sysconfig: Correctly render dns and dns search info.

Currently when dns and dns search info is provided, it is not rendered
when outputting to sysconfig format.

This patch causes the DNS and DOMAIN lines to be written out rendering
sysconfig.

LP: #1705804

1 files changed, 15 insertions, 0 deletions

diff --git a/cloudinit/net/sysconfig.py b/cloudinit/net/sysconfig.py
index f5727969..39d89c46 100644
--- a/cloudinit/net/sysconfig.py
+++ b/cloudinit/net/sysconfig.py
@@ -7,12 +7,15 @@ import six
 
 from cloudinit.distros.parsers import networkmanager_conf
 from cloudinit.distros.parsers import resolv_conf
+from cloudinit import log as logging
 from cloudinit import util
 
 from . import renderer
 from .network_state import (
     is_ipv6_addr, net_prefix_to_ipv4_mask, subnet_is_ipv6)
 
+LOG = logging.getLogger(__name__)
+
 
 def _make_header(sep='#'):
     lines = [
@@ -347,6 +350,18 @@ class Renderer(renderer.Renderer):
                     else:
                         iface_cfg['GATEWAY'] = subnet['gateway']
 
+                if 'dns_search' in subnet:
+                    iface_cfg['DOMAIN'] = ' '.join(subnet['dns_search'])
+
+                if 'dns_nameservers' in subnet:
+                    if len(subnet['dns_nameservers']) > 3:
+                        # per resolv.conf(5) MAXNS sets this to 3.
+                        LOG.debug("%s has %d entries in dns_nameservers. "
+                                  "Only 3 are used.", iface_cfg.name,
+                                  len(subnet['dns_nameservers']))
+                    for i, k in enumerate(subnet['dns_nameservers'][:3], 1):
+                        iface_cfg['DNS' + str(i)] = k
+
     @classmethod
     def _render_subnet_routes(cls, iface_cfg, route_cfg, subnets):
         for i, subnet in enumerate(subnets, start=len(iface_cfg.children)):