Azure: Ignore NTFS mount errors when checking ephemeral drive

The Azure data source provides a method to check whether a NTFS partition
on the ephemeral disk is safe for reformatting to ext4. The method checks
to see if there are customer data files on the disk. However, mounting
the partition fails on systems that do not have the capability of
mounting NTFS. Note that in this case, it is also very unlikely that the
NTFS partition would have been used by the system (since it can't mount
it). The only case would be where an update to the system removed the
capability to mount NTFS, the likelihood of which is also very small.
This change allows the reformatting of the ephemeral disk to ext4 on
systems where mounting NTFS is not supported.

1 files changed, 88 insertions, 17 deletions

diff --git a/tests/unittests/test_datasource/test_azure.py b/tests/unittests/test_datasource/test_azure.py
index 26e8d7d3..e82716eb 100644
--- a/tests/unittests/test_datasource/test_azure.py
+++ b/tests/unittests/test_datasource/test_azure.py
@@ -1,10 +1,10 @@
 # This file is part of cloud-init. See LICENSE file for license information.
 
 from cloudinit import helpers
-from cloudinit.util import b64e, decode_binary, load_file, write_file
 from cloudinit.sources import DataSourceAzure as dsaz
-from cloudinit.util import find_freebsd_part
-from cloudinit.util import get_path_dev_freebsd
+from cloudinit.util import (b64e, decode_binary, load_file, write_file,
+                            find_freebsd_part, get_path_dev_freebsd,
+                            MountFailedError)
 from cloudinit.version import version_string as vs
 from cloudinit.tests.helpers import (CiTestCase, TestCase, populate_dir, mock,
                                      ExitStack, PY26, SkipTest)
@@ -95,6 +95,8 @@ class TestAzureDataSource(CiTestCase):
         self.patches = ExitStack()
         self.addCleanup(self.patches.close)
 
+        self.patches.enter_context(mock.patch.object(dsaz, '_get_random_seed'))
+
         super(TestAzureDataSource, self).setUp()
 
     def apply_patches(self, patches):
@@ -335,6 +337,18 @@ fdescfs            /dev/fd          fdescfs rw              0 0
         self.assertTrue(ret)
         self.assertEqual(data['agent_invoked'], '_COMMAND')
 
+    def test_sys_cfg_set_never_destroy_ntfs(self):
+        sys_cfg = {'datasource': {'Azure': {
+            'never_destroy_ntfs': 'user-supplied-value'}}}
+        data = {'ovfcontent': construct_valid_ovf_env(data={}),
+                'sys_cfg': sys_cfg}
+
+        dsrc = self._get_ds(data)
+        ret = self._get_and_setup(dsrc)
+        self.assertTrue(ret)
+        self.assertEqual(dsrc.ds_cfg.get(dsaz.DS_CFG_KEY_PRESERVE_NTFS),
+                         'user-supplied-value')
+
     def test_username_used(self):
         odata = {'HostName': "myhost", 'UserName': "myuser"}
         data = {'ovfcontent': construct_valid_ovf_env(data=odata)}
@@ -676,6 +690,8 @@ class TestAzureBounce(CiTestCase):
                               mock.MagicMock(return_value={})))
         self.patches.enter_context(
             mock.patch.object(dsaz.util, 'which', lambda x: True))
+        self.patches.enter_context(
+            mock.patch.object(dsaz, '_get_random_seed'))
 
         def _dmi_mocks(key):
             if key == 'system-uuid':
@@ -957,7 +973,9 @@ class TestCanDevBeReformatted(CiTestCase):
             # return sorted by partition number
             return sorted(ret, key=lambda d: d[0])
 
