Remove DNS configuration from minigraph schema (sonic-net#15727)

#### Why I did it
We should not modify minigraph schema.

#### How I did it
Update minigraph.py and remove unit test.

#### How to verify it
Run sonic-config-engine unit test.

Author: ganglyu

src/sonic-config-engine/minigraph.py

@@ -993,7 +993,6 @@ def parse_meta(meta, hname):
     dhcp_servers = []
     dhcpv6_servers = []
     ntp_servers = []
-    dns_nameservers = []
     tacacs_servers = []
     mgmt_routes = []
     erspan_dst = []
@@ -1024,8 +1023,6 @@ def parse_meta(meta, hname):
                     dhcp_servers = value_group
                 elif name == "NtpResources":
                     ntp_servers = value_group
-                elif name == "DnsNameserverResources":
-                    dns_nameservers = value_group
                 elif name == "SyslogResources":
                     syslog_servers = value_group
                 elif name == "TacacsServer":
@@ -1064,7 +1061,7 @@ def parse_meta(meta, hname):
                     qos_profile = value
                 elif name == "RackMgmtMap":
                     rack_mgmt_map = value
-    return syslog_servers, dhcp_servers, dhcpv6_servers, ntp_servers, dns_nameservers, tacacs_servers, mgmt_routes, erspan_dst, deployment_id, region, cloudtype, resource_type, downstream_subrole, switch_id, switch_type, max_cores, kube_data, macsec_profile, downstream_redundancy_types, redundancy_type, qos_profile, rack_mgmt_map
+    return syslog_servers, dhcp_servers, dhcpv6_servers, ntp_servers, tacacs_servers, mgmt_routes, erspan_dst, deployment_id, region, cloudtype, resource_type, downstream_subrole, switch_id, switch_type, max_cores, kube_data, macsec_profile, downstream_redundancy_types, redundancy_type, qos_profile, rack_mgmt_map
 
 
 def parse_linkmeta(meta, hname):
@@ -1491,7 +1488,6 @@ def parse_xml(filename, platform=None, port_config_file=None, asic_name=None, hw
     dhcp_servers = []
     dhcpv6_servers = []
     ntp_servers = []
-    dns_nameservers = []
     tacacs_servers = []
     mgmt_routes = []
     erspan_dst = []
@@ -1547,7 +1543,7 @@ def parse_xml(filename, platform=None, port_config_file=None, asic_name=None, hw
             elif child.tag == str(QName(ns, "UngDec")):
                 (u_neighbors, u_devices, _, _, _, _, _, _) = parse_png(child, hostname, None)
             elif child.tag == str(QName(ns, "MetadataDeclaration")):
-                (syslog_servers, dhcp_servers, dhcpv6_servers, ntp_servers, dns_nameservers, tacacs_servers, mgmt_routes, erspan_dst, deployment_id, region, cloudtype, resource_type, downstream_subrole, switch_id, switch_type, max_cores, kube_data, macsec_profile, downstream_redundancy_types, redundancy_type, qos_profile, rack_mgmt_map) = parse_meta(child, hostname)
+                (syslog_servers, dhcp_servers, dhcpv6_servers, ntp_servers, tacacs_servers, mgmt_routes, erspan_dst, deployment_id, region, cloudtype, resource_type, downstream_subrole, switch_id, switch_type, max_cores, kube_data, macsec_profile, downstream_redundancy_types, redundancy_type, qos_profile, rack_mgmt_map) = parse_meta(child, hostname)
             elif child.tag == str(QName(ns, "LinkMetadataDeclaration")):
                 linkmetas = parse_linkmeta(child, hostname)
             elif child.tag == str(QName(ns, "DeviceInfos")):
@@ -2003,7 +1999,6 @@ def parse_xml(filename, platform=None, port_config_file=None, asic_name=None, hw
     results['DHCP_SERVER'] = dict((item, {}) for item in dhcp_servers)
     results['DHCP_RELAY'] = dhcp_relay_table
     results['NTP_SERVER'] = dict((item, {}) for item in ntp_servers)
-    results['DNS_NAMESERVER'] = dict((item, {}) for item in dns_nameservers)
     results['TACPLUS_SERVER'] = dict((item, {'priority': '1', 'tcp_port': '49'}) for item in tacacs_servers)
     if len(acl_table_types) > 0:
         results['ACL_TABLE_TYPE'] = acl_table_types

