KAFKA_BROKER_ID

Author: julianladisch

docs/modules/kafka.md

@@ -56,15 +56,15 @@ Create a `KafkaContainer` to use it in your tests:
 
 ### withNetworkAliases
 
-The first alias host name defined using `withNetworkAliases` configures port 9092. Example for `kafka:9092`:
+The first alias host name defined using `withNetworkAliases` configures port 9092 on the network set by `withNetwork`. Example for `kafka:9092`:
 
 <!--codeinclude-->
 [Creating a KafkaContainer](../../modules/kafka/src/test/java/org/testcontainers/kafka/KafkaContainerTest.java) inside_block:registerAlias
 <!--/codeinclude-->
 
 This works with `org.testcontainers.kafka.KafkaContainer` and `org.testcontainers.kafka.ConfluentKafkaContainer` but not with deprecated `org.testcontainers.containers.KafkaContainer`.
 
-It only works if `withListener` is not used.
+It only works if `withListener` is not used and `KAFKA_BROKER_ID` environment variable is not set.
 
 ## Options
         

modules/kafka/src/main/java/org/testcontainers/kafka/ConfluentKafkaContainer.java

@@ -50,7 +50,7 @@ protected void configure() {
     protected void containerIsStarting(InspectContainerResponse containerInfo) {
         List<String> networkAliases = getNetworkAliases();
         String plaintextAdvertisedListener;
-        if (listeners.isEmpty() && networkAliases.size() > 1) {
+        if (!getEnvMap().containsKey("KAFKA_BROKER_ID") && listeners.isEmpty() && networkAliases.size() > 1) {
             // 0 is the random network alias generated by GenericContainer
             plaintextAdvertisedListener = "PLAINTEXT://" + networkAliases.get(1) + ":" + KafkaHelper.KAFKA_PORT;
         } else {

modules/kafka/src/main/java/org/testcontainers/kafka/KafkaContainer.java

@@ -56,7 +56,7 @@ protected void configure() {
     protected void containerIsStarting(InspectContainerResponse containerInfo) {
         List<String> networkAliases = getNetworkAliases();
         String plaintextAdvertisedListener;
-        if (listeners.isEmpty() && networkAliases.size() > 1) {
+        if (!getEnvMap().containsKey("KAFKA_BROKER_ID") && listeners.isEmpty() && networkAliases.size() > 1) {
             // 0 is the random network alias generated by GenericContainer
             plaintextAdvertisedListener = "PLAINTEXT://" + networkAliases.get(1) + ":" + KafkaHelper.KAFKA_PORT;
         } else {