kafka-server-stop.sh not working when Kafka started from Python script

Question

After deploying some Apache Kafka instances on remote nodes I observed problem with kafka-server-stop.sh script that is part of Kafka archive.

By default it contains:

#!/bin/sh
# 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.
ps ax | grep -i 'kafka\.Kafka' | grep java | grep -v grep | awk '{print $1}' | xargs kill -SIGTERM

and this script works great if I execute apache kafka as not background process, for example:

/var/lib/kafka/bin/kafka-server-start.sh /var/lib/kafka/config/server.properties

also it works when I execute it as background process:

/var/lib/kafka/bin/kafka-server-start.sh /var/lib/kafka/config/server.properties &

but on my remote nodes I execute it (with the use of Ansible) with this python script:

#!/usr/bin/env python
import argparse
import os
import subprocess

KAFKA_PATH = "/var/lib/kafka/"

def execute_command_pipe_output(command_to_call):
  return subprocess.Popen(command_to_call, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)

def execute_command_no_output(command_to_call):
  with open(os.devnull, "w") as null_file:
    return subprocess.Popen(command_to_call, stdout=null_file, stderr=subprocess.STDOUT)  

def start_kafka(args):
  command_to_call = ["nohup"]
  command_to_call += [KAFKA_PATH + "bin/zookeeper-server-start.sh"]
  command_to_call += [KAFKA_PATH + "config/zookeeper.properties"]

  proc = execute_command_no_output(command_to_call)

  command_to_call = ["nohup"]
  command_to_call += [KAFKA_PATH + "bin/kafka-server-start.sh"]
  command_to_call += [KAFKA_PATH + "config/server.properties"]

  proc = execute_command_no_output(command_to_call)

def stop_kafka(args):
  command_to_call = [KAFKA_PATH + "bin/kafka-server-stop.sh"]

  proc = execute_command_pipe_output(command_to_call)
  for line in iter(proc.stdout.readline, b''):
    print line,

  command_to_call = [KAFKA_PATH + "bin/zookeeper-server-stop.sh"]

  proc = execute_command_pipe_output(command_to_call)
  for line in iter(proc.stdout.readline, b''):
    print line,


if __name__ == "__main__":
  parser = argparse.ArgumentParser(description="Starting Zookeeper and Kafka instances")
  parser.add_argument('action', choices=['start', 'stop'], help="action to take")

  args = parser.parse_args()

  if args.action == 'start':
    start_kafka(args)
  elif args.action == 'stop':
    stop_kafka(args)
  else:
    parser.print_help()

after executing

manage-kafka.py start
manage-kafka.py stop

Zookeeper is shutdown (as it should be) but Kafka is still running.

What is more interesting, when I invoke (by hand)

nohup /var/lib/kafka/bin/kafka-server-stop.sh

or

nohup /var/lib/kafka/bin/kafka-server-stop.sh &

kafka-server-stop.sh properly shutdowns Kafka instance. I suspect this problem may be caused by some Linux/Python thing.

Answer 1

Kafka brokers need to finish the shutdown process before the zookeepers do.

So start the zookeepers, then the kafka brokers will retry the shutdown process.

I had a similar case. The problem was that my config was not waiting for the kafka brokers to shutdown. Hope this helps somebody. It took me a while to figure out...

Answer 2

I faced this issue a lot before figuring out a brute face way to solve the issue. So what has happened is Kafka closed down abruptly but the port is still in use.

Follow the following steps:

1. Find the process id of the process running at that port: lsof -t -i :YOUR_PORT_NUMBER . ##this is for mac
2. Kill that process kill -9 process_id