kafka node, consumer got always old messages

Question

im using the module kafka-node https://github.com/SOHU-Co/kafka-node

and every time when i restart consumer they got all old messages, im using round robin system (load balancing)

have you any idea how can i declare to server that i consumed a message, and he do not send me it again when i restart consumer?

some error in my code or config server ?

any idea ?

producer code

var kafka = require('kafka-node');
var HighLevelProducer = kafka.HighLevelProducer;
var Client = kafka.Client;
var client = new Client('xxx.xxx.xxx.xxx:2181,xxx.xxx.xxx.xxx:2181,xxx.xxx.xxx.xxx:2181,xxx.xxx.xxx.xxx:2181,xxx.xxx.xxx.xxx:2181', 'consumer' + process.pid);
var argv = require('optimist').argv;
var topic = argv.topic || 'test_12345';
var producer = new HighLevelProducer(client);
var time = process.hrtime();

var message, diff,i=0;
producer.on('ready', function () {
    setInterval(function(){
        var date = new Date();
        var dateString = date.getFullYear() + "-" +((date.getMonth()+1)<10 ? '0'+(date.getMonth()+1) : (date.getMonth()+1)) + "-" +(date.getDate()<10 ? '0'+date.getDate() : date.getDate()) + " " +(date.getHours()<10 ? '0'+date.getHours() : date.getHours()) + ":" +(date.getMinutes()<10 ? '0'+date.getMinutes() : date.getMinutes()) + ":" +(date.getSeconds()<10 ? '0'+date.getSeconds() : date.getSeconds());
        message = JSON.stringify({'message' : 'hello - '+dateString});
        console.log(message);
        send(message);
    },1000);
});

function send(message) {
    producer.send([
        {topic: topic, messages: [message] }
    ], function (err, data) {
        console.log(data);
        if (err) console.log(err);
    });
}

worker code :

var kafka = require('kafka-node');
var HighLevelConsumer = kafka.HighLevelConsumer;
var Offset = kafka.Offset;
var Client = kafka.Client;
var argv = require('optimist').argv;
var topic = argv.topic || 'test_12345';
var client = new Client('xxx.xxx.xxx.xxx:2181,xxx.xxx.xxx.xxx:2181,xxx.xxx.xxx.xxx:2181,xxx.xxx.xxx.xxx:2181,xxx.xxx.xxx.xxx:2181','consumer'+process.pid);
var payloads = [ { topic: topic }];
var options = {
    groupId: 'kafka-node-group',
// Auto commit config
    autoCommit: true,
    autoCommitMsgCount: 100,
    autoCommitIntervalMs: 5000,
// Fetch message config
    fetchMaxWaitMs: 100,
    fetchMinBytes: 1,
    fetchMaxBytes: 1024 * 10,
    fromOffset: false,
    fromBeginning: false
};
var consumer = new HighLevelConsumer(client, payloads, options);
var offset = new Offset(client);

consumer.on('message', function (message) {
    console.log(this.id, message);
});
consumer.on('error', function (err) {
    console.log('error', err);
});
consumer.on('offsetOutOfRange', function (topic) {
    console.log("------------- offsetOutOfRange ------------");
    topic.maxNum = 2;
    offset.fetch([topic], function (err, offsets) {
        var min = Math.min.apply(null, offsets[topic.topic][topic.partition]);
        consumer.setOffset(topic.topic, topic.partition, min);
    });
});

zookeeper zoo.cfg (5 servers)

The number of milliseconds of each tick
tickTime=2000
# The number of ticks that the initial
# synchronization phase can take
initLimit=10
# The number of ticks that can pass between
# sending a request and getting an acknowledgement
syncLimit=5
# the directory where the snapshot is stored.
# do not use /tmp for storage, /tmp here is just
# example sakes.
dataDir=/etc/zookeeper/data
# the port at which the clients will connect
clientPort=2181
# the maximum number of client connections.
# increase this if you need to handle more clients
#maxClientCnxns=60
#
# Be sure to read the maintenance section of the
# administrator guide before turning on autopurge.    
#
# http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
#
# The number of snapshots to retain in dataDir
autopurge.snapRetainCount=5
# Purge task interval in hours
# Set to "0" to disable auto purge feature
autopurge.purgeInterval=24
server.1=xxx.xxx.xxx.xxx:2888:3888
server.2=xxx.xxx.xxx.xxx:2888:3888
server.3=xxx.xxx.xxx.xxx:2888:3888
server.4=xxx.xxx.xxx.xxx:2888:3888
server.5=xxx.xxx.xxx.xxx:2888:3888
leaderServes = false

kafka server.properties (5 servers)

# 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.
# see kafka.server.KafkaConfig for additional details and defaults

############################# Server Basics #############################

# The id of the broker. This must be set to a unique integer for each broker.
broker.id=5

############################# Socket Server Settings #############################

# The port the socket server listens on
port=9092

# Hostname the broker will bind to. If not set, the server will bind to all interfaces
#host.name=localhost

# Hostname the broker will advertise to producers and consumers. If not set, it uses the
# value for "host.name" if configured.  Otherwise, it will use the value returned from
# java.net.InetAddress.getCanonicalHostName().
#advertised.host.name=<hostname routable by clients>

