diff --git a/internal/mysql/node.go b/internal/mysql/node.go
index ed1966ad..4dcdd053 100644
--- a/internal/mysql/node.go
+++ b/internal/mysql/node.go
@@ -29,7 +29,7 @@ import (
 
 // Node represents API to query/manipulate single MySQL node
 type Node struct {
-	Config  *config.Config
+	config  *config.Config
 	logger  *log.Logger
 	host    string
 	db      *sqlx.DB
@@ -65,7 +65,7 @@ func NewNode(config *config.Config, logger *log.Logger, host string) (*Node, err
 	db.SetMaxOpenConns(3)
 	db.SetConnMaxLifetime(3 * config.TickInterval)
 	return &Node{
-		Config:  config,
+		config:  config,
 		logger:  logger,
 		db:      db,
 		host:    host,
@@ -97,7 +97,7 @@ func (n *Node) Host() string {
 
 // IsLocal returns true if MySQL Node running on the same host as calling mysync process
 func (n *Node) IsLocal() bool {
-	return n.host == n.Config.Hostname
+	return n.host == n.config.Hostname
 }
 
 func (n *Node) String() string {
@@ -110,7 +110,7 @@ func (n *Node) Close() error {
 }
 
 func (n *Node) getCommand(name string) string {
-	command, ok := n.Config.Commands[name]
+	command, ok := n.config.Commands[name]
 	if !ok {
 		command, ok = defaultCommands[name]
 	}
@@ -134,7 +134,7 @@ func (n *Node) runCommand(name string) (int, error) {
 }
 
 func (n *Node) getQuery(name string) string {
-	query, ok := n.Config.Queries[name]
+	query, ok := n.config.Queries[name]
 	if !ok {
 		query, ok = DefaultQueries[name]
 	}
@@ -147,14 +147,14 @@ func (n *Node) getQuery(name string) string {
 func (n *Node) traceQuery(query string, arg interface{}, result interface{}, err error) {
 	query = queryOnliner.ReplaceAllString(query, " ")
 	msg := fmt.Sprintf("node %s running query '%s' with args %#v, result: %#v, error: %v", n.host, query, arg, result, err)
-	msg = strings.Replace(msg, n.Config.MySQL.Password, "********", -1)
-	msg = strings.Replace(msg, n.Config.MySQL.ReplicationPassword, "********", -1)
+	msg = strings.Replace(msg, n.config.MySQL.Password, "********", -1)
+	msg = strings.Replace(msg, n.config.MySQL.ReplicationPassword, "********", -1)
 	n.logger.Debug(msg)
 }
 
 //nolint:unparam
 func (n *Node) QueryRow(queryName string, arg interface{}, result interface{}) error {
-	return n.queryRowWithTimeout(queryName, arg, result, n.Config.DBTimeout)
+	return n.queryRowWithTimeout(queryName, arg, result, n.config.DBTimeout)
 }
 
 func (n *Node) queryRowWithTimeout(queryName string, arg interface{}, result interface{}, timeout time.Duration) error {
@@ -186,7 +186,7 @@ func (n *Node) QueryRows(queryName string, arg interface{}, scanner func(*sqlx.R
 		arg = struct{}{}
 	}
 	query := n.getQuery(queryName)
-	ctx, cancel := context.WithTimeout(context.Background(), n.Config.DBTimeout)
+	ctx, cancel := context.WithTimeout(context.Background(), n.config.DBTimeout)
 	defer cancel()
 	rows, err := n.db.NamedQueryContext(ctx, query, arg)
 	n.traceQuery(query, arg, rows, err)
@@ -225,7 +225,7 @@ func (n *Node) execWithTimeout(queryName string, arg map[string]interface{}, tim
 
 // nolint: unparam
 func (n *Node) Exec(queryName string, arg map[string]interface{}) error {
-	return n.execWithTimeout(queryName, arg, n.Config.DBTimeout)
+	return n.execWithTimeout(queryName, arg, n.config.DBTimeout)
 }
 
 func (n *Node) getRunningQueryIds(excludeUsers []string, timeout time.Duration) ([]int, error) {
@@ -304,7 +304,7 @@ func (n *Node) execMogrifyWithTimeout(queryName string, arg map[string]interface
 }
 
 func (n *Node) ExecMogrify(queryName string, arg map[string]interface{}) error {
-	return n.execMogrifyWithTimeout(queryName, arg, n.Config.DBTimeout)
+	return n.execMogrifyWithTimeout(queryName, arg, n.config.DBTimeout)
 }
 
 func (n *Node) queryRowMogrifyWithTimeout(queryName string, arg map[string]interface{}, result interface{}, timeout time.Duration) error {
@@ -352,15 +352,15 @@ func (n *Node) getTestDiskUsage(f string) (used uint64, total uint64, err error)
 