-        def mount_cb(device, callback):
+        def mount_cb(device, callback, mtype, update_env_for_mount):
+            self.assertEqual('ntfs', mtype)
+            self.assertEqual('C', update_env_for_mount.get('LANG'))
             p = self.tmp_dir()
             for f in bypath.get(device).get('files', []):
                 write_file(os.path.join(p, f), content=f)
@@ -988,14 +1006,16 @@ class TestCanDevBeReformatted(CiTestCase):
                     '/dev/sda2': {'num': 2},
                     '/dev/sda3': {'num': 3},
                 }}})
-        value, msg = dsaz.can_dev_be_reformatted("/dev/sda")
+        value, msg = dsaz.can_dev_be_reformatted("/dev/sda",
+                                                 preserve_ntfs=False)
         self.assertFalse(value)
         self.assertIn("3 or more", msg.lower())
 
     def test_no_partitions_is_false(self):
         """A disk with no partitions can not be formatted."""
         self.patchup({'/dev/sda': {}})
-        value, msg = dsaz.can_dev_be_reformatted("/dev/sda")
+        value, msg = dsaz.can_dev_be_reformatted("/dev/sda",
+                                                 preserve_ntfs=False)
         self.assertFalse(value)
         self.assertIn("not partitioned", msg.lower())
 
@@ -1007,7 +1027,8 @@ class TestCanDevBeReformatted(CiTestCase):
                     '/dev/sda1': {'num': 1},
                     '/dev/sda2': {'num': 2, 'fs': 'ext4', 'files': []},
                 }}})
-        value, msg = dsaz.can_dev_be_reformatted("/dev/sda")
+        value, msg = dsaz.can_dev_be_reformatted("/dev/sda",
+                                                 preserve_ntfs=False)
         self.assertFalse(value)
         self.assertIn("not ntfs", msg.lower())
 
@@ -1020,7 +1041,8 @@ class TestCanDevBeReformatted(CiTestCase):
                     '/dev/sda2': {'num': 2, 'fs': 'ntfs',
                                   'files': ['secret.txt']},
                 }}})
-        value, msg = dsaz.can_dev_be_reformatted("/dev/sda")
+        value, msg = dsaz.can_dev_be_reformatted("/dev/sda",
+                                                 preserve_ntfs=False)
         self.assertFalse(value)
         self.assertIn("files on it", msg.lower())
 
@@ -1032,7 +1054,8 @@ class TestCanDevBeReformatted(CiTestCase):
                     '/dev/sda1': {'num': 1},
                     '/dev/sda2': {'num': 2, 'fs': 'ntfs', 'files': []},
                 }}})
-        value, msg = dsaz.can_dev_be_reformatted("/dev/sda")
+        value, msg = dsaz.can_dev_be_reformatted("/dev/sda",
+                                                 preserve_ntfs=False)
         self.assertTrue(value)
         self.assertIn("safe for", msg.lower())
 
@@ -1043,7 +1066,8 @@ class TestCanDevBeReformatted(CiTestCase):
                 'partitions': {
                     '/dev/sda1': {'num': 1, 'fs': 'zfs'},
                 }}})
-        value, msg = dsaz.can_dev_be_reformatted("/dev/sda")
+        value, msg = dsaz.can_dev_be_reformatted("/dev/sda",
+                                                 preserve_ntfs=False)
         self.assertFalse(value)
         self.assertIn("not ntfs", msg.lower())
 
@@ -1055,9 +1079,14 @@ class TestCanDevBeReformatted(CiTestCase):
                     '/dev/sda1': {'num': 1, 'fs': 'ntfs',
                                   'files': ['file1.txt', 'file2.exe']},
                 }}})
-        value, msg = dsaz.can_dev_be_reformatted("/dev/sda")
-        self.assertFalse(value)
-        self.assertIn("files on it", msg.lower())
+        with mock.patch.object(dsaz.LOG, 'warning') as warning:
+            value, msg = dsaz.can_dev_be_reformatted("/dev/sda",
+                                                     preserve_ntfs=False)
+            wmsg = warning.call_args[0][0]
+            self.assertIn("looks like you're using NTFS on the ephemeral disk",
+                          wmsg)
+            self.assertFalse(value)
+            self.assertIn("files on it", msg.lower())
 
     def test_one_partition_ntfs_empty_is_true(self):
         """1 mountable ntfs partition and no files can be formatted."""
@@ -1066,7 +1095,8 @@ class TestCanDevBeReformatted(CiTestCase):
                 'partitions': {
                     '/dev/sda1': {'num': 1, 'fs': 'ntfs', 'files': []}
                 }}})
-        value, msg = dsaz.can_dev_be_reformatted("/dev/sda")
+        value, msg = dsaz.can_dev_be_reformatted("/dev/sda",
+                                                 preserve_ntfs=False)
         self.assertTrue(value)
         self.assertIn("safe for", msg.lower())
 
