diff options
author | AOhassan <37305877+AOhassan@users.noreply.github.com> | 2019-12-12 13:51:42 -0800 |
---|---|---|
committer | Chad Smith <chad.smith@canonical.com> | 2019-12-12 14:51:42 -0700 |
commit | 129b1c4ea250619bd7caed7aaffacc796b0139f2 (patch) | |
tree | 96970dbb7ef64d5f1399659dbf4a5f46519f81ef | |
parent | e2840f1771158748780a768f6bfbb117cd7610c6 (diff) | |
download | vyos-cloud-init-129b1c4ea250619bd7caed7aaffacc796b0139f2.tar.gz vyos-cloud-init-129b1c4ea250619bd7caed7aaffacc796b0139f2.zip |
azure: avoid re-running cloud-init when instance-id is byte-swapped (#84)
Azure stores the instance ID with an incorrect byte ordering for the
first three hyphen delimited parts. This results in invalid
is_new_instance checks forcing Azure datasource to recrawl the metadata
service.
When persisting instance-id from the metadata service, swap the
instance-id string byte order such that it is consistent with
that returned by dmi information. Check whether the instance-id
string is a byte-swapped match when determining correctly whether
the Azure platform instance-id has actually changed.
-rwxr-xr-x | cloudinit/sources/DataSourceAzure.py | 16 | ||||
-rwxr-xr-x | cloudinit/sources/helpers/azure.py | 27 | ||||
-rw-r--r-- | tests/unittests/test_datasource/test_azure.py | 24 | ||||
-rw-r--r-- | tests/unittests/test_datasource/test_azure_helper.py | 19 |
4 files changed, 80 insertions, 6 deletions
diff --git a/cloudinit/sources/DataSourceAzure.py b/cloudinit/sources/DataSourceAzure.py index 87a848ce..24f448c5 100755 --- a/cloudinit/sources/DataSourceAzure.py +++ b/cloudinit/sources/DataSourceAzure.py @@ -33,7 +33,8 @@ from cloudinit.sources.helpers.azure import ( get_boot_telemetry, get_system_info, report_diagnostic_event, - EphemeralDHCPv4WithReporting) + EphemeralDHCPv4WithReporting, + is_byte_swapped) LOG = logging.getLogger(__name__) @@ -471,8 +472,7 @@ class DataSourceAzure(sources.DataSource): seed = _get_random_seed() if seed: crawled_data['metadata']['random_seed'] = seed - crawled_data['metadata']['instance-id'] = util.read_dmi_data( - 'system-uuid') + crawled_data['metadata']['instance-id'] = self._iid() if perform_reprovision: LOG.info("Reporting ready to Azure after getting ReprovisionData") @@ -558,6 +558,16 @@ class DataSourceAzure(sources.DataSource): # quickly (local check only) if self.instance_id is still valid return sources.instance_id_matches_system_uuid(self.get_instance_id()) + def _iid(self, previous=None): + prev_iid_path = os.path.join( + self.paths.get_cpath('data'), 'instance-id') + iid = util.read_dmi_data('system-uuid') + if os.path.exists(prev_iid_path): + previous = util.load_file(prev_iid_path).strip() + if is_byte_swapped(previous, iid): + return previous + return iid + @azure_ds_telemetry_reporter def setup(self, is_new_instance): if self._negotiated is False: diff --git a/cloudinit/sources/helpers/azure.py b/cloudinit/sources/helpers/azure.py index f5cdb3fd..fc760581 100755 --- a/cloudinit/sources/helpers/azure.py +++ b/cloudinit/sources/helpers/azure.py @@ -7,6 +7,7 @@ import re import socket import struct import time +import textwrap from cloudinit.net import dhcp from cloudinit import stages @@ -48,6 +49,32 @@ def azure_ds_telemetry_reporter(func): return impl +def is_byte_swapped(previous_id, current_id): + """ + Azure stores the instance ID with an incorrect byte ordering for the + first parts. This corrects the byte order such that it is consistent with + that returned by the metadata service. + """ + if previous_id == current_id: + return False + + def swap_bytestring(s, width=2): + dd = [byte for byte in textwrap.wrap(s, 2)] + dd.reverse() + return ''.join(dd) + + parts = current_id.split('-') + swapped_id = '-'.join([ + swap_bytestring(parts[0]), + swap_bytestring(parts[1]), + swap_bytestring(parts[2]), + parts[3], + parts[4] + ]) + + return previous_id == swapped_id + + @azure_ds_telemetry_reporter def get_boot_telemetry(): """Report timestamps related to kernel initialization and systemd diff --git a/tests/unittests/test_datasource/test_azure.py b/tests/unittests/test_datasource/test_azure.py index 59e351de..a809fd87 100644 --- a/tests/unittests/test_datasource/test_azure.py +++ b/tests/unittests/test_datasource/test_azure.py @@ -477,7 +477,7 @@ scbus-1 on xpt0 bus 0 'public-keys': [], }) - self.instance_id = 'test-instance-id' + self.instance_id = 'D0DF4C54-4ECB-4A4B-9954-5BDF3ED5C3B8' def _dmi_mocks(key): if key == 'system-uuid': @@ -645,7 +645,7 @@ scbus-1 on xpt0 bus 0 'azure_data': { 'configurationsettype': 'LinuxProvisioningConfiguration'}, 'imds': NETWORK_METADATA, - 'instance-id': 'test-instance-id', + 'instance-id': 'D0DF4C54-4ECB-4A4B-9954-5BDF3ED5C3B8', 'local-hostname': u'myhost', 'random_seed': 'wild'} @@ -1091,6 +1091,24 @@ scbus-1 on xpt0 bus 0 self.assertTrue(ret) self.assertEqual('value', dsrc.metadata['test']) + def test_instance_id_endianness(self): + """Return the previous iid when dmi uuid is the byteswapped iid.""" + ds = self._get_ds({'ovfcontent': construct_valid_ovf_env()}) + # byte-swapped previous + write_file( + os.path.join(self.paths.cloud_dir, 'data', 'instance-id'), + '544CDFD0-CB4E-4B4A-9954-5BDF3ED5C3B8') + ds.get_data() + self.assertEqual( + '544CDFD0-CB4E-4B4A-9954-5BDF3ED5C3B8', ds.metadata['instance-id']) + # not byte-swapped previous + write_file( + os.path.join(self.paths.cloud_dir, 'data', 'instance-id'), + '644CDFD0-CB4E-4B4A-9954-5BDF3ED5C3B8') + ds.get_data() + self.assertEqual( + 'D0DF4C54-4ECB-4A4B-9954-5BDF3ED5C3B8', ds.metadata['instance-id']) + def test_instance_id_from_dmidecode_used(self): ds = self._get_ds({'ovfcontent': construct_valid_ovf_env()}) ds.get_data() @@ -1292,7 +1310,7 @@ class TestAzureBounce(CiTestCase): def _dmi_mocks(key): if key == 'system-uuid': - return 'test-instance-id' + return 'D0DF4C54-4ECB-4A4B-9954-5BDF3ED5C3B8' elif key == 'chassis-asset-tag': return '7783-7084-3265-9085-8269-3286-77' raise RuntimeError('should not get here') diff --git a/tests/unittests/test_datasource/test_azure_helper.py b/tests/unittests/test_datasource/test_azure_helper.py index bd17f636..007df09f 100644 --- a/tests/unittests/test_datasource/test_azure_helper.py +++ b/tests/unittests/test_datasource/test_azure_helper.py @@ -170,6 +170,25 @@ class TestGoalStateParsing(CiTestCase): goal_state = self._get_goal_state(instance_id=instance_id) self.assertEqual(instance_id, goal_state.instance_id) + def test_instance_id_byte_swap(self): + """Return true when previous_iid is byteswapped current_iid""" + previous_iid = "D0DF4C54-4ECB-4A4B-9954-5BDF3ED5C3B8" + current_iid = "544CDFD0-CB4E-4B4A-9954-5BDF3ED5C3B8" + self.assertTrue( + azure_helper.is_byte_swapped(previous_iid, current_iid)) + + def test_instance_id_no_byte_swap_same_instance_id(self): + previous_iid = "D0DF4C54-4ECB-4A4B-9954-5BDF3ED5C3B8" + current_iid = "D0DF4C54-4ECB-4A4B-9954-5BDF3ED5C3B8" + self.assertFalse( + azure_helper.is_byte_swapped(previous_iid, current_iid)) + + def test_instance_id_no_byte_swap_diff_instance_id(self): + previous_iid = "D0DF4C54-4ECB-4A4B-9954-5BDF3ED5C3B8" + current_iid = "G0DF4C54-4ECB-4A4B-9954-5BDF3ED5C3B8" + self.assertFalse( + azure_helper.is_byte_swapped(previous_iid, current_iid)) + def test_certificates_xml_parsed_and_fetched_correctly(self): http_client = mock.MagicMock() certificates_url = 'TestCertificatesUrl' |