ Build
diff --git a/cluster/cluster.go b/cluster/cluster.go
index dfae722f..d10d0f3c 100644
--- a/cluster/cluster.go
+++ b/cluster/cluster.go
@@ -64,6 +64,8 @@ func (c *Cluster) Validate() error {
 		return fmt.Errorf("spec.mysqlOpts.user cannot be root|%s|%s|%s", utils.ReplicationUser, utils.OperatorUser, utils.MetricsUser)
 	}
 
+	// https://github.com/percona/percona-docker/blob/main/percona-server-5.7/ps-entry.sh#L159
+	// ERROR 1396 (HY000): Operation CREATE USER failed for 'root'@'127.0.0.1'.
 	if c.Spec.MysqlOpts.RootHost == "127.0.0.1" {
 		return fmt.Errorf("spec.mysqlOpts.rootHost cannot be 127.0.0.1")
 	}
diff --git a/cluster/container/init_sidecar.go b/cluster/container/init_sidecar.go
index d96bc72c..8514f340 100644
--- a/cluster/container/init_sidecar.go
+++ b/cluster/container/init_sidecar.go
@@ -87,7 +87,7 @@ func (c *initSidecar) getEnvVars() []corev1.EnvVar {
 			Value: strconv.Itoa(int(*c.Spec.XenonOpts.ElectionTimeout)),
 		},
 		{
-			Name:  "MY_MYSQL_VERSION",
+			Name:  "MYSQL_VERSION",
 			Value: c.GetMySQLVersion(),
 		},
 		getEnvVarFromSecret(sctName, "MYSQL_ROOT_PASSWORD", "root-password", false),
diff --git a/cluster/container/init_sidecar_test.go b/cluster/container/init_sidecar_test.go
index 52d961f0..687fb9b6 100644
--- a/cluster/container/init_sidecar_test.go
+++ b/cluster/container/init_sidecar_test.go
@@ -100,7 +100,7 @@ var (
 			Value: strconv.Itoa(int(*testInitSidecarCluster.Spec.XenonOpts.ElectionTimeout)),
 		},
 		{
-			Name:  "MY_MYSQL_VERSION",
+			Name:  "MYSQL_VERSION",
 			Value: "5.7.33",
 		},
 		{
diff --git a/cluster/syncer/statefulset.go b/cluster/syncer/statefulset.go
index f3d068b9..50d72660 100644
--- a/cluster/syncer/statefulset.go
+++ b/cluster/syncer/statefulset.go
@@ -401,6 +401,7 @@ func (s *StatefulSetSyncer) ensurePodSpec() corev1.PodSpec {
 	}
 }
 
+// updatePVC used to update the pvc, check and remove the extra pvc.
 func (s *StatefulSetSyncer) updatePVC(ctx context.Context) error {
 	pvcs := corev1.PersistentVolumeClaimList{}
 	if err := s.cli.List(ctx,
diff --git a/sidecar/config.go b/sidecar/config.go
index de353ac1..e4a467d1 100644
--- a/sidecar/config.go
+++ b/sidecar/config.go
@@ -87,8 +87,10 @@ func NewConfig() *Config {
 		mysqlVersion, _ = semver.Parse(utils.MySQLDefaultVersion)
 	}
 
-	replicas, err := strconv.ParseInt(getEnvValue("REPLICAS"), 10, 32)
+	replicaStr := getEnvValue("REPLICAS")
+	replicas, err := strconv.ParseInt(replicaStr, 10, 32)
 	if err != nil {
+		log.Error(err, "invalid environment values", "REPLICAS", replicaStr)
 		panic(err)
 	}