net: Allow for NetworkManager configuration

In cases where the config json specifies nameserver entries,
if there are interfaces configured to use dhcp, NetworkManager,
if enabled, will clobber the /etc/resolv.conf that cloud-init
has produced, which can break dns. If there are no interfaces
configured to use dhcp, NetworkManager could clobber
/etc/resolv.conf with an empty file.

This patch adds a mechanism for dropping additional configuration
into /etc/NetworkManager/conf.d/ and disables management of
/etc/resolv.conf by NetworkManager when nameserver information is
provided in the config.

LP: #1693251

Signed-off-by: Ryan McCabe <rmccabe@redhat.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/cloudinit/distros/parsers/networkmanager_conf.py b/cloudinit/distros/parsers/networkmanager_conf.py
new file mode 100644
index 00000000..ac51f122
--- /dev/null
+++ b/cloudinit/distros/parsers/networkmanager_conf.py
@@ -0,0 +1,23 @@
+# Copyright (C) 2017 Red Hat, Inc.
+#
+# Author: Ryan McCabe <rmccabe@redhat.com>
+#
+# This file is part of cloud-init. See LICENSE file for license information.
+
+import configobj
+
+# This module is used to set additional NetworkManager configuration
+# in /etc/NetworkManager/conf.d
+#
+
+
+class NetworkManagerConf(configobj.ConfigObj):
+    def __init__(self, contents):
+        configobj.ConfigObj.__init__(self, contents,
+                                     interpolation=False,
+                                     write_empty_values=False)
+
+    def set_section_keypair(self, section_name, key, value):
+        if section_name not in self.sections:
+            self.main[section_name] = {}
+        self.main[section_name] = {key: value}