Kafka Error connecting to node ubuntukafka:9092 (id: 0 rack: null) (org.apache.kafka.clients.NetworkClient) java.net.UnknownHostException:

Codejoy :

I have two servers on VirtualBox guests each ubuntu. I can SSH from my main machine to both, and between the two so they all have the natnetwork.

I ran on one server kafka as described here:

https://kafka.apache.org/quickstart

So I brought up singlenode zookeper Kafka then started. I added the test topic. (All on MachineA . 10.75.1.247)

I am trying to list the topics on that node from another machine:

bin/kafka-topics.sh --list --bootstrap-server 10.75.1.247:9092

from MachineB (10.75.1.2)

doing that, causes the error over and over:

[2019-09-16 23:57:07,864] WARN [AdminClient clientId=adminclient-1] Error connecting to node ubuntukafka:9092 (id: 0 rack: null) (org.apache.kafka.clients.NetworkClient)
java.net.UnknownHostException: ubuntukafka
    at java.base/java.net.InetAddress$CachedAddresses.get(InetAddress.java:797)
    at java.base/java.net.InetAddress.getAllByName0(InetAddress.java:1505)
    at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1364)
    at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1298)
    at org.apache.kafka.clients.ClientUtils.resolve(ClientUtils.java:104)
    at org.apache.kafka.clients.ClusterConnectionStates$NodeConnectionState.currentAddress(ClusterConnectionStates.java:403)
    at org.apache.kafka.clients.ClusterConnectionStates$NodeConnectionState.access$200(ClusterConnectionStates.java:363)
    at org.apache.kafka.clients.ClusterConnectionStates.currentAddress(ClusterConnectionStates.java:151)
    at org.apache.kafka.clients.NetworkClient.initiateConnect(NetworkClient.java:943)
    at org.apache.kafka.clients.NetworkClient.ready(NetworkClient.java:288)
    at org.apache.kafka.clients.admin.KafkaAdminClient$AdminClientRunnable.sendEligibleCalls(KafkaAdminClient.java:925)
    at org.apache.kafka.clients.admin.KafkaAdminClient$AdminClientRunnable.run(KafkaAdminClient.java:1140)
    at java.base/java.lang.Thread.run(Thread.java:834)

it does resolve the name (says ubuntukafka instead of ubuntukafkanode) but fails.

What am I missing? Am I using kafka wrong? I thought I could have a nice kafka server where all my other servers with data can produce information too. Then many other consumers can read the information from?

Ultimately what I wanted to test was if I could send messages to my kafka server:

bin/kafka-console-producer.sh --broker-list 10.75.1.247:9092 --topic test

And even then use python later to produce messages to the server.

from kafka import KafkaProducer

producer = KafkaProducer(bootstrap_servers='10.75.1.247:9092')
for _ in range(100):
    try:
        producer.send('test', b'some_message_bytes')
    except:
        print('doh')

cricket_007 :

Generally, seems your hostnames aren't resolvable. Does ping ubuntukafka work? If not, then you'll need to adjust what you're making Kafka return via advertised.listeners to be the external IP rather than the hostname

listeners=PLAINTEXT://:9092
advertised.listeners=PLAINTEXT://10.75.1.247:9092