Merge ~r00ta/maas:lp-2049508-3.4 into maas:3.4

[Jacopo Rota]

fix: lp-2049508 cleanup leftover expired dynamic ips
(cherry picked from commit f8c31120b4a3d386418105d20daf90264f414fd3)

[MAAS Lander (maas-lander)]

UNIT TESTS
-b lp-2049508-3.4 lp:~r00ta/maas/+git/maas into -b 3.4 lp:~maas-committers/maas

STATUS: FAILED
LOG: http://maas-ci.internal:8080/job/maas-tester/4745/console
COMMIT: 4ccc7dceeb5ad7f135d707d0210b9b4d9ae320f6

review: Needs Fixing

[Jacopo Rota (r00ta)]

jenkins: !test

[Jacopo Rota (r00ta)]

self approving backport

review: Approve

[MAAS Lander (maas-lander)]

UNIT TESTS
-b lp-2049508-3.4 lp:~r00ta/maas/+git/maas into -b 3.4 lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: 4ccc7dceeb5ad7f135d707d0210b9b4d9ae320f6

review: Approve

diff --git a/src/maasserver/start_up.py b/src/maasserver/start_up.py
index 824eca2..f748089 100644
--- a/src/maasserver/start_up.py
+++ b/src/maasserver/start_up.py
@@ -3,7 +3,6 @@
 
 """Start-up utilities for the MAAS server."""
 
-
 import logging
 
 from django.db.utils import DatabaseError
@@ -15,9 +14,11 @@ from maasserver.deprecations import (
     log_deprecations,
     sync_deprecation_notifications,
 )
+from maasserver.enum import INTERFACE_TYPE, IPADDRESS_TYPE
 from maasserver.models import (
     Config,
     ControllerInfo,
+    Interface,
     Notification,
     RegionController,
 )
@@ -103,6 +104,22 @@ def migrate_db_credentials_if_necessary(client: VaultClient) -> None:
         logger.info("Deleted DB credentials from vault")
 
 
+def _cleanup_expired_discovered_ip_addresses() -> None:
+    """
+    This startup cleanup is needed for the following reasons:
+    - Major cleanup for https://bugs.launchpad.net/maas/+bug/2049508
+    - In case we missed some DHCP notifications related to discovered IP addresses, we clean up all the resources here.
+    """
+
+    # Delete all the dummy interfaces and IP addresses that have expired.
+    # The related DNS records will be deleted when the django post_delete signal is handled.
+    Interface.objects.filter(
+        type=INTERFACE_TYPE.UNKNOWN,
+        ip_addresses__ip__isnull=True,
+        ip_addresses__alloc_type=IPADDRESS_TYPE.DISCOVERED,
+    ).delete()
+
+
 @asynchronous(timeout=FOREVER)
 @inlineCallbacks
 def start_up(master=False):
@@ -195,6 +212,9 @@ def inner_start_up(master=False):
     # Only perform the following if the master process for the
     # region controller.
     if master:
+        # Cleanup in case we missed some DHCP notifications related to discovered ip addresses
+        _cleanup_expired_discovered_ip_addresses()
+
         # Migrate DB credentials to Vault and set the flag if Vault client is configured
         client = get_region_vault_client()
         if client is not None:
diff --git a/src/maasserver/tests/test_start_up.py b/src/maasserver/tests/test_start_up.py
index 8035787..e1f604f 100644
--- a/src/maasserver/tests/test_start_up.py
+++ b/src/maasserver/tests/test_start_up.py
@@ -9,6 +9,8 @@ from testtools.matchers import HasLength
 
 from maasserver import deprecations, eventloop, locks, start_up, vault
 from maasserver.config import RegionConfiguration
+from maasserver.enum import INTERFACE_TYPE, IPADDRESS_TYPE
+from maasserver.models import Interface, StaticIPAddress
 from maasserver.models.config import Config
 from maasserver.models.controllerinfo import ControllerInfo
 from maasserver.models.node import RegionController
@@ -322,6 +324,38 @@ class TestInnerStartUp(MAASServerTestCase):
 
         migrate_mock.assert_not_called()
 
+    def test_start_up_cleanup_expired_ip_addresses(self):
+        # When a host not managed by MAAS requests an IP to the MAAS DHCP server, the rack will notify the region about the
+        # event.
+        # If the mac_address if the DHCP lease is unknown, the region
+        # - creates an interface with type 'unknown'
+        # - creates a StaticIPAddress(alloc_type=IPADDRESS_TYPE.DISCOVERED)
+        # - attaches the ip address to the interface
+        unknown_interface = factory.make_Interface(
+            iftype=INTERFACE_TYPE.UNKNOWN,
+            name="eth0",
+        )
+
+        # We already set the IP to None for testing purposes.
+        ip = factory.make_StaticIPAddress(
+            alloc_type=IPADDRESS_TYPE.DISCOVERED,
+            ip=None,
+            interface=unknown_interface,
+        )
+
+        # Create also some other interfaces with IP addresses so to check that they are not deleted by the cleanup procedure.
+        for _ in range(5):
+            interface = factory.make_Interface()
+            factory.make_StaticIPAddress(interface=interface)
+
+        with post_commit_hooks:
+            start_up.inner_start_up(master=True)
+
+        assert not Interface.objects.filter(id=unknown_interface.id).exists()
+        assert not StaticIPAddress.objects.filter(id=ip.id).exists()
+        assert StaticIPAddress.objects.all().count() == 5
+        assert Interface.objects.all().count() == 5
+
 
 class TestVaultMigrateDbCredentials(MAASServerTestCase):
     def setUp(self):