From f844e9c263e59a623ca8c647bd87bf4f91374d54 Mon Sep 17 00:00:00 2001
From: Thomas Stringer <thstring@microsoft.com>
Date: Wed, 3 Mar 2021 11:07:43 -0500
Subject: [PATCH 1/7] Add flexibility to IMDS api-version (#793)
RH-Author: Eduardo Otubo <otubo@redhat.com>
RH-MergeRequest: 18: Add support for userdata on Azure from IMDS
RH-Commit: [1/7] 99a3db20e3f277a2f12ea21e937e06939434a2ca (otubo/cloud-init-src)
RH-Bugzilla: 2042351
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Acked-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Add flexibility to IMDS api-version by having both a desired IMDS
api-version and a minimum api-version. The desired api-version will
be used first, and if that fails it will fall back to the minimum
api-version.
---
cloudinit/sources/DataSourceAzure.py | 113 ++++++++++++++----
tests/unittests/test_datasource/test_azure.py | 42 ++++++-
2 files changed, 129 insertions(+), 26 deletions(-)
diff --git a/cloudinit/sources/DataSourceAzure.py b/cloudinit/sources/DataSourceAzure.py
index 553b5a7e..de1452ce 100755
--- a/cloudinit/sources/DataSourceAzure.py
+++ b/cloudinit/sources/DataSourceAzure.py
@@ -78,17 +78,15 @@ AGENT_SEED_DIR = '/var/lib/waagent'
# In the event where the IMDS primary server is not
# available, it takes 1s to fallback to the secondary one
IMDS_TIMEOUT_IN_SECONDS = 2
-IMDS_URL = "http://169.254.169.254/metadata/"
-IMDS_VER = "2019-06-01"
-IMDS_VER_PARAM = "api-version={}".format(IMDS_VER)
+IMDS_URL = "http://169.254.169.254/metadata"
+IMDS_VER_MIN = "2019-06-01"
+IMDS_VER_WANT = "2020-09-01"
class metadata_type(Enum):
- compute = "{}instance?{}".format(IMDS_URL, IMDS_VER_PARAM)
- network = "{}instance/network?{}".format(IMDS_URL,
- IMDS_VER_PARAM)
- reprovisiondata = "{}reprovisiondata?{}".format(IMDS_URL,
- IMDS_VER_PARAM)
+ compute = "{}/instance".format(IMDS_URL)
+ network = "{}/instance/network".format(IMDS_URL)
+ reprovisiondata = "{}/reprovisiondata".format(IMDS_URL)
PLATFORM_ENTROPY_SOURCE = "/sys/firmware/acpi/tables/OEM0"
@@ -349,6 +347,8 @@ class DataSourceAzure(sources.DataSource):
self.update_events['network'].add(EventType.BOOT)
self._ephemeral_dhcp_ctx = None
+ self.failed_desired_api_version = False
+
def __str__(self):
root = sources.DataSource.__str__(self)
return "%s [seed=%s]" % (root, self.seed)
@@ -520,8 +520,10 @@ class DataSourceAzure(sources.DataSource):
self._wait_for_all_nics_ready()
ret = self._reprovision()
- imds_md = get_metadata_from_imds(
- self.fallback_interface, retries=10)
+ imds_md = self.get_imds_data_with_api_fallback(
+ self.fallback_interface,
+ retries=10
+ )
(md, userdata_raw, cfg, files) = ret
self.seed = cdev
crawled_data.update({
@@ -652,6 +654,57 @@ class DataSourceAzure(sources.DataSource):
self.ds_cfg['data_dir'], crawled_data['files'], dirmode=0o700)
return True
+ @azure_ds_telemetry_reporter
+ def get_imds_data_with_api_fallback(
+ self,
+ fallback_nic,
+ retries,
+ md_type=metadata_type.compute):
+ """
+ Wrapper for get_metadata_from_imds so that we can have flexibility
+ in which IMDS api-version we use. If a particular instance of IMDS
+ does not have the api version that is desired, we want to make
+ this fault tolerant and fall back to a good known minimum api
+ version.
