From 129b1c4ea250619bd7caed7aaffacc796b0139f2 Mon Sep 17 00:00:00 2001 From: AOhassan <37305877+AOhassan@users.noreply.github.com> Date: Thu, 12 Dec 2019 13:51:42 -0800 Subject: 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. --- cloudinit/sources/DataSourceAzure.py | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'cloudinit/sources/DataSourceAzure.py') 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: -- cgit v1.2.3