Makes tap device name consistent

Keeping device names used by Kuryr consistent with those used
by Nova makes the users' and operators' experience better. It
also makes debugging easier for those used to names employed by
Nova. This patch set changes the tap device name to use part of
the Neutron port id.

Closes-Bug: #1582348
Change-Id: I502f7bba09044106885de28cef8a432d5b5b1321

kuryr/binding.py

@@ -22,8 +22,6 @@ from kuryr.common import exceptions
 from kuryr import utils
 
 
-VETH_PREFIX = 'tap'
-CONTAINER_VETH_PREFIX = 't_c'
 BINDING_SUBCOMMAND = 'bind'
 DOWN = 'DOWN'
 FALLBACK_VIF_TYPE = 'unbound'
@@ -115,8 +113,8 @@ def port_bind(endpoint_id, neutron_port, neutron_subnets):
     """
     ip = get_ipdb()
 
-    ifname = VETH_PREFIX + endpoint_id[:8]
-    peer_name = CONTAINER_VETH_PREFIX + ifname
+    port_id = neutron_port['id']
+    ifname, peer_name = utils.get_veth_pair_names(port_id)
     subnets_dict = {subnet['id']: subnet for subnet in neutron_subnets}
 
     try:
@@ -176,8 +174,10 @@ def port_unbind(endpoint_id, neutron_port):
     vif_type = neutron_port.get(VIF_TYPE_KEY, FALLBACK_VIF_TYPE)
     vif_details = utils.string_mappings(neutron_port.get(VIF_DETAILS_KEY))
     unbinding_exec_path = os.path.join(config.CONF.bindir, vif_type)
-    ifname = VETH_PREFIX + endpoint_id[:8]
+
     port_id = neutron_port['id']
+    ifname, _ = utils.get_veth_pair_names(port_id)
+
     mac_address = neutron_port['mac_address']
     stdout, stderr = processutils.execute(
         unbinding_exec_path, UNBINDING_SUBCOMMAND, port_id, ifname,

kuryr/common/constants.py

@@ -19,6 +19,9 @@ SCHEMA = {
 }
 
 DEVICE_OWNER = 'kuryr:container'
+NIC_NAME_LEN = 14
+VETH_PREFIX = 'tap'
+CONTAINER_VETH_PREFIX = 't_c'
 
 NEUTRON_ID_LH_OPTION = 'kuryr.net.uuid.lh'
 NEUTRON_ID_UH_OPTION = 'kuryr.net.uuid.uh'

kuryr/tests/unit/test_join.py

@@ -20,6 +20,7 @@ from werkzeug import exceptions as w_exceptions
 
 from kuryr import app
 from kuryr import binding
+from kuryr.common import constants as const
 from kuryr.common import exceptions
 from kuryr.tests.unit import base
 from kuryr import utils
@@ -47,7 +48,7 @@ class TestKuryrJoinFailures(base.TestKuryrFailures):
         fake_ifname = 'fake-veth'
         fake_binding_response = (
             fake_ifname,
-            binding.CONTAINER_VETH_PREFIX + fake_ifname,
+            const.CONTAINER_VETH_PREFIX + fake_ifname,
             ('fake stdout', '')
         )
         self.mox.StubOutWithMock(binding, 'port_bind')

kuryr/tests/unit/test_utils.py

@@ -11,10 +11,12 @@
 # under the License.
 
 import hashlib
+import uuid
 
 import ddt
 from oslo_config import cfg
 
+from kuryr.common import constants as const
 from kuryr.tests.unit import base
 from kuryr import utils
 
@@ -38,6 +40,22 @@ class TestKuryrUtils(base.TestKuryrBase):
         self.assertIn(utils.PORT_POSTFIX, generated_neutron_port_name)
         self.assertIn(fake_docker_endpoint_id, generated_neutron_port_name)
 
+    def test_get_veth_pair_names(self):
+        fake_neutron_port_id = str(uuid.uuid4())
+        generated_ifname, generated_peer = utils.get_veth_pair_names(
+            fake_neutron_port_id)
+
+        namelen = const.NIC_NAME_LEN
+        ifname_postlen = namelen - len(const.VETH_PREFIX)
+        peer_postlen = namelen - len(const.CONTAINER_VETH_PREFIX)
+
+        self.assertEqual(namelen, len(generated_ifname))
+        self.assertEqual(namelen, len(generated_peer))
+        self.assertIn(const.VETH_PREFIX, generated_ifname)
+        self.assertIn(const.CONTAINER_VETH_PREFIX, generated_peer)
+        self.assertIn(fake_neutron_port_id[:ifname_postlen], generated_ifname)
+        self.assertIn(fake_neutron_port_id[:peer_postlen], generated_peer)
+
     def test_get_subnetpool_name(self):
         fake_subnet_cidr = "10.0.0.0/16"
         generated_neutron_subnetpool_name = utils.get_neutron_subnetpool_name(

kuryr/utils.py

@@ -109,6 +109,14 @@ def get_neutron_port_name(docker_endpoint_id):
     return '-'.join([docker_endpoint_id, PORT_POSTFIX])
 
 
+def get_veth_pair_names(port_id):
+    ifname = const.VETH_PREFIX + port_id
+    ifname = ifname[:const.NIC_NAME_LEN]
+    peer_name = const.CONTAINER_VETH_PREFIX + port_id
+    peer_name = peer_name[:const.NIC_NAME_LEN]
+    return ifname, peer_name
+
+
 def get_hostname():
     """Returns the host name."""
     return socket.gethostname()