[18.09 backport] Fix leaking task resources when nodes are deleted

manager/controlapi/node.go

@@ -254,25 +254,23 @@ func (s *Server) UpdateNode(ctx context.Context, request *api.UpdateNodeRequest)
 	}, nil
 }
 
-func removeNodeAttachments(tx store.Tx, nodeID string) error {
-	// orphan the node's attached containers. if we don't do this, the
-	// network these attachments are connected to will never be removeable
+func orphanNodeTasks(tx store.Tx, nodeID string) error {
+	// when a node is deleted, all of its tasks are irrecoverably removed.
+	// additionally, the Dispatcher can no longer be relied on to update the
+	// task status. Therefore, when the node is removed, we must additionally
+	// move all of its assigned tasks to the Orphaned state, so that their
+	// resources can be cleaned up.
 	tasks, err := store.FindTasks(tx, store.ByNodeID(nodeID))
 	if err != nil {
 		return err
 	}
 	for _, task := range tasks {
-		// if the task is an attachment, then we just delete it. the allocator
-		// will do the heavy lifting. basically, GetAttachment will return the
-		// attachment if that's the kind of runtime, or nil if it's not.
-		if task.Spec.GetAttachment() != nil {
-			// don't delete the task. instead, update it to `ORPHANED` so that
-			// the taskreaper will clean it up.
-			task.Status.State = api.TaskStateOrphaned
-			if err := store.UpdateTask(tx, task); err != nil {
-				return err
-			}
+		task.Status = api.TaskStatus{
+			Timestamp: gogotypes.TimestampNow(),
+			State:     api.TaskStateOrphaned,
+			Message:   "Task belonged to a node that has been deleted",
 		}
+		store.UpdateTask(tx, task)
 	}
 	return nil
 }
@@ -342,7 +340,7 @@ func (s *Server) RemoveNode(ctx context.Context, request *api.RemoveNodeRequest)
 			return err
 		}
 
-		if err := removeNodeAttachments(tx, request.NodeID); err != nil {
+		if err := orphanNodeTasks(tx, request.NodeID); err != nil {
 			return err
 		}
 

manager/controlapi/node_test.go

@@ -943,9 +943,7 @@ func TestUpdateNodeDemote(t *testing.T) {
 }
 
 // TestRemoveNodeAttachments tests the unexported removeNodeAttachments
-// function. This avoids us having to update the TestRemoveNodes function to
-// test all of this logic
-func TestRemoveNodeAttachments(t *testing.T) {
+func TestOrphanNodeTasks(t *testing.T) {
 	// first, set up a store and all that
 	ts := newTestServer(t)
 	defer ts.Stop()
@@ -1089,22 +1087,24 @@ func TestRemoveNodeAttachments(t *testing.T) {
 
 	// Now, call the function with our nodeID. make sure it returns no error
 	err = ts.Store.Update(func(tx store.Tx) error {
-		return removeNodeAttachments(tx, "id2")
+		return orphanNodeTasks(tx, "id2")
 	})
 	require.NoError(t, err)
 
-	// Now, make sure only task1, the network-attacahed task on id2, was
-	// removed
+	// Now, make sure only tasks 1 and 3, the tasks on the node we're deleting
+	// removed, are removed
 	ts.Store.View(func(tx store.ReadTx) {
 		tasks, err := store.FindTasks(tx, store.All)
 		require.NoError(t, err)
 		// should only be 3 tasks left
 		require.Len(t, tasks, 4)
-		// and the list should not contain task1
+		// and the list should not contain task1 or task2
 		for _, task := range tasks {
 			require.NotNil(t, task)
-			if task.ID == "task1" {
+			if task.ID == "task1" || task.ID == "task3" {
 				require.Equal(t, task.Status.State, api.TaskStateOrphaned)
+			} else {
+				require.NotEqual(t, task.Status.State, api.TaskStateOrphaned)
 			}
 		}
 	})