I have the same problem on windows using Kafka 1.0.0

@vkroz what version of kafka-python / kafka brokers?

Can you share the code snippet you used for confluent-kafka-python to connect?

@jeffwidman It's just 2 lines of code in Python console as shown above.

And apparently it has something to do with setup of specific cluster. When I'm trying to connect to another remote Kafka cluster it works fine.

Are there differences between the server.properties of the two clusters? I'd start by checking the listeners and advertised.listeners configs.

Here are server properties used to run 3-nodes cluster on localhost -- the one which is python client os failing to connect

https://gist.github.com/vkroz/5ee7854448fdd96ab619a7f7380fa0c2

And these config are fully operations, cluster is accessible by Java producers/consumers and all standard Kafka tools.

These look fine to me, nothing amiss. Can you share the snippet you use to connect using confluent-kafka-python? If you're running from the exact same machine with the same broker address, it's weird to me that the confluent client can connect but kafka-python can't. Are you perhaps running the confluent/java codes from a different container/VM than where you run kafka-python?

what does this show:

python -c 'import socket; print socket.getaddrinfo("localhost", 9092)'

Version 1.3.5 of this library (which is latest on pypy) only lists certain API versions 0.8.0 to 0.10.1. So unless you explicitly specify api_version to be (0, 10, 1) the client library's attempt to discover the version will cause a NoBrokersAvailable error.

an example from my code:

producer = KafkaProducer(
    bootstrap_servers=URL,
    client_id=CLIENT_ID,
    value_serializer=JsonSerializer.serialize,
    api_version=(0, 10, 1)
)

Although setting api_version may appear to fix a problem, this is a very wrong assessment:

Version 1.3.5 of this library (which is latest on pypy) only lists certain API versions 0.8.0 to 0.10.1. So unless you explicitly specify api_version to be (0, 10, 1) the client library's attempt to discover the version will cause a NoBrokersAvailable error.

The issue is not the version check, it is the TCP socket connection itself. If kafka-python can connect to a 1.0.0 broker it would still be identified as (0, 10, 1). The only thing you achieve by setting an api_version explicitly is you never actually try to open the TCP socket. But that probably just means that your connection issue will surface later when you try to send or receive messages.

The deeper issue here is a real connection bug that I believe has to do with using all available dns lookup data during bootstrap.

When I explicitly set the api_version, I am able to produce and consume events.

I believe the underlying issue is related to handling multiple network interfaces. My mac, for example, shows three addrinfos for localhost:

('::1', 9092, 0, 0)
('fe80::1%lo0', 9092, 0, 1)
('127.0.0.1', 9092)

The bootstrap and version check code currently only attempt connection on the first addrinfo returned, so if the broker is bound to a later addrinfo then the connection will fail. I fixed this in #1411 .

May I please ask why explicitly setting the api_version always works for me but removing it always fails? It doesn't seem to me that the value of api_version would in any way effect which network interface is bound?

When you set api_version the client will not attempt to probe brokers for version information. So it is the probe operation that is failing. One large difference between the version probe connections and the general connections is that the former only attempts to connect on a single interface per connection (per broker), where as the latter -- general operation -- will cycle through all interfaces continually until a connection succeeds. #1411 fixes this by switching the version probe logic to attempt a connection on all found interfaces.

That makes perfect sense, thank you! 👍

This is fixed on master

@dpkp, I'm using 1.4.2 still encountering this issue. does master branch has been released?

@dpkp same here, using 1.4.2 (installed on March 27, 2018) still getting the error on Macbook

@dpkp Same problem, using 1.4.2, if version not specified, will raise the exception.

I fixed this error with kafka config by adding 'custom kafka broker' with key-value:
advertised.listeners=PLAINTEXT://01.02.03.04:1234

@jeffwji / @nahid / @suesunss can you provide more info?

Will it work fine if you specify the version in kafka-python, and fail if you omit the version?

Is another client working fine (to verify that the broker is indeed running properly)?

@jeffwidman hello, I am using kafka-python 1.4.2.
The problem is: When I am using the new client interface (under client_async.py), API_VERSIONmust be specified, whereas using the old interface (client.py), it works fine.

jar349, specifying version number as you instructed solve 'NoBrokerAvailable' error.

After investigating this issue for a while...
if you're using wurstmeister/kafka with docker-compose, please notice that in Kafka's last version many parameters have been deprecated.
instead of using -

KAFKA_HOST:
KAFKA_PORT: 9092
KAFKA_ADVERTISED_HOST_NAME: <IP-ADDRESS>
KAFKA_ADVERTISED_PORT: 9092

you need to use -

KAFKA_LISTENERS: PLAINTEXT://:9092
KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://<IP-ADDRESS>:9092

view this link for more details

I am having the same problem using hosted Kafka (IBM Cloud) and 1.4.4 version of kafka-python.

If I don't specify api_version, I can't connect to the consumer, and when I do my consumer does not receive any messages.

I meet this problem in centos7, and I fix this by using flowing code

       producer = KafkaProducer(bootstrap_servers='localhost:9092', request_timeout_ms=1000000, api_version_auto_timeout_ms=1000000)

It seems increasing this value api_version_auto_timeout_ms may fix this problem.

@yukurkov @giladsh1 , one of solutions is what you find. thanks

@mrzhangboss works.

