docker搭建kafka

分布式爬虫框架的部分功能已经开发的差不多了,现在要开始考虑接入kafka了.

kafka依赖于zookeeper, 所以同时需要安装zookeeper

dockerfile-kafka如下

FROM java:8u111-jdk

MAINTAINER stcoder

RUN apt-get update

RUN apt-get -y install wget tar supervisor

WORKDIR /tmp

RUN wget http://mirrors.tuna.tsinghua.edu.cn/apache/kafka/1.0.0/kafka_2.11-1.0.0.tgz

RUN mkdir /home/kafka

RUN tar zxvf kafka_2.11-1.0.0.tgz -C /home

ADD supervisord.conf /etc/supervisord.conf

EXPOSE 2181 2888 3888 9092

CMD ["/usr/bin/supervisord", "-c", "/etc/supervisord.conf"]

这里要说个东西了-----supervisor,我在这个容器里启动了两个服务,zookeeper与kafka,这就是依靠supervisor实现的,下面是supervisor.conf

[supervisord]
nodaemon=true

[program:zookeeper]
command=/home/kafka_2.11-1.0.0/bin/zookeeper-server-start.sh /home/kafka_2.11-1.0.0/config/zookeeper.properties

[program:kafka]
command=/home/kafka_2.11-1.0.0/bin/kafka-server-start.sh /home/kafka_2.11-1.0.0/config/server.properties

接下来是docker-compose.yml

version: '2'
services:
  kafka:
    restart: always
    build:
      context: .
      dockerfile: Dockerfile-kafka
    volumes:
      # 用于将自定义的配置挂载进入容器
      - ./conf/server.properties:/home/kafka_2.11-1.0.0/config/server.properties:ro
      - ./conf/zookeeper.properties:/home/kafka_2.11-1.0.0/config/zookeeper.properties:ro

这里将同级目录下的conf文件夹里的配置文件挂载到容器的卷,从而实现自定义配置

到这里为止,一个单机版本的kafka容器已经构建完成了,接下来就是进行测试了,我们用flask构建一个web服务,用户请求/test时向topic名为mytopic的topic发送一个负载为hello的消息,test-app.py如下

from flask import Flask, request
from confluent_kafka import Producer

app = Flask(__name__)
kafka_conf = {'bootstrap.servers': 'kafka:9092'}

@app.route('/test')
def test():
    p = Producer(kafka_conf)
    p.produce('mytopic', 'hello')
    p.flush()
    return 'ok'

if __name__ == '__main__':
    app.run('0.0.0.0')

然后构建这个webserver的dockerfile-app如下

FROM ubuntu:16.04

MAINTAINER stcoder

RUN apt-get update

RUN apt-get -y install python3 python3-dev python3-pip \
wget software-properties-common python-software-properties

RUN wget -qO - http://packages.confluent.io/deb/4.0/archive.key | apt-key add -
RUN add-apt-repository "deb [arch=amd64] http://packages.confluent.io/deb/4.0 stable main"
RUN apt-get update && apt-get -y install librdkafka-dev

ADD requirements.txt /tmp/requirements.txt

WORKDIR /tmp

RUN pip3 install --upgrade pip

RUN pip3 install -r requirements.txt

WORKDIR /home

RUN mkdir kafka-docker-test

WORKDIR kafka-docker-test

CMD python3 test-app.py

然后整个测试系统的构建的docker-compose.yml如下

version: '2'
services:
  kafka:
    restart: always
    build:
      context: .
      dockerfile: Dockerfile-kafka
    volumes:
      # 用于将自定义的配置挂载进入容器
      - ./conf/server.properties:/home/kafka_2.11-1.0.0/config/server.properties:ro
      - ./conf/zookeeper.properties:/home/kafka_2.11-1.0.0/config/zookeeper.properties:ro
  app:
    restart: always
    build:
      context: .
      dockerfile: Dockerfile-app
    volumes:
      - ./:/home/kafka-docker-test:ro
    ports:
      - "5000:5000"
    links:
      - kafka

整个测试项目的目录结构如下

.
├── conf
│   ├── server.properties
│   └── zookeeper.properties
├── docker-compose.yml
├── Dockerfile-app
├── Dockerfile-kafka
├── requirements.txt
├── supervisord.conf
└── test-app.py

启动docker-compose.yml up后访问127.0.0.1:5000/test
页面返回ok

使用docker exec -it <kafka容器> /bin/bash

进入kafka根目录,

执行bin/kafka-topics.sh --list --zookeeper 127.0.0.1:2181
mytopic

显示mytopic创建成功了,测试到此为止,kafka容器可用

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