# The port to publish to ZooKeeper for clients to use. If this is not set,
# it will publish the same port that the broker binds to.
#advertised.port=<port accessible by clients>

# The number of threads handling network requests
num.network.threads=4

# The number of threads doing disk I/O
num.io.threads=8

# The send buffer (SO_SNDBUF) used by the socket server
socket.send.buffer.bytes=1048576

# The receive buffer (SO_RCVBUF) used by the socket server
socket.receive.buffer.bytes=1048576

# The maximum size of a request that the socket server will accept (protection against OOM)
socket.request.max.bytes=104857600


############################# Log Basics #############################

# A comma seperated list of directories under which to store log files
log.dirs=/etc/kafka/kafka-logs

# The default number of log partitions per topic. More partitions allow greater
# parallelism for consumption, but this will also result in more files across
# the brokers.
num.partitions=10

############################# Log Flush Policy #############################

# Messages are immediately written to the filesystem but by default we only fsync() to sync
# the OS cache lazily. The following configurations control the flush of data to disk.
# There are a few important trade-offs here:
#    1. Durability: Unflushed data may be lost if you are not using replication.
#    2. Latency: Very large flush intervals may lead to latency spikes when the flush does occur as there will be a lot of data to flush.
#    3. Throughput: The flush is generally the most expensive operation, and a small flush interval may lead to exceessive seeks.
# The settings below allow one to configure the flush policy to flush data after a period of time or
# every N messages (or both). This can be done globally and overridden on a per-topic basis.

# The number of messages to accept before forcing a flush of data to disk
#log.flush.interval.messages=10000

# The maximum amount of time a message can sit in a log before we force a flush
#log.flush.interval.ms=1000

############################# Log Retention Policy #############################

# The following configurations control the disposal of log segments. The policy can
# be set to delete segments after a period of time, or after a given size has accumulated.
# A segment will be deleted whenever *either* of these criteria are met. Deletion always happens
# from the end of the log.

# The minimum age of a log file to be eligible for deletion
log.retention.hours=168

# A size-based retention policy for logs. Segments are pruned from the log as long as the remaining
# segments don't drop below log.retention.bytes.
#log.retention.bytes=1073741824

# The maximum size of a log segment file. When this size is reached a new log segment will be created.
log.segment.bytes=536870912

# The interval at which log segments are checked to see if they can be deleted according
# to the retention policies
log.retention.check.interval.ms=60000

# By default the log cleaner is disabled and the log retention policy will default to just delete segments after their retention expires.
# If log.cleaner.enable=true is set the cleaner will be enabled and individual logs can then be marked for log compaction.
log.cleaner.enable=false

############################# Zookeeper #############################

# Zookeeper connection string (see zookeeper docs for details).
# This is a comma separated host:port pairs, each corresponding to a zk
# server. e.g. "127.0.0.1:3000,127.0.0.1:3001,127.0.0.1:3002".
# You can also append an optional chroot string to the urls to specify the
# root directory for all kafka znodes.
zookeeper.connect=xxx.xxx.xxx.xxx:2181,xxx.xxx.xxx.xxx:2181,xxx.xxx.xxx.xxx:2181,xxx.xxx.xxx.xxx:2181,xxx.xxx.xxx.xxx:2181

# Timeout in ms for connecting to zookeeper
zookeeper.connection.timeout.ms=1000000    

# metrics reporter properties
#kafka.metrics.polling.interval.secs=5
#kafka.metrics.reporters=kafka.metrics.KafkaCSVMetricsReporter
#kafka.csv.metrics.dir=/etc/kafka/kafka_metrics
# Disable csv reporting by default.
#kafka.csv.metrics.reporter.enabled=false    

replica.lag.max.messages=10000000

default.replication.factor=5
controlled.shutdown.enable=true

cordially

Answer 1

I'm not sure... But it looks that your problem is because you are changing the consumer group every time you run it again (with the process pid) and every consumer group have to get the messages from the beginning...

Answer 2

I had the same problem. I noted that this happens when you consume a topic with more than one partition.

If you specify the partition number in the topic of the consumer it will only consume from one partition and will not get older messages.

Try changing:

var payloads = [ { topic: topic }];

to

var payloads = [ { topic: topic, partition : 0 }];

Answer 3

You should try tweaking following properties -

This setting is in hours so messages on a topic are available for 24*7 hours by default

#Broker Configs
# The minimum age of a log file to be eligible for deletion
log.retention.hours=168

In Consumer Config set auto.commit.enable to true, this will enable consumer to commit the offset to zookeeper for already fetched messages. Also change auto.offset.reset to 'largest' to not read messages from smallest possible offset.

Try this out and see if you still get the problem, you can monitor the offset update for a given consumer through zookeeper commandline. You should look at /consumers and /brokers; following would give you the offset -

get /consumers/my_test_group/offsets/my_topic/0

Hope this helps

Answer 4

Your code works well for me. I tested it with kafka-node v0.2.20.

Focus on zookeeper:

• check logs (e.g. replications errors),
• try one zookeeeper instance,
• try set option leaderServes = true,
• check path /consumers/kafka-node-group/offsets/test_12345/0 by zkCli.sh.