Ryan McCabe has proposed merging ~rmccabe/cloud-init:bug1693251 into
cloud-init:master.
Requested reviews:
cloud-init commiters (cloud-init-dev)
Related bugs:
Bug #1693251 in cloud-init: "cloud-init should configure networkmanager to
not manage /etc/resolv.conf"
https://bugs.launchpad.net/cloud-init/+bug/1693251
For more details, see:
https://code.launchpad.net/~rmccabe/cloud-init/+git/cloud-init/+merge/325239
LP: #1693251
In cases where the config json specifies nameserver entries, NetworkManager, if
enabled, will clobber the /etc/resolv.conf that cloud-init has produced, which
can break dns. If at least one interface is configured for dhcp, you might end
up with a resolv.conf that doesn't function as intended, and if you don't have
any interfaces that get dns from dhcp, NetworkManager could clobber resolv.conf
with an empty file.
This patch adds a mechanism for dropping additional configuration into
/etc/NetworkManager/conf.d/. I figured at some point, somebody will need to set
some other keypair to stop NetworkManager from misbehaving, so I added
something for that instead of simply writing the particular 2 lines of config
to fix the resolv.conf issue.
This patch only writes out that configuration file if necessary (as opposed to
creating an empty file when there is no config needed). I wasn't sure which was
preferred, so if that's not ideal, I could write out the empty file for
consistency.
This patch will also write that config "(dns=none") out, too, for the specific
problem noted in #1693251
--
Your team cloud-init commiters is requested to review the proposed merge of
~rmccabe/cloud-init:bug1693251 into cloud-init:master.
diff --git a/cloudinit/distros/parsers/networkmanager_conf.py b/cloudinit/distros/parsers/networkmanager_conf.py
new file mode 100644
index 0000000..aa57582
--- /dev/null
+++ b/cloudinit/distros/parsers/networkmanager_conf.py
@@ -0,0 +1,25 @@
+# Copyright (C) 2017 Red Hat, Inc.
+#
+# Author: Ryan McCabe <rmcc...@redhat.com>
+#
+# This file is part of cloud-init. See LICENSE file for license information.
+
+import six
+from six import StringIO
+
+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 not section_name in self.sections:
+ self.main[section_name] = {}
+ self.main[section_name] = {key: value}
diff --git a/cloudinit/net/sysconfig.py b/cloudinit/net/sysconfig.py
index 58c5713..6659d3b 100644
--- a/cloudinit/net/sysconfig.py
+++ b/cloudinit/net/sysconfig.py
@@ -6,6 +6,7 @@ import re
import six
from cloudinit.distros.parsers import resolv_conf
+from cloudinit.distros.parsers import networkmanager_conf
from cloudinit import util
from . import renderer
@@ -252,6 +253,9 @@ class Renderer(renderer.Renderer):
self.netrules_path = config.get(
'netrules_path', 'etc/udev/rules.d/70-persistent-net.rules')
self.dns_path = config.get('dns_path', 'etc/resolv.conf')
+ nm_conf_path = 'etc/NetworkManager/conf.d/99-cloud-init.conf'
+ self.networkmanager_conf_path = config.get('networkmanager_conf_path',
+ nm_conf_path)
@classmethod
def _render_iface_shared(cls, iface, iface_cfg):
@@ -445,6 +449,20 @@ class Renderer(renderer.Renderer):
content.add_search_domain(searchdomain)
return "\n".join([_make_header(';'), str(content)])
+ @staticmethod
+ def _render_networkmanager_conf(network_state):
+ content = networkmanager_conf.NetworkManagerConf("")
+
+ # If DNS server information is provided, configure
+ # NetworkManager to not manage dns, so that /etc/resolv.conf
+ # does not get clobbered.
+ if network_state.dns_nameservers:
+ content.set_section_keypair('main', 'dns', 'none')
+
+ if len(content) == 0:
+ return None
+ return "".join([_make_header(), "\n", "\n".join(content.write()), "\n"])
+
@classmethod
def _render_bridge_interfaces(cls, network_state, iface_contents):
bridge_filter = renderer.filter_by_type('bridge')
@@ -505,6 +523,12 @@ class Renderer(renderer.Renderer):
resolv_content = self._render_dns(network_state,
existing_dns_path=dns_path)
util.write_file(dns_path, resolv_content, file_mode)
+ if self.networkmanager_conf_path:
+ nm_conf_path = util.target_path(target,
+ self.networkmanager_conf_path)
+ nm_conf_content = self._render_networkmanager_conf(network_state)
+ if nm_conf_content:
+ util.write_file(nm_conf_path, nm_conf_content, file_mode)
if self.netrules_path:
netrules_content = self._render_persistent_net(network_state)
netrules_path = util.target_path(target, self.netrules_path)
diff --git a/tests/unittests/test_net.py b/tests/unittests/test_net.py
index 0000b07..ac1a16a 100644
--- a/tests/unittests/test_net.py
+++ b/tests/unittests/test_net.py
@@ -164,6 +164,13 @@ NETMASK0=0.0.0.0
;
nameserver 172.19.0.12
""".lstrip()),
+ ('etc/NetworkManager/conf.d/99-cloud-init.conf',
+ """
+# Created by cloud-init on instance boot automatically, do not edit.
+#
+[main]
+dns = none
+""".lstrip()),
('etc/udev/rules.d/70-persistent-net.rules',
"".join(['SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ',
'ATTR{address}=="fa:16:3e:ed:9a:59", NAME="eth0"\n']))]
@@ -225,6 +232,13 @@ USERCTL=no
;
nameserver 172.19.0.12
""".lstrip()),
+ ('etc/NetworkManager/conf.d/99-cloud-init.conf',
+ """
+# Created by cloud-init on instance boot automatically, do not edit.
+#
+[main]
+dns = none
+""".lstrip()),
('etc/udev/rules.d/70-persistent-net.rules',
"".join(['SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ',
'ATTR{address}=="fa:16:3e:ed:9a:59", NAME="eth0"\n']))]
@@ -308,6 +322,13 @@ USERCTL=no
;
nameserver 172.19.0.12
""".lstrip()),
+ ('etc/NetworkManager/conf.d/99-cloud-init.conf',
+ """
+# Created by cloud-init on instance boot automatically, do not edit.
+#
+[main]
+dns = none
+""".lstrip()),
('etc/udev/rules.d/70-persistent-net.rules',
"".join(['SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ',
'ATTR{address}=="fa:16:3e:ed:9a:59", NAME="eth0"\n']))]
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