[relates #4259] Refactor Kudu testcontainer

diff --git a/integration-tests/kudu/pom.xml b/integration-tests/kudu/pom.xml
index 173254b..6252788 100644
--- a/integration-tests/kudu/pom.xml
+++ b/integration-tests/kudu/pom.xml
@@ -30,13 +30,6 @@
     <name>Camel Quarkus :: Integration Tests :: Kudu</name>
     <description>Integration tests for Camel Quarkus Kudu extension</description>
 
-    <properties>
-        <!-- This is to allow the "deep reflection" we do in KuduInfrastructureTestHelper -->
-        <opens>java.base/java.net=ALL-UNNAMED</opens>
-        <argLine>--add-opens ${opens}</argLine>
-        <quarkus.native.additional-build-args>-J--add-opens=${opens}</quarkus.native.additional-build-args>
-    </properties>
-
     <dependencies>
          <dependency>
             <groupId>io.quarkus</groupId>
diff --git a/integration-tests/kudu/src/main/java/org/apache/camel/quarkus/component/kudu/it/KuduInfrastructureTestHelper.java b/integration-tests/kudu/src/main/java/org/apache/camel/quarkus/component/kudu/it/KuduInfrastructureTestHelper.java
deleted file mode 100644
index fcf34ec..0000000
--- a/integration-tests/kudu/src/main/java/org/apache/camel/quarkus/component/kudu/it/KuduInfrastructureTestHelper.java
+++ /dev/null
@@ -1,98 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.apache.camel.quarkus.component.kudu.it;
-
-import java.lang.reflect.Field;
-import java.lang.reflect.Method;
-import java.net.InetAddress;
-import java.util.concurrent.ConcurrentHashMap;
-
-import io.quarkus.runtime.StartupEvent;
-import jakarta.enterprise.context.ApplicationScoped;
-import jakarta.enterprise.event.Observes;
-import org.eclipse.microprofile.config.ConfigProvider;
-import org.jboss.logging.Logger;
-
-/**
- * In order to run Kudu integration tests, {@code KuduTest} and {@code KuduIT} should have access to:
- * 1) A Kudu master server needed to create a table and also to obtain the host/port of the associated tablet server
- * 2) A Kudu tablet server needed to insert and scan records
- *
- * As such, one solution could be to use a custom setup where Kudu servers run on the same network than integration
- * tests. Please note that Kudu servers are not able to run on Windows machine.
- * Another solution could be to use the container based setup where Kudu servers are managed by
- * {@code KuduTestResource}.
- *
- * A) How to run integration tests against a custom setup (advised when not running on top of OpenJDK):
- * Install Kudu master and tablet servers on the same network than integration tests.
- * Configure "camel.kudu.test.master.rpc-authority" in "application.properties", for instance:
- * camel.kudu.test.master.rpc-authority=kudu-master-hostname:7051
- * Run integration tests with mvn clean integration-test -P native
- *
- * B) How to run integration tests against the container based setup:
- * The container based setup should run out of the box as {@code KuduTestResource} runs master and tablet server
- * containers in a shared network.
- * Simply run integration tests with mvn clean integration-test -P native
- * Note that the test harness is NOT guaranteed to work when NOT running on top of OpenJDK.
- *
- * Troubleshooting the container based setup:
- * If a message like "Unknown host kudu-tserver" is issued, it may be that
- * {@link KuduInfrastructureTestHelper#overrideTabletServerHostnameResolution()}
- * is not working. Please try to manually override the tablet server hostname resolution on your Operating System.
- * For instance, adding an entry in /etc/hosts file like: "127.0.0.1 kudu-tserver"
- *
- * If a message like "Not enough live tablet server" is issued, it may be that the shared network setup by
- * {@code KuduTestResource} is not working. In this case please refer to links below for a possible workaround:
- * <a href="https://github.com/apache/camel-quarkus/issues/1206">
- * <a href="https://github.com/moby/moby/issues/32138">
- */
-@ApplicationScoped
-public class KuduInfrastructureTestHelper {
-
-    static final String KUDU_TABLET_NETWORK_ALIAS = "kudu-tserver";
-    static final String DOCKER_HOST = "docker.host";
-    private static final Logger LOG = Logger.getLogger(KuduInfrastructureTestHelper.class);
-
-    void onStart(@Observes StartupEvent ev) {
-        LOG.info("Attempting to override the kudu tablet server hostname resolution on application startup");
-        KuduInfrastructureTestHelper.overrideTabletServerHostnameResolution();
-    }
-
-    public static void overrideTabletServerHostnameResolution() {
-        try {
-            // Warm up the InetAddress cache
-            String dockerHost = ConfigProvider.getConfig().getValue("docker.host", String.class);
-            String tabletServerHostName = dockerHost.equals("localhost") || dockerHost.equals("127.0.0.1") ? "localhost"
-                    : KUDU_TABLET_NETWORK_ALIAS;
-            InetAddress.getByName(tabletServerHostName);
-            final Field cacheField = InetAddress.class.getDeclaredField("cache");
-            cacheField.setAccessible(true);
-            final Object cache = cacheField.get(null);
-            final Method get = ConcurrentHashMap.class.getMethod("get", Object.class);
-            final Object cachedAddresses = get.invoke(cache, tabletServerHostName);
-            if (cachedAddresses == null) {
-                throw new IllegalStateException("Unable to resolve host %s. Please add a host entry for %s %s"
-                        .formatted(tabletServerHostName, dockerHost, tabletServerHostName));
-            }
-
-            final Method put = ConcurrentHashMap.class.getMethod("put", Object.class, Object.class);
-            put.invoke(cache, KUDU_TABLET_NETWORK_ALIAS, cachedAddresses);
-        } catch (Exception e) {
-            throw new IllegalStateException("Failed to apply kudu tablet server hostname override", e);
-        }
-    }
-}
diff --git a/integration-tests/kudu/src/test/java/org/apache/camel/quarkus/component/kudu/it/KuduTestResource.java b/integration-tests/kudu/src/test/java/org/apache/camel/quarkus/component/kudu/it/KuduTestResource.java
index d84f24d..9566359 100644
--- a/integration-tests/kudu/src/test/java/org/apache/camel/quarkus/component/kudu/it/KuduTestResource.java
+++ b/integration-tests/kudu/src/test/java/org/apache/camel/quarkus/component/kudu/it/KuduTestResource.java
@@ -17,6 +17,9 @@
 
