Merge pull request firecracker-microvm#502 from alakesh/describe-instance

Fix for StopVM to force shutdown VM is in paused state in order to avoid hang

Author: alakesh

runtime/service.go

@@ -636,7 +636,8 @@ func (s *service) mountDrives(requestCtx context.Context) error {
 
 // StopVM will shutdown the VMM. Unlike Shutdown, this method is exposed to containerd clients.
 // If the VM has not been created yet and the timeout is hit waiting for it to exist, an error will be returned
-// but the shim will continue to shutdown.
+// but the shim will continue to shutdown. Similarly if we detect that the VM is in pause state, then
+// we are unable to communicate to the in-VM agent. In this case, we do a forceful shutdown.
 func (s *service) StopVM(requestCtx context.Context, request *proto.StopVMRequest) (_ *empty.Empty, err error) {
 	defer logPanicAndDie(s.logger)
 	s.logger.WithFields(logrus.Fields{"timeout_seconds": request.TimeoutSeconds}).Debug("StopVM")
@@ -646,6 +647,20 @@ func (s *service) StopVM(requestCtx context.Context, request *proto.StopVMReques
 		timeout = time.Duration(request.TimeoutSeconds) * time.Second
 	}
 
+	info, err := s.machine.DescribeInstanceInfo(requestCtx)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to get instance info %v", info)
+	}
+
+	if *info.State == models.InstanceInfoStatePaused {
+		s.logger.Debug("Instance is in Paused state, force shutdown in progress")
+		err = s.jailer.Stop(true)
+		if err != nil {
+			return nil, errors.Wrap(err, "failed to stop VM in paused State")
+		}
+		return &empty.Empty{}, nil
+	}
+
 	err = s.waitVMReady()
 	if err != nil {
 		return nil, err

runtime/service_integ_test.go

@@ -1537,6 +1537,7 @@ func TestStopVM_Isolated(t *testing.T) {
 		stopFunc        func(ctx context.Context, fcClient fccontrol.FirecrackerService, req proto.CreateVMRequest)
 		withStopVM      bool
 	}{
+
 		{
 			name:       "Successful",
 			withStopVM: true,
@@ -1626,6 +1627,22 @@ func TestStopVM_Isolated(t *testing.T) {
 				}
 			},
 		},
+
+		// Test that StopVM returns success if the VM is in paused state, instead of hanging forever.
+		// VM is force shutdown in this case, so we expect no Error or hang.
+		{
+			name:       "PauseStop",
+			withStopVM: true,
+
+			createVMRequest: proto.CreateVMRequest{},
+			stopFunc: func(ctx context.Context, fcClient fccontrol.FirecrackerService, req proto.CreateVMRequest) {
+				_, err = fcClient.PauseVM(ctx, &proto.PauseVMRequest{VMID: req.VMID})
+				require.Equal(status.Code(err), codes.OK)
+
+				_, err = fcClient.StopVM(ctx, &proto.StopVMRequest{VMID: req.VMID})
+				require.NoError(err)
+			},
+		},
 	}
 
 	fcClient, err := newFCControlClient(containerdSockPath)