Enable iburst option for NTP servers loaded from minigraph (sonic-net#19424)

Why I did it
In sonic-net#15058, the NTP server configuration was modified to add additional options, such as conditionally enabling iburst, specifying the association type, and specifying the NTP version. One side effect of this was that the iburst option which was previously always enabled now requires it to be explicitly enabled in the config_db.

Fixes sonic-net#19425.

How I did it
To restore the old behavior, when loading from minigraph, add "iburst": "true" for each NTP server loaded from minigraph.

How to verify it
Tested on a KVM setup, verified that the generated ntp.conf file had the iburst option.

Signed-off-by: Saikrishna Arcot <sarcot@microsoft.com>

Author: saiarcot895

src/sonic-config-engine/minigraph.py

@@ -2612,7 +2612,7 @@ def parse_xml(filename, platform=None, port_config_file=None, asic_name=None, hw
         results['SYSLOG_SERVER'] = dict((item, {}) for item in syslog_servers)
         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['NTP_SERVER'] = dict((item, {'iburst': 'on'}) for item in ntp_servers)
         # Set default DNS nameserver from dns.j2
         results['DNS_NAMESERVER'] = {}
         if os.environ.get("CFGGEN_UNIT_TESTING", "0") == "2":

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

@@ -696,7 +696,7 @@ def test_metadata_tacacs(self):
     def test_metadata_ntp(self):
         argument = ['-m', self.sample_graph_metadata, '-p', self.port_config, '-v', "NTP_SERVER"]
         output = self.run_script(argument)
-        self.assertEqual(utils.to_dict(output.strip()), utils.to_dict("{'10.0.10.1': {}, '10.0.10.2': {}}"))
+        self.assertEqual(utils.to_dict(output.strip()), utils.to_dict("{'10.0.10.1': {'iburst': 'on'}, '10.0.10.2': {'iburst': 'on'}}"))
 
     def test_dns_nameserver(self):
         argument = ['-m', self.sample_graph_metadata, '-p', self.port_config, '-v', "DNS_NAMESERVER"]

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

@@ -104,7 +104,7 @@ def test_ntp(self):
         argument = ['-m', self.sample_graph, '-p',
                     self.sample_port_config, '--var-json', 'NTP_SERVER']
         output = json.loads(self.run_script(argument))
-        self.assertDictEqual(output, {'17.39.1.130': {}, '17.39.1.129': {}})
+        self.assertDictEqual(output, {'17.39.1.130': {'iburst': 'on'}, '17.39.1.129': {'iburst': 'on'}})
         # NTP data is present only in the host config
         argument = ['-m', self.sample_graph, '--var-json', 'NTP_SERVER']
 
@@ -416,7 +416,7 @@ def test_ntp(self):
         argument = ['-m', self.sample_graph, '-p',
                     self.sample_port_config, '--var-json', 'NTP_SERVER']
         output = json.loads(self.run_script(argument))
-        self.assertDictEqual(output, {'17.39.1.130': {}, '17.39.1.129': {}})
+        self.assertDictEqual(output, {'17.39.1.130': {'iburst': 'on'}, '17.39.1.129': {'iburst': 'on'}})
         # NTP data is present only in the host config
         argument = ['-m', self.sample_graph, '--var-json', 'NTP_SERVER']
 
@@ -884,7 +884,7 @@ def test_ntp(self):
             '--var-json', 'NTP_SERVER'
         ]
         output = json.loads(self.run_script(argument))
-        self.assertDictEqual(output, {'17.39.1.130': {}, '17.39.1.129': {}})
+        self.assertDictEqual(output, {'17.39.1.130': {'iburst': 'on'}, '17.39.1.129': {'iburst': 'on'}})
 
 
     def test_mgmt_port(self):
@@ -1019,7 +1019,7 @@ def test_ntp(self):
             '--var-json', 'NTP_SERVER'
         ]
         output = json.loads(self.run_script(argument))
-        self.assertDictEqual(output, {'17.39.1.130': {}, '17.39.1.129': {}})
+        self.assertDictEqual(output, {'17.39.1.130': {'iburst': 'on'}, '17.39.1.129': {'iburst': 'on'}})
         # NTP data is present only in the host config
         argument = ['-m', self.sample_graph, '--var-json', 'NTP_SERVER']
 

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

@@ -283,7 +283,7 @@ def test_minigraph_mgmt_port(self):
     def test_metadata_ntp(self):
         argument = ['-m', self.sample_graph, '-p', self.port_config, '-v', "NTP_SERVER"]
         output = self.run_script(argument)
-        self.assertEqual(output.strip(), "{'10.0.10.1': {}, '10.0.10.2': {}}")
+        self.assertEqual(output.strip(), "{'10.0.10.1': {'iburst': 'on'}, '10.0.10.2': {'iburst': 'on'}}")
 
     def test_minigraph_vnet(self):
         argument = ['-m', self.sample_graph, '-p', self.port_config, '-v', "VNET"]

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

@@ -151,7 +151,7 @@ def test_metadata_tacacs(self):
     def test_metadata_ntp(self):
         argument = ['-m', self.sample_graph, '-p', self.sample_port_config, '--var-json', "NTP_SERVER"]
         output = json.loads(self.run_script(argument))
-        self.assertDictEqual(output, {'17.39.1.130': {}, '17.39.1.129': {}})
+        self.assertDictEqual(output, {'17.39.1.130': {'iburst': 'on'}, '17.39.1.129': {'iburst': 'on'}})
         #NTP data is present only in the host config
         argument = ['-m', self.sample_graph, '--var-json', "NTP_SERVER"]
         for asic in range(NUM_ASIC):