diff --git a/uncloud/vmm/__init__.py b/uncloud/vmm/__init__.py
index 719bdbe..6db61eb 100644
--- a/uncloud/vmm/__init__.py
+++ b/uncloud/vmm/__init__.py
@@ -125,7 +125,7 @@ class VMM:
             os.makedirs(self.socket_dir, exist_ok=True)
 
     def is_running(self, uuid):
-        sock_path = os.path.join(self.vmm_backend, uuid)
+        sock_path = os.path.join(self.socket_dir, uuid)
         try:
             sock = socket.socket(socket.AF_UNIX)
             sock.connect(sock_path)
@@ -163,7 +163,7 @@ class VMM:
             qmp_arg = (
                 "-qmp",
                 "unix:{},server,nowait".format(
-                    join_path(self.vmm_backend, uuid)
+                    join_path(self.socket_dir, uuid)
                 ),
             )
             vnc_arg = (
@@ -212,7 +212,7 @@ class VMM:
     def execute_command(self, uuid, command, **kwargs):
         # execute_command -> sucess?, output
         try:
-            with VMQMPHandles(os.path.join(self.vmm_backend, uuid)) as (
+            with VMQMPHandles(os.path.join(self.socket_dir, uuid)) as (
                 sock_handle,
                 file_handle,
             ):
@@ -255,8 +255,8 @@ class VMM:
     def discover(self):
         vms = [
             uuid
-            for uuid in os.listdir(self.vmm_backend)
-            if not isdir(join_path(self.vmm_backend, uuid))
+            for uuid in os.listdir(self.socket_dir)
+            if not isdir(join_path(self.socket_dir, uuid))
         ]
         return vms