confluent-compose.yml

#!/usr/bin/env -S docker-compose -p kafka -f

version: "3.5"

networks:
  default:
    driver: bridge
    internal: false
    external: false

services:

  nodes:
    image: pvtmert/confluent
    #entrypoint: sh -c
    command: kafkanet
    restart: "no"
    privileged: false
    stdin_open: false
    tty: false
    build:
      context: ./
      dockerfile: confluent.dockerfile
      args: {}
    networks:
      default:
        aliases:
          - kafkanet
    expose:
      - 2181
      - 9092
    labels:
      - traefik.http.routers.web.rule=Host("nodes.kafka.docker.localhost")
    deploy:
      endpoint_mode: dnsrr
      mode: replicated
      replicas: 3
      placement:
        constraints: []
        preferences: []
    healthcheck:
      test: timeout 10 bash -c 'cat </dev/null >/dev/tcp/0/9092'
      interval: 1m
      timeout: 10s
      retries: 3

  gateway:
    image: traefik
    restart: "no"
    command: --api.insecure=true --providers.docker
    networks:
      - default
    ports:
      -   80:80
      - 8080:8080
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock

confluent.dockerfile

#!/usr/bin/env -S docker build --compress -t pvtmert/confluent -f

FROM centos:7

# https://download.java.net/java/GA/jdk11/9/GPL/openjdk-11.0.2_linux-x64_bin.tar.gz

ENV JAVA_HOME="/usr/java"
RUN mkdir -p "${JAVA_HOME}"; \
	curl -#L "https://download.java.net/openjdk/jdk11/ri/openjdk-11+28_linux-x64_bin.tar.gz" \
	| tar --strip=1 -zxC "${JAVA_HOME}"

ENV CONFLUENT_HOME="/home/confluent"
RUN mkdir -p "${CONFLUENT_HOME}" ; \
	curl -#L "https://packages.confluent.io/archive/5.3/confluent-community-5.3.2-2.12.tar.gz" \
	| tar --strip=1 -zxC "${CONFLUENT_HOME}"

ENV CONFLUENT_DATA="${CONFLUENT_HOME}/data"
ENV PATH "${PATH}:${JAVA_HOME}/bin:${CONFLUENT_HOME}/bin"
RUN yum install -y bind-utils which
COPY confluent.init.sh init.sh
ENTRYPOINT [ "bash",  "init.sh" ]
CMD [ ]

EXPOSE \
	2181 \
	2888 \
	3888 \
	9092 \

confluent.init.sh

#!/usr/bin/env bash

#ID="${2}"
DNS="${1}"
DIG="$(which dig)"
INIT=".init.kafka"
FQDN=$(hostname -f)

: ${DNS:?name is required}
IP=$(hostname -i)
ID=$(dig +short "${DNS}" | sort -Vr | grep -n "${IP}" | cut -d: -f1 | head -1)
FQDN=$(dig +short -x "${IP}")

: ${ID?of broker is necessary}
: ${DNS?host is necessary}
: ${CONFLUENT_HOME?is missing}
: ${CONFLUENT_DATA?is missing}
: ${DIG?is required to discover hosts}

FQDN=${FQDN%%.}

function start {
	"zookeeper-server-start" ${CONFLUENT_HOME}/etc/kafka/zookeeper.properties || exit &
	"kafka-server-start"     ${CONFLUENT_HOME}/etc/kafka/server.properties    || exit &
	dig +short -x "${IP}" | printf "My PTR  is: %s\n" "$(cat)"
	hostname -A           | printf "My FQDN is: %s\n" "$(cat)"
	wait
}

test -e "${INIT}" && {
	start
	exit
}

touch "${INIT}"

mkdir -p "${CONFLUENT_DATA}"
echo "${ID:-0}" | tee "${CONFLUENT_DATA}/myid"

tee "${CONFLUENT_HOME}/etc/kafka/zookeeper.properties" <<EOF
dataDir=${CONFLUENT_DATA}
tickTime=2000
initLimit=50
syncLimit=20
clientPort=2181
autopurge.snapRetainCount=3
autopurge.purgeInterval=24
#server.0=0.0.0.0:2888:3888
EOF

for ip in $("${DIG}" +short "${DNS}" | sort -Vr); do
	echo "server.$((++counter))=${ip}:2888:3888"
done \
| sed "s:${IP}:0.0.0.0:g" \
| tee -a "${CONFLUENT_HOME}/etc/kafka/zookeeper.properties"
unset counter

#echo "--------"
#cat "${CONFLUENT_HOME}/etc/kafka/zookeeper.properties"
#echo "--------"

tee -a "${CONFLUENT_HOME}/etc/kafka/server.properties" <<EOF
advertised.listeners=PLAINTEXT://${IP}:9092
zookeeper.connect=${FQDN}:2181
broker.id=${ID:-0}
EOF

start
exit