container: T6701: add support to disable container network DNS support (#4052)

Add ability to set the container network with a disable-dns setting to disable
the DNS plugin that is on be default.

  set container network <network> no-name-server

(cherry picked from commit 1d5625d572cc25a9d53247b7c41177f17845b052)

Co-authored-by: Dave Vogel <dave.vogel@fullpower.com>

3 files changed, 26 insertions, 0 deletions

diff --git a/interface-definitions/container.xml.in b/interface-definitions/container.xml.in
index 6ea44a6d4..3dd1b3249 100644
--- a/interface-definitions/container.xml.in
+++ b/interface-definitions/container.xml.in
@@ -519,6 +519,12 @@
               <multi/>
             </properties>
           </leafNode>
+          <leafNode name="no-name-server">
+            <properties>
+              <help>Disable Domain Name System (DNS) plugin for this network</help>
+              <valueless/>
+            </properties>
+          </leafNode>
           #include <include/interface/vrf.xml.i>
         </children>
       </tagNode>
diff --git a/smoketest/scripts/cli/test_container.py b/smoketest/scripts/cli/test_container.py
index 5e33eba40..c03b9eb44 100755
--- a/smoketest/scripts/cli/test_container.py
+++ b/smoketest/scripts/cli/test_container.py
@@ -208,6 +208,22 @@ class TestContainer(VyOSUnitTestSHIM.TestCase):
             self.assertEqual(c['NetworkSettings']['Networks'][net_name]['Gateway']          , str(ip_interface(prefix4).ip + 1))
             self.assertEqual(c['NetworkSettings']['Networks'][net_name]['IPAddress']        , str(ip_interface(prefix4).ip + ii))
 
+    def test_no_name_server(self):
+        prefix = '192.0.2.0/24'
+        base_name = 'ipv4'
+        net_name = 'NET01'
+
+        self.cli_set(base_path + ['network', net_name, 'prefix', prefix])
+        self.cli_set(base_path + ['network', net_name, 'no-name-server'])
+
+        name = f'{base_name}-2'
+        self.cli_set(base_path + ['name', name, 'image', cont_image])
+        self.cli_set(base_path + ['name', name, 'network', net_name, 'address', str(ip_interface(prefix).ip + 2)])
+        self.cli_commit()
+
+        n = cmd_to_json(f'sudo podman network inspect {net_name}')
+        self.assertEqual(n['dns_enabled'], False)
+
     def test_uid_gid(self):
         cont_name = 'uid-test'
         gid = '100'
diff --git a/src/conf_mode/container.py b/src/conf_mode/container.py
index ded370a7a..14387cbbf 100755
--- a/src/conf_mode/container.py
+++ b/src/conf_mode/container.py
@@ -421,6 +421,10 @@ def generate(container):
                     'driver': 'host-local'
                 }
             }
+
+            if 'no_name_server' in network_config:
+                tmp['dns_enabled'] = False
+
             for prefix in network_config['prefix']:
                 net = {'subnet': prefix, 'gateway': inc_ip(prefix, 1)}
                 tmp['subnets'].append(net)