 // GetDiskUsage returns datadir usage statistics
 func (n *Node) GetDiskUsage() (used uint64, total uint64, err error) {
-	if n.Config.TestDiskUsageFile != "" {
-		return n.getTestDiskUsage(n.Config.TestDiskUsageFile)
+	if n.config.TestDiskUsageFile != "" {
+		return n.getTestDiskUsage(n.config.TestDiskUsageFile)
 	}
 	if !n.IsLocal() {
 		err = ErrNotLocalNode
 		return
 	}
 	var stat syscall.Statfs_t
-	err = syscall.Statfs(n.Config.MySQL.DataDir, &stat)
+	err = syscall.Statfs(n.config.MySQL.DataDir, &stat)
 	total = uint64(stat.Bsize) * stat.Blocks
 	// on FreeBSD stat.Bavail may be negative
 	bavail := stat.Bavail
@@ -406,8 +406,8 @@ func getFlagsFromProcMounts(file, filesystem string) (string, error) {
 }
 
 func (n *Node) IsFileSystemReadonly() (bool, error) {
-	if n.Config.TestFilesystemReadonlyFile != "" {
-		return n.isTestFileSystemReadonly(n.Config.TestFilesystemReadonlyFile)
+	if n.config.TestFilesystemReadonlyFile != "" {
+		return n.isTestFileSystemReadonly(n.config.TestFilesystemReadonlyFile)
 	}
 	if !n.IsLocal() {
 		return false, ErrNotLocalNode
@@ -419,7 +419,7 @@ func (n *Node) IsFileSystemReadonly() (bool, error) {
 	}
 	file := string(data)
 
-	flag, err := getFlagsFromProcMounts(file, n.Config.MySQL.DataDir)
+	flag, err := getFlagsFromProcMounts(file, n.config.MySQL.DataDir)
 	if err != nil {
 		return false, err
 	}
@@ -435,7 +435,7 @@ func (n *Node) GetDaemonStartTime() (time.Time, error) {
 	if !n.IsLocal() {
 		return time.Time{}, ErrNotLocalNode
 	}
-	pidB, err := os.ReadFile(n.Config.MySQL.PidFile)
+	pidB, err := os.ReadFile(n.config.MySQL.PidFile)
 	if err != nil {
 		if os.IsNotExist(err) {
 			err = nil
@@ -461,7 +461,7 @@ func (n *Node) GetCrashRecoveryTime() (time.Time, error) {
 	if !n.IsLocal() {
 		return time.Time{}, ErrNotLocalNode
 	}
-	fh, err := os.Open(n.Config.MySQL.ErrorLog)
+	fh, err := os.Open(n.config.MySQL.ErrorLog)
 	if err != nil {
 		return time.Time{}, err
 	}
@@ -594,7 +594,7 @@ func (n *Node) IsReadOnly() (bool, bool, error) {
 // Setting server read-only may take a while
 // as server waits all running commits (not transactions) to be finished
 func (n *Node) SetReadOnly(superReadOnly bool) error {
-	return n.setReadonlyWithTimeout(superReadOnly, n.Config.DBSetRoTimeout)
+	return n.setReadonlyWithTimeout(superReadOnly, n.config.DBSetRoTimeout)
 }
 
 func (n *Node) setReadonlyWithTimeout(superReadOnly bool, timeout time.Duration) error {
@@ -661,7 +661,7 @@ func (n *Node) SetReadOnlyWithForce(excludeUsers []string, superReadOnly bool) e
 
 	defer func() { quit <- true }()
 
-	return n.setReadonlyWithTimeout(superReadOnly, n.Config.DBSetRoForceTimeout)
+	return n.setReadonlyWithTimeout(superReadOnly, n.config.DBSetRoForceTimeout)
 }
 
 // SetWritable sets MySQL Node to be writable, eg. disables read-only
@@ -672,28 +672,28 @@ func (n *Node) SetWritable() error {
 // StopSlave stops replication (both IO and SQL threads)
 func (n *Node) StopSlave() error {
 	return n.execMogrifyWithTimeout(queryStopSlave, map[string]interface{}{
-		"channel": n.Config.ReplicationChannel,
-	}, n.Config.DBStopSlaveSQLThreadTimeout)
+		"channel": n.config.ReplicationChannel,
+	}, n.config.DBStopSlaveSQLThreadTimeout)
 }
 