After investigating this issue for a while...
if you're using wurstmeister/kafka with docker-compose, please notice that in Kafka's last version many parameters have been deprecated.
instead of using -

KAFKA_HOST:
KAFKA_PORT: 9092
KAFKA_ADVERTISED_HOST_NAME: <IP-ADDRESS>
KAFKA_ADVERTISED_PORT: 9092

you need to use -

KAFKA_LISTENERS: PLAINTEXT://:9092
KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://<IP-ADDRESS>:9092

view this link for more details

How_ do you configure docker-compose
is my docker-compose.yml:

version: '2'

services:
zookeeper:
container_name: zookeeper
image: 'wurstmeister/zookeeper'
ports:
- '2181:2181'
volumes:
- ./zookeeper-data:/bitnami/zookeeper
- /root/kafka/kafka-topics.sh:/kafka-topics.sh
kafka:
image: 'wurstmeister/kafka'
ports:
- '9092:9092'
environment:
KAFKA_LISTENERS: 'PLAINTEXT://:9092'
KAFKA_ADVERTISED_LISTENERS: 'PLAINTEXT://localhost:9092'
KAFKA_ZOOKEEPER_CONNECT: 'zookeeper:2181'
volumes:
- ./kafka-persistence:/bitnami/kafka
- /root/kafka/kafka-topics.sh:/kafka-topics.sh
depends_on:
- zookeeper
container_name: kafka

I had the same problem with kafka_2.12-2.1.0.
The issue was caused by multiple network interfaces on virtual machine images, as commented by user: dpkp. I recreated the VM image with only network interface and reinstalled the application (OSM Release 4) and everything ran as expected.

osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:44 PM Connecting to Kafka server at kafka:9092
osm_pm.1.f5e5rgn6ydhs@osm-r4 | Traceback (most recent call last):
osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:44 PM Bootstrapping cluster metadata from [('kafka', 9092, <AddressFamily.AF_UNSPEC: 0>)]
osm_pm.1.f5e5rgn6ydhs@osm-r4 | File "/usr/local/bin/osm-policy-agent", line 9, in
osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:44 PM : connecting to 10.0.0.17:9092
osm_pm.1.f5e5rgn6ydhs@osm-r4 | load_entry_point('osm-policy-module==1.0', 'console_scripts', 'osm-policy-agent')()
osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:44 PM Bootstrap succeeded: found 1 brokers and 0 topics.
osm_pm.1.f5e5rgn6ydhs@osm-r4 | File "/usr/local/lib/python3.5/dist-packages/osm_policy_module/cmd/policy_module_agent.py", line 66, in main
osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:44 PM : Closing connection.
osm_pm.1.f5e5rgn6ydhs@osm-r4 | agent.run()
osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:44 PM : connecting to 10.0.0.17:9092
osm_pm.1.f5e5rgn6ydhs@osm-r4 | File "/usr/local/lib/python3.5/dist-packages/osm_policy_module/core/agent.py", line 51, in run
osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:44 PM Broker version identifed as 0.11.0
osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:44 PM Set configuration api_version=(0, 11, 0) to skip auto check_version requests on startup
osm_pm.1.f5e5rgn6ydhs@osm-r4 | group_id="pm-consumer")
osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:44 PM Updating subscribed topics to: ['lcm_pm', 'alarm_response']
osm_pm.1.f5e5rgn6ydhs@osm-r4 | File "/usr/local/lib/python3.5/dist-packages/kafka/consumer/group.py", line 324, in init
osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:45 PM Topic alarm_response is not available during auto-create initialization
osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:45 PM Topic lcm_pm is not available during auto-create initialization
osm_pm.1.f5e5rgn6ydhs@osm-r4 | self._client = KafkaClient(metrics=self._metrics, **self.config)
osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:48 PM Group coordinator for pm-consumer is BrokerMetadata(nodeId=1001, host='kafka', port=9092, rack=None)
osm_pm.1.f5e5rgn6ydhs@osm-r4 | File "/usr/local/lib/python3.5/dist-packages/kafka/client_async.py", line 221, in init
osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:48 PM Discovered coordinator 1001 for group pm-consumer
osm_pm.1.f5e5rgn6ydhs@osm-r4 | self.config['api_version'] = self.check_version(timeout=check_timeout)
osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:48 PM Revoking previously assigned partitions set() for group pm-consumer
osm_pm.1.f5e5rgn6ydhs@osm-r4 | File "/usr/local/lib/python3.5/dist-packages/kafka/client_async.py", line 826, in check_version
osm_pm.1.kfdvv4by3ovs@osm-r4 | 02/13/2019 10:28:48 PM (Re-)joining group pm-consumer
osm_pm.1.f5e5rgn6ydhs@osm-r4 | raise Errors.NoBrokersAvailable()
osm_pm.1.f5e5rgn6ydhs@osm-r4 | kafka.errors.NoBrokersAvailable: NoBrokersAvailable

If you are using kafka-python library initialize your producer by specifying api_version. In my case it was "2"

producer = kafka.KafkaProducer(bootstrap_servers=['localhost:9092'], \
                             value_serializer=lambda x:dumps(x).encode('utf-8'), \
                             api_version=(2))

I'm going to close this, as it seems the underlying issue was fixed, and now it's just a catchall... but reading through the most recent comments, it seems most of those that have been traced to root causes are due to environment problems, not library bugs.

If you are stumbling across this through searching, and can't figure it out, please open a new ticket instead of commenting on this one.