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How to install and configure a Kafka cluster with ZooKeeper

Install and configure a Kafka cluster with ZooKeeper to play with it.

Update package index.

$ sudo apt update

Install GNU privacy guard.

$ sudo apt -y install gpg

Install Java.

$ sudo apt -y install openjdk-11-jre-headless

Create a dedicated kafka user.

$ sudo adduser --system --home /opt/kafka --shell /bin/bash --uid 809  --group --disabled-login kafka

Create a download directory.

$ sudo -u kafka mkdir /opt/kafka/software

Download software and its ASCII-armored signature.

$ sudo -u kafka wget  --quiet --directory-prefix /opt/kafka/software https://downloads.apache.org/kafka/2.8.0/kafka_2.13-2.8.0.tgz
$ sudo -u kafka wget  --quiet --directory-prefix /opt/kafka/software https://downloads.apache.org/kafka/2.8.0/kafka_2.13-2.8.0.tgz.asc

Download the public key used to sign this archive.

$ gpg --keyserver keyserver.ubuntu.com --recv-key 87101C7E5C6DB1C98ADBF93B016CCFCA0E2FD561

Verify signature.

$ gpg --verify /opt/kafka/software/kafka_2.13-2.8.0.tgz.asc /opt/kafka/software/kafka_2.13-2.8.0.tgz
gpg: Signature made Wed Apr 14 14:37:43 2021 UTC
gpg:                using RSA key 87101C7E5C6DB1C98ADBF93B016CCFCA0E2FD561
gpg:                issuer "vvcephei@apache.org"
gpg: Good signature from "John Roesler (CODE SIGNING KEY) " [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: 8710 1C7E 5C6D B1C9 8ADB  F93B 016C CFCA 0E2F D56

Create an application directory.

$ sudo -u kafka mkdir /opt/kafka/kafka

Extract application.

$ sudo -u kafka tar --directory /opt/kafka/kafka --strip-components 1 --extract --file /opt/kafka/software/kafka_2.13-2.8.0.tgz

Create Kafka data directory.

$ sudo -u kafka mkdir /opt/kafka/kafka/kafka_data

Create ZooKeeper data directory.

$ sudo -u kafka mkdir /opt/kafka/kafka/zookeeper_data

Update ZooKeeper myid file.

$ hostname -s | sed "s/.*\([^0-9]\)//g"  | sudo -u kafka tee /opt/kafka/kafka/zookeeper_data/myid

Create ZooKeeper configuration.

$ sudo -u kafka cat <<EOF | tee /opt/kafka/kafka/config/zookeeper.properties
tickTime=2000
initLimit=10
syncLimit=5
dataDir=/opt/kafka/kafka/zookeeper_data
clientPort=2181
server.1=kafka1.example.org:2888:3888
server.2=kafka2.example.org:2888:3888
server.3=kafka3.example.org:2888:3888
EOF

Create Kafka configuration.

$ sudo -u kafka cat <<EOF | tee /opt/kafka/kafka/config/server.properties
# Licensed to the Apache Software Foundation (ASF) under one or more                                                                                                                                                                                                     [83/1881]
# 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=$(hostname -s | sed "s/.*\([^0-9]\)//g")                                                                                                                              
                                                                    
############################# Socket Server Settings #############################
                                                                    
# The address the socket server listens on. It will get the value returned from                                                          
# java.net.InetAddress.getCanonicalHostName() if not configured.                                                                         
#   FORMAT:                                                                                                                              
#     listeners = listener_name://host_name:port                                                                                                                                                                                                                                  
#   EXAMPLE:                                                                                                                             
#     listeners = PLAINTEXT://your.host.name:9092                                                                                        
listeners=PLAINTEXT://:9092                                                                                                                                                                                                                                                      
                                                                                                                                         
# Hostname and port the broker will advertise to producers and consumers. If not set,                                           
# it uses the value for "listeners" if configured.  Otherwise, it will use the value
# returned from java.net.InetAddress.getCanonicalHostName().
advertised.listeners=PLAINTEXT://$(hostname -f):9092

