diff --git a/internal/flypg/pg.go b/internal/flypg/pg.go
index 90557324..074c7ddd 100644
--- a/internal/flypg/pg.go
+++ b/internal/flypg/pg.go
@@ -249,7 +249,7 @@ func (c *PGConfig) initialize() error {
 }
 
 func (c *PGConfig) writePGConfigEntries(entries []string) error {
-	file, err := os.Create(c.configFilePath)
+	file, err := os.OpenFile(c.configFilePath, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
 	if err != nil {
 		return err
 	}
diff --git a/internal/flypg/repmgr.go b/internal/flypg/repmgr.go
index 6fa152a2..b2157fdb 100644
--- a/internal/flypg/repmgr.go
+++ b/internal/flypg/repmgr.go
@@ -124,7 +124,7 @@ func (r *RepMgr) initialize() error {
 		return fmt.Errorf("failed to set repmgr.conf ownership: %s", err)
 	}
 
-	return file.Sync()
+	return nil
 }
 
 func (r *RepMgr) setup(ctx context.Context, conn *pgx.Conn) error {
@@ -236,7 +236,7 @@ func (r *RepMgr) clonePrimary(ipStr string) error {
 
 func (r *RepMgr) writePasswdConf() error {
 	path := "/data/.pgpass"
-	file, err := os.Create(path)
+	file, err := os.OpenFile(path, os.O_CREATE|os.O_RDWR|os.O_TRUNC, 0600)
 	if err != nil {
 		return fmt.Errorf("failed to open repmgr password file: %s", err)
 	}
diff --git a/internal/flypg/restore.go b/internal/flypg/restore.go
index 8f3f4a0e..f0b373b0 100644
--- a/internal/flypg/restore.go
+++ b/internal/flypg/restore.go
@@ -160,7 +160,7 @@ func restoreHBAFile() error {
 }
 
 func setRestoreLock() error {
-	file, err := os.Create(restoreLockFile)
+	file, err := os.OpenFile(restoreLockFile, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
 	if err != nil {
 		return err
 	}