 package org.apache.camel.quarkus.component.kudu.it;
 
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.util.Enumeration;
 import java.util.Map;
 import java.util.function.Consumer;
 
@@ -35,10 +38,11 @@
 import org.testcontainers.containers.output.Slf4jLogConsumer;
 import org.testcontainers.containers.wait.strategy.Wait;
 
-import static org.apache.camel.quarkus.component.kudu.it.KuduInfrastructureTestHelper.DOCKER_HOST;
-import static org.apache.camel.quarkus.component.kudu.it.KuduInfrastructureTestHelper.KUDU_TABLET_NETWORK_ALIAS;
 import static org.apache.camel.quarkus.component.kudu.it.KuduRoute.KUDU_AUTHORITY_CONFIG_KEY;
 
+/**
+ * Based on https://github.com/apache/kudu/blob/master/docker/quickstart.yml.
+ */
 public class KuduTestResource implements QuarkusTestResourceLifecycleManager {
     private static final Logger LOG = LoggerFactory.getLogger(KuduTestResource.class);
     private static final int KUDU_MASTER_RPC_PORT = 7051;
@@ -47,6 +51,7 @@
     private static final int KUDU_TABLET_HTTP_PORT = 8050;
     private static final String KUDU_IMAGE = ConfigProvider.getConfig().getValue("kudu.container.image", String.class);
     private static final String KUDU_MASTER_NETWORK_ALIAS = "kudu-master";
+    private static final String KUDU_TABLET_NETWORK_ALIAS = "kudu-tserver";
 
     private GenericContainer<?> masterContainer;
     private GenericContainer<?> tabletContainer;
@@ -54,11 +59,17 @@
     @Override
     public Map<String, String> start() {
         Network kuduNetwork = Network.newNetwork();
+        final String advertisingIpAddress = getAdvertisingIpAddress();
+        LOG.info("Advertising IP address: {}", advertisingIpAddress);
 
