From 29e938dc74bfea7edd0c69963efe25ec844527cb Mon Sep 17 00:00:00 2001
From: meow <ahmedbilal96@gmail.com>
Date: Sun, 29 Dec 2019 23:48:04 +0500
Subject: [PATCH] Destination Host of VM during migration now notify Source
 host of exact socket path

---
 ucloud/common/request.py      |  1 +
 ucloud/host/main.py           |  3 ++-
 ucloud/host/virtualmachine.py |  6 ++++--
 ucloud/vmm/__init__.py        | 15 ++++++++++-----
 4 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/ucloud/common/request.py b/ucloud/common/request.py
index 2d9be44..5705eed 100644
--- a/ucloud/common/request.py
+++ b/ucloud/common/request.py
@@ -19,6 +19,7 @@ class RequestType:
 class RequestEntry(SpecificEtcdEntryBase):
 
     def __init__(self, e):
+        self.destination_sock_path = None
         self.destination_host_key = None
         self.type = None  # type: str
         self.migration = None  # type: bool
diff --git a/ucloud/host/main.py b/ucloud/host/main.py
index b5aeee3..904f26c 100755
--- a/ucloud/host/main.py
+++ b/ucloud/host/main.py
@@ -76,7 +76,8 @@ def main(hostname):
                     elif request_event.type == RequestType.TransferVM:
                         host = host_pool.get(request_event.destination_host_key)
                         if host:
-                            vm.migrate(destination=host.hostname)
+                            vm.migrate(destination_host=host.hostname,
+                                       destination_sock_path=request_event.destination_sock_path)
                         else:
                             logger.error('Host %s not found!', request_event.destination_host_key)
                 else:
diff --git a/ucloud/host/virtualmachine.py b/ucloud/host/virtualmachine.py
index 6d25205..db0f7b8 100755
--- a/ucloud/host/virtualmachine.py
+++ b/ucloud/host/virtualmachine.py
@@ -78,6 +78,7 @@ class VM:
                     type=RequestType.TransferVM,  # Transfer VM
                     hostname=self.host_key,  # Which VM should get this request. It is source host
                     uuid=self.uuid,  # uuid of VM
+                    destination_sock_path=join_path(self.vmm.socket_dir, self.uuid),
                     destination_host_key=destination_host_key,  # Where source host transfer VM
                     request_prefix=settings['etcd']['request_prefix']
                 )
@@ -94,8 +95,9 @@ class VM:
         declare_stopped(self.vm)
         self.sync()
 
-    def migrate(self, destination):
-        self.vmm.transfer(src_uuid=self.uuid, dest_uuid=self.uuid, host=destination)
+    def migrate(self, destination_host, destination_sock_path):
+        self.vmm.transfer(src_uuid=self.uuid, destination_sock_path=destination_sock_path,
+                          host=destination_host)
 
     def create_network_dev(self):
         command = ''
diff --git a/ucloud/vmm/__init__.py b/ucloud/vmm/__init__.py
index f85d7a3..9f9f5f9 100644
--- a/ucloud/vmm/__init__.py
+++ b/ucloud/vmm/__init__.py
@@ -42,12 +42,11 @@ class VMQMPHandles:
 
 
 class TransferVM(Process):
-    def __init__(self, src_uuid, dest_uuid, host, socket_dir):
+    def __init__(self, src_uuid, dest_sock_path, host, socket_dir):
         self.src_uuid = src_uuid
-        self.dest_uuid = dest_uuid
         self.host = host
         self.src_sock_path = os.path.join(socket_dir, self.src_uuid)
-        self.dest_sock_path = os.path.join(socket_dir, self.dest_uuid)
+        self.dest_sock_path = dest_sock_path
 
         super().__init__()
 
@@ -203,6 +202,12 @@ class VMM:
             return output['return']['service']
         return None
 
-    def transfer(self, src_uuid, dest_uuid, host):
-        p = TransferVM(src_uuid, dest_uuid, socket_dir=self.socket_dir, host=host)
+    def transfer(self, src_uuid, destination_sock_path, host):
+        p = TransferVM(src_uuid, destination_sock_path, socket_dir=self.socket_dir, host=host)
         p.start()
+
+    # TODO: the following method should clean things that went wrong
+    #       e.g If VM migration fails or didn't start for long time
+    #       i.e 15 minutes we should stop the waiting VM.
+    def maintenace(self):
+        pass
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