jahstreet commented on code in PR #2013:
URL:
https://github.com/apache/cassandra-java-driver/pull/2013#discussion_r1953990634
##########
manual/core/address_resolution/README.md:
##########
@@ -118,6 +118,52 @@ datastax-java-driver.advanced.address-translator.class =
com.mycompany.MyAddress
Note: the contact points provided while creating the `CqlSession` are not
translated, only addresses
retrieved from or sent by Cassandra nodes are.
+### Fixed proxy hostname
+
+If your client applications access Cassandra through some kind of proxy (eg.
with AWS PrivateLink when all Cassandra
+nodes are exposed via one hostname pointing to AWS Endpoint), you can
configure driver with
+`FixedHostNameAddressTranslator` to always translate all node addresses to
that same proxy hostname, no matter what IP
+address a node has but still using its native transport port.
+
+To use it, specify the following in the [configuration](../configuration):
+
+```
+datastax-java-driver.advanced.address-translator.class =
FixedHostNameAddressTranslator
+advertised-hostname = proxyhostname
+```
+
+### Fixed proxy hostname per subnet
+
+When running Cassandra in a private network and accessing it from outside of
that private network via some kind of
+proxy, we have an option to use `FixedHostNameAddressTranslator`. But for
multi-datacenter Cassandra deployments, we
+want to have more control over routing queries to a specific datacenter (eg.
for optimizing latencies), which requires
+setting up a separate proxy per datacenter.
+
+Normally, each Cassandra datacenter nodes are deployed to a separate subnet to
support internode communications in the
+cluster and avoid IP addresses collisions. So when Cassandra broadcasts its
nodes IP addresses, we can determine which
+datacenter that node belongs to by checking its IP address against the given
datacenter subnet.
+
+For such scenarios you can use `SubnetAddressTranslator` to translate node IPs
to the datacenter proxy address
+associated with it.
+
+To use it, specify the following in the [configuration](../configuration):
+```
+datastax-java-driver.advanced.address-translator {
+ class = SubnetAddressTranslator
+ subnet-addresses {
+ "100.64.0.0/15" = "cassandra.datacenter1.com:9042"
+ "100.66.0.0/15" = "cassandra.datacenter2.com" # port defaults to 9042 if
not specified
+ # IPv6 example:
+ # "::ffff:6440:0/111" = "cassandra.datacenter1.com:9042"
+ # "::ffff:6442:0/111" = "cassandra.datacenter2.com" # port defaults to
9042 if not specified
+ }
+ # Optional. When configured, addresses not matching the configured subnets
are translated to it. Port defaults to 9042 if not specified.
+ default-address = "cassandra.datacenter1.com:9042"
+}
+```
+
+Such setup is common for running Cassandra on Kubernetes with
[k8ssandra](https://docs.k8ssandra.io/).
Review Comment:
Right!
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