         // Setup the Kudu master server container
         masterContainer = new GenericContainer<>(KUDU_IMAGE)
                 .withCommand("master")
-                .withEnv("MASTER_ARGS", "--unlock_unsafe_flags=true")
+                .withEnv("MASTER_ARGS",
+                        "--unlock_unsafe_flags=true " +
+                        // we must advertise host IP address, otherwise Kudu client receives address internal to Docker container
+                                "--rpc_advertised_addresses=%s:%s".formatted(advertisingIpAddress, KUDU_MASTER_RPC_PORT))
+                .withEnv("KUDU_MASTERS", KUDU_MASTER_NETWORK_ALIAS)
                 .withExposedPorts(KUDU_MASTER_RPC_PORT, KUDU_MASTER_HTTP_PORT)
                 .withNetwork(kuduNetwork)
                 .withNetworkAliases(KUDU_MASTER_NETWORK_ALIAS)
@@ -67,6 +78,8 @@
         masterContainer.start();
 
         // Force host name and port, so that the tablet container is accessible from KuduResource, KuduTest and KuduIT.
+        // It basically forces to use fixed ports, instead of dynamic, so we can advertise them and use them externally.
+        // See https://github.com/testcontainers/testcontainers-java/issues/3967 for more context.
         Consumer<CreateContainerCmd> consumer = cmd -> {
             Ports portBindings = new Ports();
             portBindings.bind(ExposedPort.tcp(KUDU_TABLET_RPC_PORT), Ports.Binding.bindPort(KUDU_TABLET_RPC_PORT));
@@ -80,7 +93,10 @@
         // Setup the Kudu tablet server container
         tabletContainer = new GenericContainer<>(KUDU_IMAGE)
                 .withCommand("tserver")
-                .withEnv("TSERVER_ARGS", "--unlock_unsafe_flags=true")
+                .withEnv("TSERVER_ARGS",
+                        "--unlock_unsafe_flags=true " +
+                        // we must advertise host IP address, otherwise Kudu client receives address internal to Docker container
+                                "--rpc_advertised_addresses=%s:%s".formatted(advertisingIpAddress, KUDU_TABLET_RPC_PORT))
                 .withEnv("KUDU_MASTERS", KUDU_MASTER_NETWORK_ALIAS)
                 .withExposedPorts(KUDU_TABLET_RPC_PORT, KUDU_TABLET_HTTP_PORT)
                 .withNetwork(kuduNetwork)
@@ -106,8 +122,7 @@
         LOG.info("Kudu tablet server HTTP accessible at " + tServerHttpAuthority);
 
         return CollectionHelper.mapOf(
-                KUDU_AUTHORITY_CONFIG_KEY, masterRpcAuthority,
-                DOCKER_HOST, DockerClientFactory.instance().dockerHostIpAddress());
+                KUDU_AUTHORITY_CONFIG_KEY, masterRpcAuthority);
     }
 
     @Override
@@ -123,4 +138,48 @@
             LOG.error("An issue occurred while stopping the KuduTestResource", ex);
         }
     }
+
+    public String getRealHostIpAddress() {
+        try {
+            Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
+            while (interfaces.hasMoreElements()) {
+                NetworkInterface iface = interfaces.nextElement();
+
+                // skip loopback and non-active interfaces
+                if (iface.isLoopback() || !iface.isUp()) {
+                    continue;
+                }
+
+                // skip virtual/docker interfaces (they often starts with "docker" or "br-"
+                String name = iface.getName();
+                if (name.startsWith("docker") || name.startsWith("br-")) {
+                    continue;
+                }
+
+                Enumeration<InetAddress> addresses = iface.getInetAddresses();
+                while (addresses.hasMoreElements()) {
+                    InetAddress addr = addresses.nextElement();
+
+                    // only IPv4 and host address (not link-local addresses)
+                    if (addr instanceof java.net.Inet4Address && !addr.isLinkLocalAddress()) {
+                        return addr.getHostAddress();
+                    }
+                }
+            }
+            return InetAddress.getLocalHost().getHostAddress();
+        } catch (Exception e) {
+            throw new RuntimeException("Error while getting host ip address", e);
+        }
+    }
+
+    public String getAdvertisingIpAddress() {
+        LOG.info("DOCKER_HOST is set to {}", System.getenv("DOCKER_HOST"));
+        String dockerHostIpAddress = DockerClientFactory.instance().dockerHostIpAddress();
+        if ("localhost".equals(dockerHostIpAddress)) {
+            LOG.info("Docker is running on local host - going to resolve real IP of the host");
+            return getRealHostIpAddress();
+        }
+        // else Docker is running remotely and thus use the IP of remote host.
+        return dockerHostIpAddress;
+    }
 }