cloud-init-dev team mailing list archive

[Jason Zions <jason.zions@xxxxxxxxxxxxx>]

Jason Zions has proposed merging ~jasonzio/cloud-init:wireserverFallback into cloud-init:master.

Commit message:
Azure: Return static fallback address as if failed to find endpoint

The Azure data source helper attempts to use information in the dhcp
lease to find the Wireserver endpoint (IP address). Under some unusual
circumstances, those attempts will fail. This change uses a static
address, known to be always correct in the Azure public and sovereign
clouds, when the helper fails to locate a valid dhcp lease. This
address is not guaranteed to be correct in Azure Stack environments;
it's still best to use the information from the lease whenever possible.

Requested reviews:
  cloud-init commiters (cloud-init-dev)

For more details, see:
https://code.launchpad.net/~jasonzio/cloud-init/+git/cloud-init/+merge/367233
-- 
Your team cloud-init commiters is requested to review the proposed merge of ~jasonzio/cloud-init:wireserverFallback into cloud-init:master.

diff --git a/cloudinit/sources/helpers/azure.py b/cloudinit/sources/helpers/azure.py
index d3af05e..a5ca1e2 100755
--- a/cloudinit/sources/helpers/azure.py
+++ b/cloudinit/sources/helpers/azure.py
@@ -20,6 +20,7 @@ from cloudinit.reporting import events
 
 LOG = logging.getLogger(__name__)
 
+DEFAULT_WIRESERVER_ENDPOINT = "a8:3f:81:10"
 
 azure_ds_reporter = events.ReportEventStack(
     name="azure-ds",
@@ -297,7 +298,12 @@ class WALinuxAgentShim(object):
     @azure_ds_telemetry_reporter
     def _get_value_from_leases_file(fallback_lease_file):
         leases = []
-        content = util.load_file(fallback_lease_file)
+        try:
+            content = util.load_file(fallback_lease_file)
+        except Exception:
+            LOG.error("Exception while reading %s", fallback_lease_file)
+            return None
+
         LOG.debug("content is %s", content)
         option_name = _get_dhcp_endpoint_option_name()
         for line in content.splitlines():
@@ -372,9 +378,9 @@ class WALinuxAgentShim(object):
                           fallback_lease_file)
                 value = WALinuxAgentShim._get_value_from_leases_file(
                     fallback_lease_file)
-
         if value is None:
-            raise ValueError('No endpoint found.')
+            LOG.warning("No lease found; using default endpoint")
+            value = DEFAULT_WIRESERVER_ENDPOINT
 
         endpoint_ip_address = WALinuxAgentShim.get_ip_from_lease_value(value)
         LOG.debug('Azure endpoint found at %s', endpoint_ip_address)
@@ -387,10 +393,11 @@ class WALinuxAgentShim(object):
         http_client = AzureEndpointHttpClient(self.openssl_manager.certificate)
         LOG.info('Registering with Azure...')
         attempts = 0
+        endpoint = self.endpoint
         while True:
             try:
                 response = http_client.get(
-                    'http://{0}/machine/?comp=goalstate'.format(self.endpoint))
+                    'http://{0}/machine/?comp=goalstate'.format(endpoint))
             except Exception:
                 if attempts < 10:
                     time.sleep(attempts + 1)
diff --git a/tests/unittests/test_datasource/test_azure_helper.py b/tests/unittests/test_datasource/test_azure_helper.py
index 0255616..0018d46 100644
--- a/tests/unittests/test_datasource/test_azure_helper.py
+++ b/tests/unittests/test_datasource/test_azure_helper.py
@@ -67,12 +67,12 @@ class TestFindEndpoint(CiTestCase):
         self.networkd_leases.return_value = None
 
     def test_missing_file(self):
-        self.assertRaises(ValueError, wa_shim.find_endpoint)
+        self.assertEqual(wa_shim.find_endpoint(), "168.63.129.16")
 
     def test_missing_special_azure_line(self):
         self.load_file.return_value = ''
         self.dhcp_options.return_value = {'eth0': {'key': 'value'}}
-        self.assertRaises(ValueError, wa_shim.find_endpoint)
+        self.assertEqual(wa_shim.find_endpoint(), "168.63.129.16")
 
     @staticmethod
     def _build_lease_content(encoded_address):