+ """
+
+ if not self.failed_desired_api_version:
+ for _ in range(retries):
+ try:
+ LOG.info(
+ "Attempting IMDS api-version: %s",
+ IMDS_VER_WANT
+ )
+ return get_metadata_from_imds(
+ fallback_nic=fallback_nic,
+ retries=0,
+ md_type=md_type,
+ api_version=IMDS_VER_WANT
+ )
+ except UrlError as err:
+ LOG.info(
+ "UrlError with IMDS api-version: %s",
+ IMDS_VER_WANT
+ )
+ if err.code == 400:
+ log_msg = "Fall back to IMDS api-version: {}".format(
+ IMDS_VER_MIN
+ )
+ report_diagnostic_event(
+ log_msg,
+ logger_func=LOG.info
+ )
+ self.failed_desired_api_version = True
+ break
+
+ LOG.info("Using IMDS api-version: %s", IMDS_VER_MIN)
+ return get_metadata_from_imds(
+ fallback_nic=fallback_nic,
+ retries=retries,
+ md_type=md_type,
+ api_version=IMDS_VER_MIN
+ )
+
def device_name_to_device(self, name):
return self.ds_cfg['disk_aliases'].get(name)
@@ -880,10 +933,11 @@ class DataSourceAzure(sources.DataSource):
# primary nic is being attached first helps here. Otherwise each nic
# could add several seconds of delay.
try:
- imds_md = get_metadata_from_imds(
+ imds_md = self.get_imds_data_with_api_fallback(
ifname,
5,
- metadata_type.network)
+ metadata_type.network
+ )
except Exception as e:
LOG.warning(
"Failed to get network metadata using nic %s. Attempt to "
@@ -1017,7 +1071,10 @@ class DataSourceAzure(sources.DataSource):
def _poll_imds(self):
"""Poll IMDS for the new provisioning data until we get a valid
response. Then return the returned JSON object."""
- url = metadata_type.reprovisiondata.value
+ url = "{}?api-version={}".format(
+ metadata_type.reprovisiondata.value,
+ IMDS_VER_MIN
+ )
headers = {"Metadata": "true"}
nl_sock = None
report_ready = bool(not os.path.isfile(REPORTED_READY_MARKER_FILE))
@@ -2059,7 +2116,8 @@ def _generate_network_config_from_fallback_config() -> dict:
@azure_ds_telemetry_reporter
def get_metadata_from_imds(fallback_nic,
retries,
- md_type=metadata_type.compute):
+ md_type=metadata_type.compute,
+ api_version=IMDS_VER_MIN):
"""Query Azure's instance metadata service, returning a dictionary.
If network is not up, setup ephemeral dhcp on fallback_nic to talk to the
@@ -2069,13 +2127,16 @@ def get_metadata_from_imds(fallback_nic,
@param fallback_nic: String. The name of the nic which requires active
network in order to query IMDS.
@param retries: The number of retries of the IMDS_URL.
+ @param md_type: Metadata type for IMDS request.
+ @param api_version: IMDS api-version to use in the request.
@return: A dict of instance metadata containing compute and network
info.
"""
kwargs = {'logfunc': LOG.debug,
'msg': 'Crawl of Azure Instance Metadata Service (IMDS)',
- 'func': _get_metadata_from_imds, 'args': (retries, md_type,)}
+ 'func': _get_metadata_from_imds,
+ 'args': (retries, md_type, api_version,)}
if net.is_up(fallback_nic):
return util.log_time(**kwargs)
else:
@@ -2091,20 +2152,26 @@ def get_metadata_from_imds(fallback_nic,
@azure_ds_telemetry_reporter
-def _get_metadata_from_imds(retries, md_type=metadata_type.compute):
-
- url = md_type.value
+def _get_metadata_from_imds(
+ retries,
+ md_type=metadata_type.compute,
+ api_version=IMDS_VER_MIN):
+ url = "{}?api-version={}".format(md_type.value, api_version)
headers = {"Metadata": "true"}
try:
response = readurl(
url, timeout=IMDS_TIMEOUT_IN_SECONDS, headers=headers,
retries=retries, exception_cb=retry_on_url_exc)
except Exception as e:
- report_diagnostic_event(
- 'Ignoring IMDS instance metadata. '
- 'Get metadata from IMDS failed: %s' % e,
- logger_func=LOG.warning)
- return {}
+ # pylint:disable=no-member
+ if isinstance(e, UrlError) and e.code == 400:
+ raise
+ else:
+ report_diagnostic_event(
+ 'Ignoring IMDS instance metadata. '
+ 'Get metadata from IMDS failed: %s' % e,
+ logger_func=LOG.warning)
+ return {}
try:
from json.decoder import JSONDecodeError
json_decode_error = JSONDecodeError
diff --git a/tests/unittests/test_datasource/test_azure.py b/tests/unittests/test_datasource/test_azure.py
index f597c723..dedebeb1 100644
--- a/tests/unittests/test_datasource/test_azure.py
+++ b/tests/unittests/test_datasource/test_azure.py
@@ -408,7 +408,9 @@ class TestGetMetadataFromIMDS(HttprettyTestCase):
def setUp(self):
super(TestGetMetadataFromIMDS, self).setUp()
- self.network_md_url = dsaz.IMDS_URL + "instance?api-version=2019-06-01"
+ self.network_md_url = "{}/instance?api-version=2019-06-01".format(
+ dsaz.IMDS_URL
+ )
@mock.patch(MOCKPATH + 'readurl')
@mock.patch(MOCKPATH + 'EphemeralDHCPv4', autospec=True)
@@ -518,7 +520,7 @@ class TestGetMetadataFromIMDS(HttprettyTestCase):
"""Return empty dict when IMDS network metadata is absent."""