 // StartSlave starts replication (both IO and SQL threads)
 func (n *Node) StartSlave() error {
 	return n.ExecMogrify(queryStartSlave, map[string]interface{}{
-		"channel": n.Config.ReplicationChannel,
+		"channel": n.config.ReplicationChannel,
 	})
 }
 
 // StopSlaveIOThread stops IO replication thread
 func (n *Node) StopSlaveIOThread() error {
 	return n.ExecMogrify(queryStopSlaveIOThread, map[string]interface{}{
-		"channel": n.Config.ReplicationChannel,
+		"channel": n.config.ReplicationChannel,
 	})
 }
 
 // StartSlaveIOThread starts IO replication thread
 func (n *Node) StartSlaveIOThread() error {
 	return n.ExecMogrify(queryStartSlaveIOThread, map[string]interface{}{
-		"channel": n.Config.ReplicationChannel,
+		"channel": n.config.ReplicationChannel,
 	})
 }
 
@@ -709,21 +709,21 @@ func (n *Node) RestartSlaveIOThread() error {
 // StopSlaveSQLThread stops SQL replication thread
 func (n *Node) StopSlaveSQLThread() error {
 	return n.execMogrifyWithTimeout(queryStopSlaveSQLThread, map[string]interface{}{
-		"channel": n.Config.ReplicationChannel,
-	}, n.Config.DBStopSlaveSQLThreadTimeout)
+		"channel": n.config.ReplicationChannel,
+	}, n.config.DBStopSlaveSQLThreadTimeout)
 }
 
 // StartSlaveSQLThread starts SQL replication thread
 func (n *Node) StartSlaveSQLThread() error {
 	return n.ExecMogrify(queryStartSlaveSQLThread, map[string]interface{}{
-		"channel": n.Config.ReplicationChannel,
+		"channel": n.config.ReplicationChannel,
 	})
 }
 
 // ResetSlaveAll promotes MySQL Node to be master
 func (n *Node) ResetSlaveAll() error {
 	return n.ExecMogrify(queryResetSlaveAll, map[string]interface{}{
-		"channel": n.Config.ReplicationChannel,
+		"channel": n.config.ReplicationChannel,
 	})
 }
 
@@ -784,20 +784,20 @@ func (n *Node) SetOnline() error {
 // ChangeMaster changes master of MySQL Node, demoting it to slave
 func (n *Node) ChangeMaster(host string) error {
 	useSsl := 0
-	if n.Config.MySQL.ReplicationSslCA != "" {
+	if n.config.MySQL.ReplicationSslCA != "" {
 		useSsl = 1
 	}
 	return n.ExecMogrify(queryChangeMaster, map[string]interface{}{
 		"host":            host,
-		"port":            n.Config.MySQL.ReplicationPort,
-		"user":            n.Config.MySQL.ReplicationUser,
-		"password":        n.Config.MySQL.ReplicationPassword,
+		"port":            n.config.MySQL.ReplicationPort,
+		"user":            n.config.MySQL.ReplicationUser,
+		"password":        n.config.MySQL.ReplicationPassword,
 		"ssl":             useSsl,
-		"sslCa":           n.Config.MySQL.ReplicationSslCA,
-		"retryCount":      n.Config.MySQL.ReplicationRetryCount,
-		"connectRetry":    n.Config.MySQL.ReplicationConnectRetry,
-		"heartbeatPeriod": n.Config.MySQL.ReplicationHeartbeatPeriod,
-		"channel":         n.Config.ReplicationChannel,
+		"sslCa":           n.config.MySQL.ReplicationSslCA,
+		"retryCount":      n.config.MySQL.ReplicationRetryCount,
+		"connectRetry":    n.config.MySQL.ReplicationConnectRetry,
+		"heartbeatPeriod": n.config.MySQL.ReplicationHeartbeatPeriod,
+		"channel":         n.config.ReplicationChannel,
 	})
 }
 
