rbxcloud: gracefully handle arping errors (#262)

2 files changed, 42 insertions, 5 deletions

diff --git a/cloudinit/sources/DataSourceRbxCloud.py b/cloudinit/sources/DataSourceRbxCloud.py
index c3cd5c79..084cb7d5 100644
--- a/cloudinit/sources/DataSourceRbxCloud.py
+++ b/cloudinit/sources/DataSourceRbxCloud.py
@@ -55,11 +55,18 @@ def gratuitous_arp(items, distro):
     if distro.name in ['fedora', 'centos', 'rhel']:
         source_param = '-s'
     for item in items:
-        _sub_arp([
-            '-c', '2',
-            source_param, item['source'],
-            item['destination']
-        ])
+        try:
+            _sub_arp([
+                '-c', '2',
+                source_param, item['source'],
+                item['destination']
+            ])
+        except util.ProcessExecutionError as error:
+            # warning, because the system is able to function properly
+            # despite no success - some ARP table may be waiting for
+            # expiration, but the system may continue
+            LOG.warning('Failed to arping from "%s" to "%s": %s',
+                        item['source'], item['destination'], error)
 
 
 def get_md():
diff --git a/tests/unittests/test_datasource/test_rbx.py b/tests/unittests/test_datasource/test_rbx.py
index aabf1f18..553af62e 100644
--- a/tests/unittests/test_datasource/test_rbx.py
+++ b/tests/unittests/test_datasource/test_rbx.py
@@ -4,6 +4,7 @@ from cloudinit import helpers
 from cloudinit import distros
 from cloudinit.sources import DataSourceRbxCloud as ds
 from cloudinit.tests.helpers import mock, CiTestCase, populate_dir
+from cloudinit import util
 
 DS_PATH = "cloudinit.sources.DataSourceRbxCloud"
 
@@ -199,6 +200,35 @@ class TestRbxDataSource(CiTestCase):
             m_subp.call_args_list
         )
 
+    @mock.patch(
+        DS_PATH + '.util.subp',
+        side_effect=util.ProcessExecutionError()
+    )
+    def test_continue_on_arping_error(self, m_subp):
+        """Continue when command error"""
+        items = [
+            {
+                'destination': '172.17.0.2',
+                'source': '172.16.6.104'
+            },
+            {
+                'destination': '172.17.0.2',
+                'source': '172.16.6.104',
+            },
+        ]
+        ds.gratuitous_arp(items, self._fetch_distro('ubuntu'))
+        self.assertEqual([
+            mock.call([
+                'arping', '-c', '2', '-S',
+                '172.16.6.104', '172.17.0.2'
+            ]),
+            mock.call([
+                'arping', '-c', '2', '-S',
+                '172.16.6.104', '172.17.0.2'
+            ])
+        ], m_subp.call_args_list
+        )
+
 
 def populate_cloud_metadata(path, data):
     populate_dir(path, {'cloud.json': json.dumps(data)})