$ ./tools/bin/cassandra-stress write n=10 -node 127.0.0.1:9046,127.0.0.1:9048
...
java.lang.RuntimeException: java.lang.IllegalArgumentException: Failed to add contact point: 127.0.0.1:9046
at org.apache.cassandra.stress.settings.StressSettings.getJavaDriverClient(StressSettings.java:148)
at org.apache.cassandra.stress.settings.StressSettings.getJavaDriverClient(StressSettings.java:116)
at org.apache.cassandra.stress.settings.SettingsSchema.createKeySpaces(SettingsSchema.java:66)
at org.apache.cassandra.stress.settings.StressSettings.maybeCreateKeyspaces(StressSettings.java:156)
at org.apache.cassandra.stress.StressAction.run(StressAction.java:56)
at org.apache.cassandra.stress.Stress.run(Stress.java:143)
at org.apache.cassandra.stress.Stress.main(Stress.java:62)
Caused by: java.lang.IllegalArgumentException: Failed to add contact point: 127.0.0.1:9046
at com.datastax.driver.core.Cluster$Builder.addContactPoint(Cluster.java:922)
at org.apache.cassandra.stress.util.JavaDriverClient.connect(JavaDriverClient.java:131)
at org.apache.cassandra.stress.settings.StressSettings.getJavaDriverClient(StressSettings.java:139)
... 6 more
Caused by: java.net.UnknownHostException: 127.0.0.1:9046: invalid IPv6 address
at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1341)
at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1298)
at com.datastax.driver.core.Cluster$Builder.addContactPoint(Cluster.java:919)
... 8 more