@@ -878,7 +878,7 @@ func (n *Node) GetStartupTime() (time.Time, error) {
 
 // GetReplicaStatus returns slave/replica status or nil if node is master
 func (n *Node) GetReplicaStatus() (ReplicaStatus, error) {
-	return n.ReplicaStatusWithTimeout(n.Config.DBTimeout, n.Config.ReplicationChannel)
+	return n.ReplicaStatusWithTimeout(n.config.DBTimeout, n.config.ReplicationChannel)
 }
 
 func (n *Node) UpdateExternalCAFile() error {
@@ -888,7 +888,7 @@ func (n *Node) UpdateExternalCAFile() error {
 		return nil
 	}
 	data := replSettings.SourceSslCa
-	fileName := n.Config.MySQL.ExternalReplicationSslCA
+	fileName := n.config.MySQL.ExternalReplicationSslCA
 	if data != "" && fileName != "" {
 		err = util.TouchFile(fileName)
 		if err != nil {
diff --git a/internal/mysql/replication.go b/internal/mysql/replication.go
index 52185a0c..c7fe48a7 100644
--- a/internal/mysql/replication.go
+++ b/internal/mysql/replication.go
@@ -52,8 +52,9 @@ func NewExternalReplication(replicationType util.ExternalReplicationType, logger
 		return &ExternalReplication{
 			logger: logger,
 		}, nil
+	default:
+		return &UnimplementedExternalReplication{}, nil
 	}
-	return &UnimplementedExternalReplication{}, nil
 }
 
 // GetExternalReplicaStatus returns slave/replica status or nil if node is master for external channel
@@ -66,7 +67,7 @@ func (er *ExternalReplication) GetReplicaStatus(n *Node) (ReplicaStatus, error)
 		return nil, nil
 	}
 
-	return n.ReplicaStatusWithTimeout(n.Config.DBTimeout, n.Config.ExternalReplicationChannel)
+	return n.ReplicaStatusWithTimeout(n.config.DBTimeout, n.config.ExternalReplicationChannel)
 }
 
 // StartExternalReplication starts external replication
@@ -77,7 +78,7 @@ func (er *ExternalReplication) Start(n *Node) error {
 	}
 	if checked {
 		err := n.ExecMogrify(queryStartReplica, map[string]interface{}{
-			"channel": n.Config.ExternalReplicationChannel,
+			"channel": n.config.ExternalReplicationChannel,
 		})
 		if err != nil {
 			return err
@@ -94,7 +95,7 @@ func (er *ExternalReplication) Stop(n *Node) error {
 	}
 	if checked {
 		err := n.ExecMogrify(queryStopReplica, map[string]interface{}{
-			"channel": n.Config.ExternalReplicationChannel,
+			"channel": n.config.ExternalReplicationChannel,
 		})
 		if err != nil && !IsErrorChannelDoesNotExists(err) {
 			return err
@@ -111,7 +112,7 @@ func (er *ExternalReplication) Reset(n *Node) error {
 	}
 	if checked {
 		err := n.ExecMogrify(queryResetReplicaAll, map[string]interface{}{
-			"channel": n.Config.ExternalReplicationChannel,
+			"channel": n.config.ExternalReplicationChannel,
 		})
 		if err != nil && !IsErrorChannelDoesNotExists(err) {
 			return err
@@ -145,9 +146,9 @@ func (er *ExternalReplication) Set(n *Node) error {
 	}
 	useSsl := 0
 	sslCa := ""
-	if replSettings.SourceSslCa != "" && n.Config.MySQL.ExternalReplicationSslCA != "" {
+	if replSettings.SourceSslCa != "" && n.config.MySQL.ExternalReplicationSslCA != "" {
 		useSsl = 1
-		sslCa = n.Config.MySQL.ExternalReplicationSslCA
+		sslCa = n.config.MySQL.ExternalReplicationSslCA
 	}
 	err = er.Stop(n)
 	if err != nil {
@@ -165,9 +166,9 @@ func (er *ExternalReplication) Set(n *Node) error {
 		"ssl":             useSsl,
 		"sslCa":           sslCa,
 		"sourceDelay":     replSettings.SourceDelay,
-		"retryCount":      n.Config.MySQL.ReplicationRetryCount,
-		"connectRetry":    n.Config.MySQL.ReplicationConnectRetry,
-		"heartbeatPeriod": n.Config.MySQL.ReplicationHeartbeatPeriod,
+		"retryCount":      n.config.MySQL.ReplicationRetryCount,
+		"connectRetry":    n.config.MySQL.ReplicationConnectRetry,
+		"heartbeatPeriod": n.config.MySQL.ReplicationHeartbeatPeriod,
 		"channel":         "external",
 	})
 	if err != nil {