I am trying to get php connecting to kafka all within a docker container.

kafka php lib - https://github.com/arnaud-lb/php-rdkafka/

kafka docker container - https://hub.docker.com/r/wurstmeister/kafka/

Everything is building and running ok, but when I try to connect with the PHP producer, I get the following:

httpd_1   | %3|1490816385.542|FAIL|rdkafka#producer-1| [thrd:kafka:9092/bootstrap]: kafka:9092/bootstrap: Failed to resolve 'kafka:9092': Name or service not known
httpd_1   | %3|1490816385.543|ERROR|rdkafka#producer-1| [thrd:kafka:9092/bootstrap]: kafka:9092/bootstrap: Failed to resolve 'kafka:9092': Name or service not known
httpd_1   | %3|1490816385.543|ERROR|rdkafka#producer-1| [thrd:kafka:9092/bootstrap]: 1/1 brokers are down

I am using the following in PHP

    $rk = new RdKafka\Producer();
    $rk->setLogLevel(LOG_DEBUG);
    $rk->addBrokers("kafka");

    $topicConf = new RdKafka\TopicConf();
    $topicConf->set("message.timeout.ms", 1000);
    $topic = $rk->newTopic("DEV", $topicConf);

    $topic->produce(RD_KAFKA_PARTITION_UA, 0, "Message");

    $rk->poll(1000);
    $kafkaConf = new RdKafka\Conf();
    $kafkaConf->setErrorCb(function ($rk, $err, $reason) {
        printf("Kafka error: %s (reason: %s)\n", rd_kafka_err2str($err), $reason);
    });
    $kafkaConf->setDrMsgCb(function ($rk, $message) {
        if ($message->err) {
            print_r($message);
        } else {
            print_r("ok");
        }
    });

I've played around, trying to set the host IP in both the docker-compose.yml and the PHP code, but no joy. I also had connection refused but I don't know if thats better or worse?

If it helps, my docker-compose.yml

httpd:
  build: .
  ports:
  - 8180:80
  volumes:
  - ~/www:/var/www/html
zookeeper:
  image: wurstmeister/zookeeper
  ports:
  - "2181:2181"
kafka:
  build: ~/kafka-docker/.
  links:
  - zookeeper
  ports:
  - "9092:9092"
  environment:
    KAFKA_ADVERTISED_HOST_NAME: kafka
    KAFKA_ADVERTISED_PORT: 9092
    KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
  volumes:
  - /var/run/docker.sock:/var/run/docker.sock

• PHP version: 7.0.17

• librdkafka version: 0.9.5.0

• php-rdkafka version: 2.0.1

My question: Any idea how I can connect to kafka successfully from php?