I'd like to have a simple Cassandra/Scylla cluster with two nodes, rf 2 so they both contain the same data. I want to expose one node to the internet (temporarily) behind NAT. The router has a dynamic IP which is resolved by a dynDNS on, let's say, domain.my.
The idea is quite simple: an app with the Java Driver connects to the back-end app through domain:port, which NAT routes to c1. Node c2 works as backup and on internal network workloads.
I set it up and it works quite well, but the JavaDriver retrieves the internal topology and tries to connect also to node2 on x.x.x.02, which is obviously incorrect.
DataStax Java driver for Apache Cassandra(R) (com.datastax.oss:java-driver-core) version 4.17.0
Adding handler to invalidate cached prepared statements on type changes
Using native clock for microsecond precision
[s0|/x.x.x.2:9042] Error while opening new channel (ConnectionInitException: [s0|connecting...] Protocol initialization request, step 1 (STARTUP {CQL_VERSION=3.0.0, DRIVER_NAME=DataStax Java driver for Apache Cassandra(R), DRIVER_VERSION=4.17.0, CLIENT_ID=fa6fade1-58ca-4d73-b85b-2f316abf9d02}): failed to send request (java.nio.channels.NotYetConnectedException))
Connected to cluster: Uzz, with session: s0
Datacenter: datacenter1; Host: domain.my/<unresolved>:9042; Rack: rack1
Datacenter: datacenter1; Host: /x.x.x.2:9042; Rack: rack1
Is there any way to prevent that? I have explored to use an AddressTranslator to map both addresses to the public address but this does not work well with the key space:
Unexpected error while refreshing token map, keeping previous version (IllegalArgumentException: Multiple entries with same key: Murmur3Token(-107948562044971185)=Node(endPoint=domain.my/<unresolved>:9042, hostId=15450683-e34b-475d-a393-ad25611398d8, hashCode=38b03e88) and Murmur3Token(-107948562044971185)=Node(endPoint=domain.my/<unresolved>:9042, hostId=15450683-e34b-475d-a393-ad25611398d8, hashCode=38b03e88))
Is this use case doable at all? Is there any better way?
nodetool status
Datacenter: datacenter1
=======================
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns Host ID Rack
UN x.x.x.51 34.44 GB 256 ? 15450683-e34b-475d-a393-ad25611398d8 rack1
UN x.x.x.100 34.5 GB 256 ? 6cad2ba2-b22e-4947-a952-dc65c616a08f rack1
Note: Non-system keyspaces don't have the same replication settings, effective ownership information is meaningless
application.properties
#
# DataStax Java Driver for Cassandra configuration file
datastax-java-driver.basic.config-reload-interval = 0
datastax-java-driver.advanced.protocol.version = V4
datastax-java-driver.advanced.netty.daemon = true
datastax-java-driver.advanced.metadata.schema.enabled = false
datastax-java-driver.advanced.address-translator.class = ste.uzz.store.CassandraAddressTranslator
datastax-java-driver.advanced.address-translator.public-address = uzz.fornari.net