@@ -1078,7 +1108,8 @@ class TestCanDevBeReformatted(CiTestCase):
                     '/dev/sda1': {'num': 1, 'fs': 'ntfs',
                                   'files': ['dataloss_warning_readme.txt']}
                 }}})
-        value, msg = dsaz.can_dev_be_reformatted("/dev/sda")
+        value, msg = dsaz.can_dev_be_reformatted("/dev/sda",
+                                                 preserve_ntfs=False)
         self.assertTrue(value)
         self.assertIn("safe for", msg.lower())
 
@@ -1093,7 +1124,8 @@ class TestCanDevBeReformatted(CiTestCase):
                         'num': 1, 'fs': 'ntfs', 'files': [self.warning_file],
                         'realpath': '/dev/sdb1'}
                 }}})
-        value, msg = dsaz.can_dev_be_reformatted(epath)
+        value, msg = dsaz.can_dev_be_reformatted(epath,
+                                                 preserve_ntfs=False)
         self.assertTrue(value)
         self.assertIn("safe for", msg.lower())
 
@@ -1112,10 +1144,49 @@ class TestCanDevBeReformatted(CiTestCase):
                     epath + '-part3': {'num': 3, 'fs': 'ext',
                                        'realpath': '/dev/sdb3'}
                 }}})
-        value, msg = dsaz.can_dev_be_reformatted(epath)
+        value, msg = dsaz.can_dev_be_reformatted(epath,
+                                                 preserve_ntfs=False)
         self.assertFalse(value)
         self.assertIn("3 or more", msg.lower())
 
+    def test_ntfs_mount_errors_true(self):
+        """can_dev_be_reformatted does not fail if NTFS is unknown fstype."""
+        self.patchup({
+            '/dev/sda': {
+                'partitions': {
+                    '/dev/sda1': {'num': 1, 'fs': 'ntfs', 'files': []}
+                }}})
+
+        err = ("Unexpected error while running command.\n",
+               "Command: ['mount', '-o', 'ro,sync', '-t', 'auto', ",
+               "'/dev/sda1', '/fake-tmp/dir']\n"
+               "Exit code: 32\n"
+               "Reason: -\n"
+               "Stdout: -\n"
+               "Stderr: mount: unknown filesystem type 'ntfs'")
+        self.m_mount_cb.side_effect = MountFailedError(
+            'Failed mounting %s to %s due to: %s' %
+            ('/dev/sda', '/fake-tmp/dir', err))
+
+        value, msg = dsaz.can_dev_be_reformatted('/dev/sda',
+                                                 preserve_ntfs=False)
+        self.assertTrue(value)
+        self.assertIn('cannot mount NTFS, assuming', msg)
+
+    def test_never_destroy_ntfs_config_false(self):
+        """Normally formattable situation with never_destroy_ntfs set."""
+        self.patchup({
+            '/dev/sda': {
+                'partitions': {
+                    '/dev/sda1': {'num': 1, 'fs': 'ntfs',
+                                  'files': ['dataloss_warning_readme.txt']}
+                }}})
+        value, msg = dsaz.can_dev_be_reformatted("/dev/sda",
+                                                 preserve_ntfs=True)
+        self.assertFalse(value)
+        self.assertIn("config says to never destroy NTFS "
+                      "(datasource.Azure.never_destroy_ntfs)", msg)
+
 
 class TestAzureNetExists(CiTestCase):