Merge lp:~mpontillo/maas/gateway-with-auto-ip--bug-1671891 into lp:maas/2.1

[Mike Pontillo]

Fix deployment with AUTO IPs set as the gateway link. (Merge revision 5820 from trunk.)

 * Previously the gateway link would be thrown away and replaced.
   Now the existing link will be updated with the allocated
   IP address.

-

[Mike Pontillo (mpontillo)]

Self-approve backport, just in case we need to release 2.1.x again.

review: Approve

=== modified file 'docs/changelog.rst'
--- docs/changelog.rst	2017-03-01 15:54:17 +0000
+++ docs/changelog.rst	2017-03-17 23:26:59 +0000
@@ -36,6 +36,8 @@
 
 LP: #1665143    Select the shortest by-id path when discovering block devices to address issues when discovering nvme devices.
 
+LP: #1671891    Fix deployment with AUTO IPs set as the gateway link.
+
 
 Other notable changes
 ---------------------
 
=== modified file 'src/maasserver/models/interface.py'
--- src/maasserver/models/interface.py	2016-12-07 12:59:10 +0000
+++ src/maasserver/models/interface.py	2017-03-17 23:26:59 +0000
@@ -1055,13 +1055,15 @@
         new_ip = StaticIPAddress.objects.allocate_new(
             subnet=subnet, alloc_type=IPADDRESS_TYPE.AUTO,
             exclude_addresses=exclude_addresses)
-        self.ip_addresses.add(new_ip)
+        auto_ip.ip = new_ip.ip
+        # Throw away the newly-allocated address and assign it to the old AUTO
+        # address, so that the interface link IDs remain consistent.
+        new_ip.delete()
+        auto_ip.save()
         maaslog.info("Allocated automatic IP address %s for %s." % (
-            new_ip.ip,
+            auto_ip.ip,
             self.get_log_string()))
-
-        auto_ip.delete()
-        return new_ip
+        return auto_ip
 
     def release_auto_ips(self):
         """Release all AUTO IP address for this interface that have an IP
 
=== modified file 'src/maasserver/models/tests/test_interface.py'
--- src/maasserver/models/tests/test_interface.py	2016-12-07 12:59:10 +0000
+++ src/maasserver/models/tests/test_interface.py	2017-03-17 23:26:59 +0000
@@ -2661,6 +2661,36 @@
             "Should have 3 AUTO IP addresses with an IP address assigned.")
         self.assertItemsEqual(assigned_addresses, observed)
 
+    def test__keeps_ip_address_ids_consistent(self):
+        auto_ip_ids = []
+        with transaction.atomic():
+            interface = factory.make_Interface(INTERFACE_TYPE.PHYSICAL)
+            for _ in range(3):
+                subnet = factory.make_ipv4_Subnet_with_IPRanges(
+                    vlan=interface.vlan)
+                auto_ip = factory.make_StaticIPAddress(
+                    alloc_type=IPADDRESS_TYPE.AUTO, ip="",
+                    subnet=subnet, interface=interface)
+                auto_ip_ids.append(auto_ip.id)
+        with transaction.atomic():
+            observed = interface.claim_auto_ips()
+        # Should now have 3 AUTO with IP addresses assigned.
+        interface = reload_object(interface)
+        assigned_addresses = interface.ip_addresses.filter(
+            alloc_type=IPADDRESS_TYPE.AUTO)
+        assigned_addresses = [
+            ip
+            for ip in assigned_addresses
+            if ip.ip
+        ]
+        self.assertEqual(
+            3, len(assigned_addresses),
+            "Should have 3 AUTO IP addresses with an IP address assigned.")
+        self.assertItemsEqual(assigned_addresses, observed)
+        # Make sure the IDs didn't change upon allocation.
+        self.assertItemsEqual(
+            auto_ip_ids, (ip.id for ip in assigned_addresses))
+
     def test__claims_all_missing_assigned_auto_ip_addresses(self):
         with transaction.atomic():
             interface = factory.make_Interface(INTERFACE_TYPE.PHYSICAL)