libvirt: Add option to ssh to prevent prompting

When doing migration with libvirt driver there are
ssh commands that can cause prompting if ssh
is not configured correctly.
This patch disables the prompting by adding
BatchMode=yes option to the ssh command.

Closes-Bug: #1437790

Change-Id: Ib1e38f397afaac96a2e1a8717c87a4b6756419db

nova/tests/unit/test_utils.py

@@ -218,6 +218,13 @@ class GenericUtilsTestCase(test.NoDBTestCase):
         cmd = utils._get_root_helper()
         self.assertEqual('sudo', cmd)
 
+    def test_ssh_execute(self):
+        expected_args = ('ssh', '-o', 'BatchMode=yes',
+                         'remotehost', 'ls', '-l')
+        with mock.patch('nova.utils.execute') as mock_method:
+            utils.ssh_execute('remotehost', 'ls', '-l')
+        mock_method.assert_called_once_with(*expected_args)
+
 
 class VPNPingTestCase(test.NoDBTestCase):
     """Unit tests for utils.vpn_ping()."""

nova/tests/unit/virt/libvirt/test_driver.py

@@ -9703,21 +9703,22 @@ Active:          8381604 kB
         drvr._set_cache_mode(fake_conf)
         self.assertEqual(fake_conf.driver_cache, 'fake')
 
-    def _test_shared_storage_detection(self, is_same):
+    @mock.patch('os.unlink')
+    @mock.patch.object(os.path, 'exists')
+    def _test_shared_storage_detection(self, is_same,
+                                       mock_exists, mock_unlink):
         drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
-        self.mox.StubOutWithMock(drvr, 'get_host_ip_addr')
-        self.mox.StubOutWithMock(utils, 'execute')
-        self.mox.StubOutWithMock(os.path, 'exists')
-        self.mox.StubOutWithMock(os, 'unlink')
-        drvr.get_host_ip_addr().AndReturn('bar')
-        utils.execute('ssh', 'foo', 'touch', mox.IgnoreArg())
-        os.path.exists(mox.IgnoreArg()).AndReturn(is_same)
+        drvr.get_host_ip_addr = mock.MagicMock(return_value='bar')
+        mock_exists.return_value = is_same
+        with mock.patch('nova.utils.ssh_execute') as mock_ssh_method:
+            result = drvr._is_storage_shared_with('foo', '/path')
+        mock_ssh_method.assert_any_call('foo', 'touch', mock.ANY)
         if is_same:
-            os.unlink(mox.IgnoreArg())
+            mock_unlink.assert_called_once_with(mock.ANY)
         else:
-            utils.execute('ssh', 'foo', 'rm', mox.IgnoreArg())
-        self.mox.ReplayAll()
-        return drvr._is_storage_shared_with('foo', '/path')
+            self.assertEqual(2, mock_ssh_method.call_count)
+            mock_ssh_method.assert_called_with('foo', 'rm', mock.ANY)
+        return result
 
     def test_shared_storage_detection_same_host(self):
         self.assertTrue(self._test_shared_storage_detection(True))

nova/utils.py

@@ -206,6 +206,14 @@ def execute(*cmd, **kwargs):
     return processutils.execute(*cmd, **kwargs)
 
 
+def ssh_execute(dest, *cmd, **kwargs):
+    """Convenience wrapper to execute ssh command."""
+    ssh_cmd = ['ssh', '-o', 'BatchMode=yes']
+    ssh_cmd.append(dest)
+    ssh_cmd.extend(cmd)
+    return execute(*ssh_cmd, **kwargs)
+
+
 def trycmd(*args, **kwargs):
     """Convenience wrapper around oslo's trycmd() method."""
     if 'run_as_root' in kwargs and 'root_helper' not in kwargs:

nova/virt/libvirt/driver.py

@@ -6127,7 +6127,7 @@ class LibvirtDriver(driver.ComputeDriver):
                 utils.execute('rm', '-rf', inst_base)
                 utils.execute('mv', inst_base_resize, inst_base)
                 if not shared_storage:
-                    utils.execute('ssh', dest, 'rm', '-rf', inst_base)
+                    utils.ssh_execute(dest, 'rm', '-rf', inst_base)
         except Exception:
             pass
 
@@ -6142,12 +6142,12 @@ class LibvirtDriver(driver.ComputeDriver):
             tmp_path = os.path.join(inst_base, tmp_file)
 
             try:
-                utils.execute('ssh', dest, 'touch', tmp_path)
+                utils.ssh_execute(dest, 'touch', tmp_path)
                 if os.path.exists(tmp_path):
                     shared_storage = True
                     os.unlink(tmp_path)
                 else:
-                    utils.execute('ssh', dest, 'rm', tmp_path)
+                    utils.ssh_execute(dest, 'rm', tmp_path)
             except Exception:
                 pass
         return shared_storage
@@ -6199,7 +6199,7 @@ class LibvirtDriver(driver.ComputeDriver):
         # failures here earlier
         if not shared_storage:
             try:
-                utils.execute('ssh', dest, 'mkdir', '-p', inst_base)
+                utils.ssh_execute(dest, 'mkdir', '-p', inst_base)
             except processutils.ProcessExecutionError as e:
                 reason = _("not able to execute ssh command: %s") % e
                 raise exception.InstanceFaultRollback(