src/sonic-config-engine/tests/multi_npu_data/sample-minigraph.xml

@@ -1425,11 +1425,6 @@
             <a:Reference i:nil="true"/>
             <a:Value>17.39.1.129;17.39.1.130</a:Value>
           </a:DeviceProperty>
-          <a:DeviceProperty>
-            <a:Name>DnsNameserverResources</a:Name>
-            <a:Reference i:nil="true"/>
-            <a:Value>1.1.1.1;8.8.8.8</a:Value>
-          </a:DeviceProperty>
           <a:DeviceProperty>
             <a:Name>SnmpResources</a:Name>
             <a:Reference i:nil="true"/>

src/sonic-config-engine/tests/simple-sample-graph-case.xml

@@ -500,12 +500,6 @@
       10.0.10.1;10.0.10.2
      </a:Value>
     </a:DeviceProperty>
-    <a:DeviceProperty>
-     <a:Name>DnsNameserverResources</a:Name>
-     <a:Value>
-      1.1.1.1;8.8.8.8
-     </a:Value>
-    </a:DeviceProperty>
     <a:DeviceProperty>
      <a:Name>SnmpResources</a:Name>
      <a:Value>

src/sonic-config-engine/tests/simple-sample-graph-metadata.xml

@@ -236,12 +236,6 @@
       10.0.10.1;10.0.10.2
      </a:Value>
     </a:DeviceProperty>
-    <a:DeviceProperty>
-     <a:Name>DnsNameserverResources</a:Name>
-     <a:Value>
-      20.2.2.2;30.3.3.3
-     </a:Value>
-    </a:DeviceProperty>
     <a:DeviceProperty>
      <a:Name>SnmpResources</a:Name>
      <a:Value>

src/sonic-config-engine/tests/test_cfggen.py

@@ -696,11 +696,6 @@ def test_metadata_ntp(self):
         output = self.run_script(argument)
         self.assertEqual(utils.to_dict(output.strip()), utils.to_dict("{'10.0.10.1': {}, '10.0.10.2': {}}"))
 
-    def test_metadata_dns_nameserver(self):
-        argument = ['-m', self.sample_graph_metadata, '-p', self.port_config, '-v', "DNS_NAMESERVER"]
-        output = self.run_script(argument)
-        self.assertEqual(utils.to_dict(output.strip()), utils.to_dict("{'20.2.2.2': {}, '30.3.3.3': {}}"))
-
     def test_minigraph_vnet(self, **kwargs):
         graph_file = kwargs.get('graph_file', self.sample_graph_simple)
         argument = ['-m', graph_file, '-p', self.port_config, '-v', "VNET"]

src/sonic-config-engine/tests/test_minigraph_case.py

@@ -277,11 +277,6 @@ def test_metadata_ntp(self):
         output = self.run_script(argument)
         self.assertEqual(output.strip(), "{'10.0.10.1': {}, '10.0.10.2': {}}")
 
-    def test_metadata_dns_nameserver(self):
-        argument = ['-m', self.sample_graph, '-p', self.port_config, '-v', "DNS_NAMESERVER"]
-        output = self.run_script(argument)
-        self.assertEqual(output.strip(), "{'1.1.1.1': {}, '8.8.8.8': {}}")
-
     def test_minigraph_vnet(self):
         argument = ['-m', self.sample_graph, '-p', self.port_config, '-v', "VNET"]
         output = self.run_script(argument)

src/sonic-config-engine/tests/test_multinpu_cfggen.py

@@ -150,17 +150,6 @@ def test_metadata_ntp(self):
             print("Log:asic{} sku {}".format(asic,output))
             self.assertDictEqual(output, {})
 
-    def test_metadata_dns_nameserver(self):
-        argument = ['-m', self.sample_graph, '-p', self.sample_port_config, '--var-json', "DNS_NAMESERVER"]
-        output = json.loads(self.run_script(argument))
-        self.assertDictEqual(output, {'1.1.1.1': {}, '8.8.8.8': {}})
-        #DNS_NAMESERVER data is present only in the host config
-        argument = ['-m', self.sample_graph, '--var-json', "DNS_NAMESERVER"]
-        for asic in range(NUM_ASIC):
-            output = json.loads(self.run_script_for_asic(argument, asic, self.port_config[asic]))
-            print("Log:asic{} sku {}".format(asic,output))
-            self.assertDictEqual(output, {})
-
     def test_mgmt_port(self):
         argument = ['-m', self.sample_graph, '-p', self.sample_port_config, '--var-json', "MGMT_PORT"]
         output = json.loads(self.run_script(argument))