httpretty.register_uri(
httpretty.GET,
- dsaz.IMDS_URL + 'instance?api-version=2017-12-01',
+ dsaz.IMDS_URL + '/instance?api-version=2017-12-01',
body={}, status=404)
m_net_is_up.return_value = True # skips dhcp
@@ -1877,6 +1879,40 @@ scbus-1 on xpt0 bus 0
ssh_keys = dsrc.get_public_ssh_keys()
self.assertEqual(ssh_keys, ['key2'])
+ @mock.patch(MOCKPATH + 'get_metadata_from_imds')
+ def test_imds_api_version_wanted_nonexistent(
+ self,
+ m_get_metadata_from_imds):
+ def get_metadata_from_imds_side_eff(*args, **kwargs):
+ if kwargs['api_version'] == dsaz.IMDS_VER_WANT:
+ raise url_helper.UrlError("No IMDS version", code=400)
+ return NETWORK_METADATA
+ m_get_metadata_from_imds.side_effect = get_metadata_from_imds_side_eff
+ sys_cfg = {'datasource': {'Azure': {'apply_network_config': True}}}
+ odata = {'HostName': "myhost", 'UserName': "myuser"}
+ data = {
+ 'ovfcontent': construct_valid_ovf_env(data=odata),
+ 'sys_cfg': sys_cfg
+ }
+ dsrc = self._get_ds(data)
+ dsrc.get_data()
+ self.assertIsNotNone(dsrc.metadata)
+ self.assertTrue(dsrc.failed_desired_api_version)
+
+ @mock.patch(
+ MOCKPATH + 'get_metadata_from_imds', return_value=NETWORK_METADATA)
+ def test_imds_api_version_wanted_exists(self, m_get_metadata_from_imds):
+ sys_cfg = {'datasource': {'Azure': {'apply_network_config': True}}}
+ odata = {'HostName': "myhost", 'UserName': "myuser"}
+ data = {
+ 'ovfcontent': construct_valid_ovf_env(data=odata),
+ 'sys_cfg': sys_cfg
+ }
+ dsrc = self._get_ds(data)
+ dsrc.get_data()
+ self.assertIsNotNone(dsrc.metadata)
+ self.assertFalse(dsrc.failed_desired_api_version)
+
class TestAzureBounce(CiTestCase):
@@ -2657,7 +2693,7 @@ class TestPreprovisioningHotAttachNics(CiTestCase):
@mock.patch(MOCKPATH + 'DataSourceAzure.wait_for_link_up')
@mock.patch('cloudinit.sources.helpers.netlink.wait_for_nic_attach_event')
@mock.patch('cloudinit.sources.net.find_fallback_nic')
- @mock.patch(MOCKPATH + 'get_metadata_from_imds')
+ @mock.patch(MOCKPATH + 'DataSourceAzure.get_imds_data_with_api_fallback')
@mock.patch(MOCKPATH + 'EphemeralDHCPv4')
@mock.patch(MOCKPATH + 'DataSourceAzure._wait_for_nic_detach')
@mock.patch('os.path.isfile')
--
2.27.0