From f0fb841883b80c71618582e43e1b3cd87a0dcb58 Mon Sep 17 00:00:00 2001
From: Major Hayden <major@redhat.com>
Date: Mon, 1 Apr 2024 18:28:12 +0000
Subject: [PATCH] ec2: Do not enable dhcp6 on EC2 (#5104)

When cloud-init finds any ipv6 information in the instance metadata, it
automatically enables dhcp6 for the network interface. However, this
brings up the instance with a broken IPv6 configuration because SLAAC
should be used for almost all situations on EC2.

Red Hat BZ: https://bugzilla.redhat.com/show_bug.cgi?id=2092459
Fedora Pagure: https://pagure.io/cloud-sig/issue/382
Upstream: https://bugs.launchpad.net/cloud-init/+bug/1976526

Fixes GH-3980

Signed-off-by: Major Hayden <major@redhat.com>
---
 cloudinit/sources/DataSourceEc2.py  |  5 -----
 tests/unittests/sources/test_ec2.py | 15 +++++++--------
 2 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/cloudinit/sources/DataSourceEc2.py b/cloudinit/sources/DataSourceEc2.py
index 9e6bfbd..fbc7761 100644
--- a/cloudinit/sources/DataSourceEc2.py
+++ b/cloudinit/sources/DataSourceEc2.py
@@ -921,8 +921,6 @@ def convert_ec2_metadata_network_config(
             "set-name": nic_name,
         }
         nic_metadata = macs_metadata.get(mac)
-        if nic_metadata.get("ipv6s"):  # Any IPv6 addresses configured
-            dev_config["dhcp6"] = True
         netcfg["ethernets"][nic_name] = dev_config
         return netcfg
     # Apply network config for all nics and any secondary IPv4/v6 addresses
@@ -942,9 +940,6 @@ def convert_ec2_metadata_network_config(
             "match": {"macaddress": mac.lower()},
             "set-name": nic_name,
         }
-        if nic_metadata.get("ipv6s"):  # Any IPv6 addresses configured
-            dev_config["dhcp6"] = True
-            dev_config["dhcp6-overrides"] = dhcp_override
         dev_config["addresses"] = get_secondary_addresses(nic_metadata, mac)
         if not dev_config["addresses"]:
             dev_config.pop("addresses")  # Since we found none configured
diff --git a/tests/unittests/sources/test_ec2.py b/tests/unittests/sources/test_ec2.py
index ea8621a..a6801fa 100644
--- a/tests/unittests/sources/test_ec2.py
+++ b/tests/unittests/sources/test_ec2.py
@@ -432,7 +432,7 @@ class TestEc2(test_helpers.ResponsesTestCase):
                     "match": {"macaddress": "06:17:04:d7:26:09"},
                     "set-name": "eth9",
                     "dhcp4": True,
-                    "dhcp6": True,
+                    "dhcp6": False,
                 }
             },
         }
@@ -513,7 +513,7 @@ class TestEc2(test_helpers.ResponsesTestCase):
                         "2600:1f16:292:100:f153:12a3:c37c:11f9/128",
                     ],
                     "dhcp4": True,
-                    "dhcp6": True,
+                    "dhcp6": False,
                 }
             },
         }
@@ -593,7 +593,7 @@ class TestEc2(test_helpers.ResponsesTestCase):
                     "match": {"macaddress": mac1},
                     "set-name": "eth9",
                     "dhcp4": True,
-                    "dhcp6": True,
+                    "dhcp6": False,
                 }
             },
         }
@@ -1001,7 +1001,7 @@ class TestConvertEc2MetadataNetworkConfig(test_helpers.CiTestCase):
                     "match": {"macaddress": self.mac1},
                     "set-name": "eth9",
                     "dhcp4": True,
-                    "dhcp6": True,
+                    "dhcp6": False,
                 }
             },
         }
@@ -1078,7 +1078,7 @@ class TestConvertEc2MetadataNetworkConfig(test_helpers.CiTestCase):
                     "match": {"macaddress": self.mac1},
                     "set-name": "eth9",
                     "dhcp4": True,
-                    "dhcp6": True,
+                    "dhcp6": False,
                 }
             },
         }
@@ -1108,8 +1108,7 @@ class TestConvertEc2MetadataNetworkConfig(test_helpers.CiTestCase):
                     "set-name": "eth9",
                     "dhcp4": True,
                     "dhcp4-overrides": {"route-metric": 100},
-                    "dhcp6": True,
-                    "dhcp6-overrides": {"route-metric": 100},
+                    "dhcp6": False,
                 },
                 "eth10": {
                     "match": {"macaddress": mac2},
@@ -1140,7 +1139,7 @@ class TestConvertEc2MetadataNetworkConfig(test_helpers.CiTestCase):
                     "match": {"macaddress": self.mac1},
                     "set-name": "eth9",
                     "dhcp4": True,
-                    "dhcp6": True,
+                    "dhcp6": False,
                 }
             },
         }
-- 
2.33.0