如何在 Ubuntu 系统启动时自动启动 Kafka？

Question

Kafka 是否有官方方式（例如 init.d 脚本）在系统启动时启动 Kafka？

我见过的唯一官方启动Kafka的方法是：

nohup ~/kafka/bin/kafka-server-start.sh ~/kafka/config/server.properties > ~/kafka/kafka.log 2>&1 &

我尝试在crontab -e 中使用@reboot 任务，但它没有启动Kafka。有些人还写了自定义的init.d

也有可用的自定义 init.d 脚本（例如 one、two、three），但是它们都是不同的，我对 init.d 不够熟悉，无法理解要实现哪一个（如果有的话） .

如何在系统启动时启动 Kafka？

Answer 1

下载卡夫卡

cd /opt
sudo wget http://mirror.hosting90.cz/apache/kafka/2.5.0/kafka-2.5.0-src.tgz
sudo tar -zxvf kafka-2.5.0-src.tgz
sudo mv kafka-2.5.0-src kafka
sudo rm kafka-2.5.0-src.tgz
cd kafka
sudo ./gradlew jar -PscalaVersion=2.11.12

安装 Zookeeper

sudo vi /etc/systemd/system/zookeeper.service

编辑 zookeeper.service

[Unit]
Requires=network.target remote-fs.target
After=network.target remote-fs.target

[Service]
Type=simple
User=root
ExecStart=/opt/kafka/bin/zookeeper-server-start.sh opt/kafka/config/zookeeper.properties
ExecStop=/opt/kafka/bin/zookeeper-server-stop.sh
Restart=on-abnormal

[Install]
WantedBy=multi-user.target

启动 Zookeeper

sudo systemctl enable zookeeper.service

sudo systemctl start zookeeper.service

sudo systemctl status zookeeper.service

活动（运行）

安装 Kafka

sudo vi /etc/systemd/system/kafka.service

编辑 kafka.service

[Unit]
Requires=zookeeper.service
After=zookeeper.service

[Service]
Type=simple
User=root
ExecStart=/bin/sh -c '/opt/kafka/bin/kafka-server-start.sh /opt/kafka/config/server.properties > /opt/kafka/kafka.log 2>&1'
ExecStop=/opt/kafka/bin/kafka-server-stop.sh
Restart=on-abnormal

[Install]
WantedBy=multi-user.target

启动 Kafka

sudo systemctl enable kafka.service

sudo systemctl start kafka.service

sudo systemctl status kafka.service

活动（运行）

测试 Kafka 是否有效

创建主题

sudo bin/kafka-topics.sh --describe --bootstrap-server localhost:9092 --topic test-topic

将消息放入主题

sudo bin/kafka-console-producer.sh --broker-list localhost:9092 --topic test-topic  
> test message1
> test messate2
^C

从主题中读取消息

sudo bin/kafka-console-consumer.sh --bootstrap-server localhost:9092 --from-beginning --topic test-topic
test message1
test messate2
^C

Answer 2

一种简单的方法是使用 systemd。您应该注意，在启动时，像 JAVA_HOME 这样的环境变量还没有加载，所以我们应该将它们引入系统。一个好的解决方案是创建一个名为 profile 的文件并将所有必要的变量添加到该文件中：

# /home/kafka/profile
JAVA_HOME=/opt/jdk8
KAFKA_HOME=/opt/kafka

假设您已将 Kafka 安装在路径 /opt/kafka 上，以便 Kafka 在 Ubuntu 启动后自动运行（在 Ubuntu 16.04 和 centOS7 上测试，我猜它适用于任何支持 systemd 的发行版）执行以下操作命令：

sudo nano /etc/systemd/system/kafka.service  # open file to add service informations

现在将以下内容添加到文件中

[Unit]
Description=Kafka Daemon
Wants=syslog.target

# suppose you have a service named zookeeper that it start zookeeper and we want Kafka service run after the zookeeper service
After=zookeeper.service

[Service]    
Type=forking

# the user whom you want run the Kafka start and stop command under
User=kafka    

# the file path that contains envirnment variables
EnvironmentFile=/home/kafka/profile

# the directory that the commands will run there   
WorkingDirectory=/home/kafka/ 

# Kafka server start command
ExecStart=/opt/kafka/bin/kafka-server-start.sh -daemon /opt/kafka/config/server.properties

# Kafka server stop command
ExecStop=/opt/kafka/bin/kafka-server-stop.sh -daemon

TimeoutSec=30
Restart=on-failure

[Install]
WantedBy=multi-user.target

注意：由于kafka一开始需要zookeeper连接，所以我想我们也有zookeeper服务，我设置kafka服务在zookeeper服务启动后运行。

现在保存kafka.service文件后，只需运行以下命令创建Kafka服务的链接，每次重启操作系统时它都会启动：

sudo systemctl enable kafka

现在您可以使用以下命令启动 Kafka 服务：

sudo systemctl start kafka.service

并检查服务的状态：

sudo systemctl status kafka.service

Answer 3

以下是我在 Ubuntu 14.04 上配置 Kafka 以自动启动的方式：

sudo su
cp -R ~/kafka_2.11-0.10.0.1 /opt
ln -s /opt/kafka_2.11-0.10.0.1 /opt/kafka

将以下初始化脚本复制到/etc/init.d/kafka：

DAEMON_PATH=/opt/kafka/
PATH=$PATH:$DAEMON_PATH/bin

# See how we were called.
case "$1" in
  start)
        # Start daemon.
        echo "Starting Zookeeper";
        nohup $DAEMON_PATH/bin/zookeeper-server-start.sh -daemon /$DAEMON_PATH/config/zookeeper.properties 2> /dev/null && \
        echo "Starting Kafka";
        nohup $DAEMON_PATH/bin/kafka-server-start.sh -daemon /$DAEMON_PATH/config/server.properties 2> /dev/null
        ;;
  stop)
        # Stop daemons.
        echo "Shutting down Zookeeper";
        pid=`ps ax | grep -i 'org.apache.zookeeper.server' | grep -v grep | awk '{print $1}'`
        if [ -n "$pid" ]
          then
          kill -9 $pid
        else
          echo "Zookeeper was not Running"
        fi
        echo "Shutting down Kafka";
        pid=`ps ax | grep -i 'kafka.Kafka' | grep -v grep | awk '{print $1}'`
        if [ -n "$pid" ]
          then
          kill -9 $pid
        else
          echo "Kafka was not Running"
        fi
        ;;
  restart)
        $0 stop
        sleep 2
        $0 start
        ;;
  status)
        pid=`ps ax | grep -i 'org.apache.zookeeper.server' | grep -v grep | awk '{print $1}'`
        if [ -n "$pid" ]
          then
          echo "Zookeeper is Running as PID: $pid"
        else
          echo "Zookeeper is not Running"
        fi
        pid=`ps ax | grep -i 'kafka.Kafka' | grep -v grep | awk '{print $1}'`
        if [ -n "$pid" ]
          then
          echo "Kafka is Running as PID: $pid"
        else
          echo "Kafka is not Running"
        fi
        ;;
  *)
        echo "Usage: $0 {start|stop|restart|status}"
        exit 1
esac

exit 0

使用以下命令创建 kafka 服务：

chmod 755 /etc/init.d/kafka
update-rc.d kafka defaults

现在您应该可以像这样启动和停止 kafka 服务了：

sudo service kafka start
sudo service kafka status
sudo service kafka stop

如果您想稍后删除 Kafka 服务，请运行 update-rc.d -f kafka remove。