feature(sct): add support for using dns names in cluster

We want to test if Scylla works with dns names instead of IP addresses.

Adding proper methods and conditions in various places according to test
configuration.

sdcm/cluster.py

@@ -251,6 +251,7 @@ def __init__(self, name, parent_cluster, ssh_login_info=None, base_logdir=None,
 
         self.remoter: Optional[RemoteCmdRunnerBase] = None
 
+        self._use_dns_names: bool = parent_cluster.params.get('use_dns_names') or False
         self._spot_monitoring_thread = None
         self._journal_thread = None
         self._docker_log_process = None
@@ -803,6 +804,14 @@ def public_ip_address(self) -> Optional[str]:
             self._public_ip_address_cached = self._get_public_ip_address()
         return self._public_ip_address_cached
 
+    @property
+    def public_dns_name(self) -> str:
+        return self.name
+
+    @property
+    def private_dns_name(self) -> str:
+        return self.name
+
     def _get_public_ip_address(self) -> Optional[str]:
         public_ips, _ = self._refresh_instance_state()
         if public_ips:
@@ -894,6 +903,8 @@ def scylla_listen_address(self) -> str:
 
         Use it for localhost connections (e.g., cqlsh)
         """
+        if self._use_dns_names:
+            return self.private_dns_name
         return self.ip_address
 
     @property
@@ -3951,7 +3962,10 @@ def set_seeds(self, wait_for_timeout=300, first_only=False):
 
     @property
     def seed_nodes_ips(self):
-        seed_nodes_ips = [node.ip_address for node in self.nodes if node.is_seed]
+        if self.params.get('use_dns_names'):
+            seed_nodes_ips = [node.private_dns_name for node in self.nodes if node.is_seed]
+        else:
+            seed_nodes_ips = [node.ip_address for node in self.nodes if node.is_seed]
         assert seed_nodes_ips, "We should have at least one selected seed by now"
         return seed_nodes_ips
 

sdcm/cluster_aws.py

@@ -513,6 +513,18 @@ def external_address(self):
         else:
             return self._instance.private_ip_address
 
+    @cached_property
+    def public_dns_name(self) -> str:
+        result = self.remoter.run(
+            'curl http://169.254.169.254/latest/meta-data/public-hostname', verbose=False)
+        return result.stdout.strip()
+
+    @cached_property
+    def private_dns_name(self) -> str:
+        result = self.remoter.run(
+            'curl http://169.254.169.254/latest/meta-data/local-hostname', verbose=False)
+        return result.stdout.strip()
+
     def _get_public_ip_address(self) -> Optional[str]:
         return self._instance.public_ip_address
 

sdcm/provision/scylla_yaml/node_builder.py

@@ -56,6 +56,8 @@ def seed_provider(self) -> Optional[List[SeedProvider]]:
 
     @property
     def listen_address(self) -> Optional[str]:
+        if self.params.get('use_dns_names'):
+            return self.node.private_dns_name
         if self._is_ip_ssh_connections_ipv6:
             return self._ipv6_ip_address
         if self.params.get('extra_network_interface'):
@@ -65,6 +67,8 @@ def listen_address(self) -> Optional[str]:
 
     @property
     def rpc_address(self) -> Optional[str]:
+        if self.params.get('use_dns_names'):
+            return self.node.private_dns_name
         if self._is_ip_ssh_connections_ipv6:
             return self._ipv6_ip_address
         if self.params.get('extra_network_interface'):
@@ -74,6 +78,8 @@ def rpc_address(self) -> Optional[str]:
 
     @property
     def broadcast_rpc_address(self) -> Optional[str]:
+        if self.params.get('use_dns_names'):
+            return self.node.private_dns_name
         if self._is_ip_ssh_connections_ipv6:
             return self._ipv6_ip_address
         if self.params.get('extra_network_interface'):

sdcm/sct_config.py

@@ -1481,6 +1481,9 @@ class SCTConfiguration(dict):
              help="""Forces GossipingPropertyFileSnitch (regardless `endpoint_snitch`) to simulate racks.
              Provide number of racks to simulate."""),
 
+        dict(name="use_dns_names", env="SCT_USE_DNS_NAMES", type=boolean,
+             help="""Use dns names instead of ip addresses for nodes in cluster"""),
+
     ]
 
     required_params = ['cluster_backend', 'test_duration', 'n_db_nodes', 'n_loaders', 'use_preinstalled_scylla',

test-cases/longevity/longevity-mini-test-1h.yaml

@@ -1,5 +1,5 @@
-test_duration: 180
-stress_cmd: ["cassandra-stress write cl=QUORUM duration=90m -schema 'replication(strategy=NetworkTopologyStrategy,replication_factor=3)' -mode cql3 native -rate threads=50 -pop seq=1..10000000 -log interval=5"]
+test_duration: 1000
+stress_cmd: ["cassandra-stress write cl=QUORUM duration=900m -schema 'replication(strategy=NetworkTopologyStrategy,replication_factor=3)' -mode cql3 native -rate threads=2 -pop seq=1..10000000 -log interval=5"]
 
 n_db_nodes: 4
 n_loaders: 1
@@ -9,8 +9,11 @@ instance_type_db: 'i4i.large'
 
 nemesis_class_name: 'SisyphusMonkey'
 nemesis_interval: 1
+nemesis_multiply_factor: 1
+use_dns_names: true
+
 
 user_prefix: 'longevity-mini-test'
 space_node_threshold: 6442
 
-append_scylla_args: '--memory 4G --blocked-reactor-notify-ms 25 --abort-on-lsa-bad-alloc 1 --abort-on-seastar-bad-alloc --abort-on-internal-error 1 --abort-on-ebadf 1 --enable-sstable-key-validation 1'
+append_scylla_args: ' --blocked-reactor-notify-ms 25 --abort-on-lsa-bad-alloc 1 --abort-on-seastar-bad-alloc --abort-on-internal-error 1 --abort-on-ebadf 1 --enable-sstable-key-validation 1'