From 635dcbf5a4a5b060ebf417c66789c59ebb28c39f Mon Sep 17 00:00:00 2001
From: Eduardo Otubo <otubo@redhat.com>
Date: Wed, 15 May 2019 12:15:28 +0200
Subject: [PATCH 4/5] DataSourceAzure: Adjust timeout for polling IMDS

RH-Author: Eduardo Otubo <otubo@redhat.com>
Message-id: <20190515121529.11191-5-otubo@redhat.com>
Patchwork-id: 87883
O-Subject: [rhel-7 cloud-init PATCHv2 4/5] DataSourceAzure: Adjust timeout for polling IMDS
Bugzilla: 1687565
RH-Acked-by: Vitaly Kuznetsov <vkuznets@redhat.com>
RH-Acked-by: Mohammed Gamal <mgamal@redhat.com>

From: Anh Vo <anhvo@microsoft.com>

BZ: 1687565
BRANCH: rhel7/master-18.5
UPSTREAM: ab6621d8
BREW: 21696239

commit ab6621d849b24bb652243e88c79f6f3b446048d7
Author: Anh Vo <anhvo@microsoft.com>
Date:   Wed May 8 14:54:03 2019 +0000

    DataSourceAzure: Adjust timeout for polling IMDS

    If the IMDS primary server is not available, falling back to the
    secondary server takes about 1s. The net result is that the
    expected E2E time is slightly more than 1s. This change increases
    the timeout to 2s to prevent the infinite loop of timeouts.

Signed-off-by: Eduardo Otubo <otubo@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 cloudinit/sources/DataSourceAzure.py          | 15 ++++++++++-----
 tests/unittests/test_datasource/test_azure.py | 10 +++++++---
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/cloudinit/sources/DataSourceAzure.py b/cloudinit/sources/DataSourceAzure.py
index c827816..5baf8da 100755
--- a/cloudinit/sources/DataSourceAzure.py
+++ b/cloudinit/sources/DataSourceAzure.py
@@ -57,7 +57,12 @@ AZURE_CHASSIS_ASSET_TAG = '7783-7084-3265-9085-8269-3286-77'
 REPROVISION_MARKER_FILE = "/var/lib/cloud/data/poll_imds"
 REPORTED_READY_MARKER_FILE = "/var/lib/cloud/data/reported_ready"
 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/"
+
 PLATFORM_ENTROPY_SOURCE = "/sys/firmware/acpi/tables/OEM0"
 
 # List of static scripts and network config artifacts created by
@@ -582,9 +587,9 @@ class DataSourceAzure(sources.DataSource):
                         return
                     self._ephemeral_dhcp_ctx.clean_network()
                 else:
-                    return readurl(url, timeout=1, headers=headers,
-                                   exception_cb=exc_cb, infinite=True,
-                                   log_req_resp=False).contents
+                    return readurl(url, timeout=IMDS_TIMEOUT_IN_SECONDS,
+                                   headers=headers, exception_cb=exc_cb,
+                                   infinite=True, log_req_resp=False).contents
             except UrlError:
                 # Teardown our EphemeralDHCPv4 context on failure as we retry
                 self._ephemeral_dhcp_ctx.clean_network()
@@ -1291,8 +1296,8 @@ def _get_metadata_from_imds(retries):
     headers = {"Metadata": "true"}
     try:
         response = readurl(
-            url, timeout=1, headers=headers, retries=retries,
-            exception_cb=retry_on_url_exc)
+            url, timeout=IMDS_TIMEOUT_IN_SECONDS, headers=headers,
+            retries=retries, exception_cb=retry_on_url_exc)
     except Exception as e:
         LOG.debug('Ignoring IMDS instance metadata: %s', e)
         return {}
diff --git a/tests/unittests/test_datasource/test_azure.py b/tests/unittests/test_datasource/test_azure.py
index eacf225..bc8b42c 100644
--- a/tests/unittests/test_datasource/test_azure.py
+++ b/tests/unittests/test_datasource/test_azure.py
@@ -163,7 +163,8 @@ class TestGetMetadataFromIMDS(HttprettyTestCase):
 
         m_readurl.assert_called_with(
             self.network_md_url, exception_cb=mock.ANY,
-            headers={'Metadata': 'true'}, retries=2, timeout=1)
+            headers={'Metadata': 'true'}, retries=2,
+            timeout=dsaz.IMDS_TIMEOUT_IN_SECONDS)
 
     @mock.patch('cloudinit.url_helper.time.sleep')
     @mock.patch(MOCKPATH + 'net.is_up')
@@ -1789,7 +1790,8 @@ class TestAzureDataSourcePreprovisioning(CiTestCase):
                                     headers={'Metadata': 'true',
                                              'User-Agent':
                                              'Cloud-Init/%s' % vs()
-                                             }, method='GET', timeout=1,
+                                             }, method='GET',
+                                    timeout=dsaz.IMDS_TIMEOUT_IN_SECONDS,
                                     url=full_url)])
         self.assertEqual(m_dhcp.call_count, 2)
         m_net.assert_any_call(
@@ -1826,7 +1828,9 @@ class TestAzureDataSourcePreprovisioning(CiTestCase):
                                     headers={'Metadata': 'true',
                                              'User-Agent':
                                              'Cloud-Init/%s' % vs()},
-                                    method='GET', timeout=1, url=full_url)])
+                                    method='GET',
+                                    timeout=dsaz.IMDS_TIMEOUT_IN_SECONDS,
+                                    url=full_url)])
         self.assertEqual(m_dhcp.call_count, 2)
         m_net.assert_any_call(
             broadcast='192.168.2.255', interface='eth9', ip='192.168.2.9',
-- 
1.8.3.1