# Maps listener names to security protocols, the default is for them to be the same. See the config documentation for more details
#listener.security.protocol.map=PLAINTEXT:PLAINTEXT,SSL:SSL,SASL_PLAINTEXT:SASL_PLAINTEXT,SASL_SSL:SASL_SSL

# The number of threads that the server uses for receiving requests from the network and sending responses to the network
num.network.threads=3

# The number of threads that the server uses for processing requests, which may include disk I/O
num.io.threads=8

# The send buffer (SO_SNDBUF) used by the socket server
socket.send.buffer.bytes=102400

# The receive buffer (SO_RCVBUF) used by the socket server
socket.receive.buffer.bytes=102400

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

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

# A comma separated list of directories under which to store log files
log.dirs=/opt/kafka/kafka/kafka_data

# 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=6

# The number of threads per data directory to be used for log recovery at startup and flushing at shutdown.
# This value is recommended to be increased for installations with data dirs located in RAID array.
num.recovery.threads.per.data.dir=1

############################# Internal Topic Settings  #############################
# The replication factor for the group metadata internal topics "__consumer_offsets" and "__transaction_state"
# For anything other than development testing, a value greater than 1 is recommended to ensure availability such as 3.
offsets.topic.replication.factor=1
transaction.state.log.replication.factor=1
transaction.state.log.min.isr=1

############################# 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 excessive 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 due to age
log.retention.hours=168

# A size-based retention policy for logs. Segments are pruned from the log unless the remaining
# segments drop below log.retention.bytes. Functions independently of log.retention.hours.
#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=1073741824

# 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=300000

############################# 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=localhost:2181

# Timeout in ms for connecting to zookeeper
zookeeper.connection.timeout.ms=18000


############################# Group Coordinator Settings #############################

# The following configuration specifies the time, in milliseconds, that the GroupCoordinator will delay the initial consumer rebalance.
# The rebalance will be further delayed by the value of group.initial.rebalance.delay.ms as new members join the group, up to a maximum of max.poll.interval.ms.
# The default value for this is 3 seconds.
# We override this to 0 here as it makes for a better out-of-the-box experience for development and testing.
# However, in production environments the default value of 3 seconds is more suitable as this will help to avoid unnecessary, and potentially expensive, rebalances during application startup.
group.initial.rebalance.delay.ms=0
EOF

Create Zookeeper service.

$ cat <<EOF | sudo tee /etc/systemd/system/zookeeper.service
[Unit]
Description=ZooKeeper Service
After=network-online.target 
Requires=network-online.target

[Service]
Type=simple

Restart=on-failure

User=kafka
Group=kafka

ExecStart=/opt/kafka/kafka/bin/zookeeper-server-start.sh /opt/kafka/kafka/config/zookeeper.properties
ExecStop=/opt/kafka/kafka/bin/zookeeper-server-stop.sh /opt/kafka/kafka/config/zookeeper.properties
WorkingDirectory=/opt/kafka

[Install]
WantedBy=multi-user.target
EOF

Create Kafka service.

$ cat <<EOF | sudo tee /etc/systemd/system/kafka.service
[Unit]
Description=kafka Service
After=network-online.target 
Requires=network-online.target

[Service]

Type=simple
Restart=on-failure

User=kafka
Group=kafka

ExecStart=/opt/kafka/kafka/bin/kafka-server-start.sh /opt/kafka/kafka/config/server.properties
ExecStop=/opt/kafka/kafka/bin/kafka-server-stop.sh /opt/kafka/kafka/config/server.properties
WorkingDirectory=/opt/kafka

[Install]
WantedBy=multi-user.target
EOF

Reload systemd configuration.

$ sudo systemctl daemon-reload

Start ZooKeeper.

$ sudo systemctl start zookeeper

Start Kafka.

$ sudo systemctl start kafka