Merge ~adam-collard/maas:flaky-dns-ipv4-no-gateways into maas:master

[Adam Collard]

fix: get_default_dns_servers relied on ordering of routable ips

The flaky test was dependent on ordering of ips which were never
explicitly ordered.

We now sort the addresses, relying on IPAddresses sorting v4 lower
than v6, and have a reliable IP to pick for the DNS server (one that
is routable from the node).

[MAAS Lander (maas-lander)]

UNIT TESTS
-b flaky-dns-ipv4-no-gateways lp:~adam-collard/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: FAILED
LOG: http://maas-ci.internal:8080/job/maas-tester/2594/console
COMMIT: 9c56cc5211e052745d69f5d01d60fb1d88d7ab29

review: Needs Fixing

[MAAS Lander (maas-lander)]

UNIT TESTS
-b flaky-dns-ipv4-no-gateways lp:~adam-collard/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: 7a6684957ea30591f895ab5599e74b7fd4753815

review: Approve

[Anton Troyanov (troyanov)]

review: Approve

diff --git a/src/maasserver/models/node.py b/src/maasserver/models/node.py
index 4fdaf59..d1f3165 100644
--- a/src/maasserver/models/node.py
+++ b/src/maasserver/models/node.py
@@ -5251,14 +5251,14 @@ class Node(CleanSave, TimestampedModel):
             # node with no gateway can only use routable addrs
             maas_dns_servers = []
             routable_addrs_map = {
-                node: [
+                node: sorted(
                     address
                     for address in addresses
                     if (
                         (ipv4 and address.version == 4)
                         or (ipv6 and address.version == 6)
                     )
-                ]
+                )
                 for node, addresses in routable_addrs_map.items()
             }
         else:
diff --git a/src/maasserver/models/tests/test_node.py b/src/maasserver/models/tests/test_node.py
index 601fb32..52ee395 100644
--- a/src/maasserver/models/tests/test_node.py
+++ b/src/maasserver/models/tests/test_node.py
@@ -22,7 +22,6 @@ from fixtures import LoggerFixture
 from netaddr import IPAddress, IPNetwork
 from testscenarios import multiply_scenarios
 from testtools import ExpectedException
-from testtools.content import text_content
 from testtools.matchers import (
     AfterPreprocessing,
     Contains,
@@ -140,7 +139,6 @@ from maasserver.preseed import CURTIN_INSTALL_LOG
 from maasserver.preseed_network import compose_curtin_network_config
 from maasserver.preseed_storage import compose_curtin_storage_config
 from maasserver.rbac import FakeRBACClient, rbac
-from maasserver.routablepairs import get_routable_address_map
 from maasserver.rpc.testing.fixtures import MockLiveRegionToClusterRPCFixture
 from maasserver.secrets import SecretManager
 from maasserver.storage_layouts import (
@@ -8804,29 +8802,6 @@ class TestGetDefaultDNSServers(MAASServerTestCase):
         rack_v4, rack_v6, node = self.make_Node_with_RackController(
             ipv4=True, ipv4_gateway=False, ipv6=True, ipv6_gateway=False
         )
-        # XXX this test fails randomly, this is to get more info if it does
-        self.addDetail(
-            "node.get_default_gateways",
-            text_content(repr(node.get_default_gateways())),
-        )
-        self.addDetail(
-            "node.get_boot_rack_controller",
-            text_content(repr(node.get_boot_rack_controller())),
-        )
-        self.addDetail(
-            "use_rack_proxy",
-            text_content(repr(Config.objects.get_config("use_rack_proxy"))),
-        )
-        self.addDetail(
-            "routable_address_map",
-            text_content(
-                repr(
-                    get_routable_address_map(
-                        RackController.objects.all(), node
-                    )
-                )
-            ),
-        )
         self.assertEqual([rack_v4], node.get_default_dns_servers())
 
     def test_uses_rack_ipv4_if_dual_stack_with_ipv4_gateway(self):
@@ -8966,9 +8941,7 @@ class TestGetDefaultDNSServers(MAASServerTestCase):
             ipv6=False, ipv4_subnet_dns=[ipv4_subnet_dns]
         )
         Subnet.objects.update(allow_dns=False)
-        self.assertCountEqual(
-            node.get_default_dns_servers(), [ipv4_subnet_dns]
-        )
+        self.assertEqual(node.get_default_dns_servers(), [ipv4_subnet_dns])
 
     def test_uses_subnet_ipv6_dns_only(self):
         # Regression test for LP:1847537
@@ -8977,29 +8950,17 @@ class TestGetDefaultDNSServers(MAASServerTestCase):
             ipv4=False, ipv6_subnet_dns=[ipv6_subnet_dns]
         )
         Subnet.objects.update(allow_dns=False)
-        self.assertCountEqual(
-            node.get_default_dns_servers(), [ipv6_subnet_dns]
-        )
+        self.assertEqual(node.get_default_dns_servers(), [ipv6_subnet_dns])
 
     def test_ignores_other_unroutable_rack_controllers_ipv4(self):
         # Regression test for LP:1896684
         rack_v4, rack_v6, node = self.make_Node_with_RackController(
             ipv4=True, ipv4_gateway=False, ipv6=False, ipv6_gateway=False
         )
-        vlan = node.boot_interface.vlan
-        rack = vlan.primary_rack
-        rackif = rack.current_config.interface_set.first()
-        rack_ips = [rack_v4]
-        for _ in range(3):
-            subnet = factory.make_Subnet(vlan=vlan, version=4)
-            ip = factory.make_StaticIPAddress(subnet=subnet, interface=rackif)
-            rack_ips.append(ip.ip)
-        rack.save()
-        resolve_hostname = self.patch(server_address, "resolve_hostname")
-        resolve_hostname.side_effect = lambda hostname, version: set(
-            map(IPAddress, rack_ips)
-        )
-        self.assertCountEqual(node.get_default_dns_servers(), [rack_v4])
+        rack = node.boot_interface.vlan.primary_rack
+        mock_address_map = self.patch(node_module, "get_routable_address_map")
+        mock_address_map.return_value = {rack: [IPAddress(rack_v4)]}
+        self.assertEqual(node.get_default_dns_servers(), [rack_v4])
 
 
 class TestNode_Start(MAASTransactionServerTestCase):