Add cc_netplan_nm_patch module

Signed-off-by: paulober <44974737+paulober@users.noreply.github.com>

cloudinit/config/cc_netplan_nm_patch.py

@@ -0,0 +1,129 @@
+# Copyright (C) 2024, Raspberry Pi Ltd.
+#
+# Author: Paul Oberosler <paul.oberosler@raspberrypi.com>
+#
+# This file is part of cloud-init. See LICENSE file for license information.
+
+from cloudinit import subp
+from cloudinit.cloud import Cloud
+from cloudinit.config import Config
+from cloudinit.config.schema import MetaSchema
+from cloudinit.distros import ALL_DISTROS
+from cloudinit.net.netplan import CLOUDINIT_NETPLAN_FILE
+from cloudinit.settings import PER_INSTANCE
+import logging
+import os
+import re
+
+LOG = logging.getLogger(__name__)
+
+meta: MetaSchema = {
+    "id": "cc_netplan_nm_patch",
+    "distros": [ALL_DISTROS],
+    "frequency": PER_INSTANCE,
+    "activate_by_schema_keys": [],
+}
+
+
+def exec_cmd(command: str) -> str | None:
+    try:
+        result = subp.subp(command)
+        if result.stdout is not None:
+            return result.stdout
+    except subp.ProcessExecutionError as e:
+        LOG.error("Failed to execute command: %s", e)
+        return None
+    LOG.debug("Command has no stdout: %s", command)
+    return None
+
+
+def get_netplan_generated_configs() -> list[str]:
+    """Get the UUIDs of all connections starting with 'netplan-'."""
+    output = exec_cmd(["nmcli", "connection", "show"])
+    if output is None:
+        return []
+
+    netplan_conns = []
+    for line in output.splitlines():
+        if line.startswith("netplan-"):
+            parts = line.split()
+            if len(parts) > 1:
+                # name = parts[0]
+                uuid = parts[1]
+                netplan_conns.append(uuid)
+    return netplan_conns
+
+
+def get_connection_object_path(uuid: str) -> str | None:
+    """Get the D-Bus object path for a connection by UUID."""
+    output = exec_cmd(
+        [
+            "busctl",
+            "call",
+            "org.freedesktop.NetworkManager",
+            "/org/freedesktop/NetworkManager/Settings",
+            "org.freedesktop.NetworkManager.Settings",
+            "GetConnectionByUuid",
+            "s",
+            uuid,
+        ]
+    )
+
+    path_match = (
+        re.search(
+            r'o\s+"(/org/freedesktop/NetworkManager/Settings/\d+)"', output
+        )
+        if output
+        else None
+    )
+    if path_match:
+        return path_match.group(1)
+    else:
+        LOG.error("Failed to find object path for connection: %s", uuid)
+        return None
+
+
+def save_connection(obj_path: str) -> None:
+    """Call the Save method on the D-Bus obj path for a connection."""
+    result = exec_cmd(
+        [
+            "busctl",
+            "call",
+            "org.freedesktop.NetworkManager",
+            obj_path,
+            "org.freedesktop.NetworkManager.Settings.Connection",
+            "Save",
+        ]
+    )
+
+    if result is None:
+        LOG.error("Failed to save connection: %s", obj_path)
+    else:
+        LOG.debug("Saved connection: %s", obj_path)
+
+
+def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None:
+    LOG.debug("Applying netplan patch")
+
+    # remove cloud-init file after NetworkManager has generated
+    # replacement netplan configurations to avoid conflicts in the
+    # future
+
+    try:
+        np_conns = get_netplan_generated_configs()
+        if not np_conns:
+            LOG.debug("No netplan connections found")
+            return
+
+        for conn_uuid in np_conns:
+            obj_path = get_connection_object_path(conn_uuid)
+            if obj_path is None:
+                continue
+            save_connection(obj_path)
+
+        os.remove(CLOUDINIT_NETPLAN_FILE)
+        LOG.debug("Netplan cfg has been patched: %s", CLOUDINIT_NETPLAN_FILE)
+    except subp.ProcessExecutionError as e:
+        LOG.error("Failed to patch netplan cfg: %s", e)
+    except Exception as e:
+        LOG.error("Failed to patch netplan cfg: %s", e)

cloudinit/config/schemas/schema-cloud-config-v1.json

@@ -35,6 +35,7 @@
         "lxd",
         "mcollective",
         "mounts",
+        "netplan_nm_patch",
         "ntp",
         "package-update-upgrade-install",
         "package_update_upgrade_install",

config/cloud.cfg.tmpl

@@ -223,6 +223,9 @@ cloud_final_modules:
   - mcollective
   - salt_minion
   - reset_rmc
+{% endif %}
+{% if variant == "raspberry-pi-os" %}
+  - netplan_nm_patch
 {% endif %}
   - scripts_vendor
   - scripts_per_once

doc/module-docs/cc_netplan_nm_patch/data.yaml

@@ -0,0 +1,12 @@
+cc_netplan_nm_patch:
+  description: |
+    This module resolves the issue where if you edit a netplan generated network configuration
+    in NetworkManager, the changes are saved to netplan as new configuration files.
+    This will cause netplan overwrite the NetworkManager generated netplan configuration on the next boot.
+
+    This module will give NetworkManager a hint to generated netplan configuration files
+    and then removes the cloud-init generated netplan configuration file.
+
+    This module expects that NetworkManager has the netplan integration patch applied.
+  name: Netplan NetworkManager Patch
+  title: Patch NetworkManager netplan interop issue

doc/rtd/reference/modules.rst

@@ -64,6 +64,8 @@ Modules
    :template: modules.tmpl
 .. datatemplate:yaml:: ../../module-docs/cc_mounts/data.yaml
    :template: modules.tmpl
+.. datatemplate:yaml:: ../../module-docs/cc_netplan_nm_patch/data.yaml
+   :template: modules.tmpl
 .. datatemplate:yaml:: ../../module-docs/cc_ntp/data.yaml
    :template: modules.tmpl
 .. datatemplate:yaml:: ../../module-docs/cc_package_update_upgrade_install/data.yaml

tests/unittests/config/test_cc_netplan_nm_patch.py

@@ -0,0 +1,9 @@
+# This file is part of cloud-init. See LICENSE file for license information.
+
+from tests.unittests.helpers import skipUnlessJsonSchema
+
+
+@skipUnlessJsonSchema()
+class TestCCNetplanNmPatch:
+    def test_schema_validation(self):
+        pass

tests/unittests/config/test_schema.py

@@ -252,6 +252,7 @@ def test_get_schema_coalesces_known_schema(self):
             {"$ref": "#/$defs/cc_lxd"},
             {"$ref": "#/$defs/cc_mcollective"},
             {"$ref": "#/$defs/cc_mounts"},
+            {"$ref": "#/$defs/cc_netplan_nm_patch"},
             {"$ref": "#/$defs/cc_ntp"},
             {"$ref": "#/$defs/cc_package_update_upgrade_install"},
             {"$ref": "#/$defs/cc_phone_home"},