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tutorial-batch-hadoop Tutorial: Load batch data using Apache Hadoop Load from Apache Hadoop

This tutorial shows you how to load data files into Apache Druid using a remote Hadoop cluster.

For this tutorial, we'll assume that you've already completed the previous batch ingestion tutorial using Druid's native batch ingestion system and are using the micro-quickstart single-machine configuration as described in the quickstart.

Install Docker

This tutorial requires Docker to be installed on the tutorial machine.

Once the Docker install is complete, please proceed to the next steps in the tutorial.

Build the Hadoop docker image

For this tutorial, we've provided a Dockerfile for a Hadoop 2.8.5 cluster, which we'll use to run the batch indexing task.

This Dockerfile and related files are located at quickstart/tutorial/hadoop/docker.

From the apache-druid-apache-druid-0.21.1 package root, run the following commands to build a Docker image named "druid-hadoop-demo" with version tag "2.8.5":

cd quickstart/tutorial/hadoop/docker
docker build -t druid-hadoop-demo:2.8.5 .

This will start building the Hadoop image. Once the image build is done, you should see the message Successfully tagged druid-hadoop-demo:2.8.5 printed to the console.

Setup the Hadoop docker cluster

Create temporary shared directory

We'll need a shared folder between the host and the Hadoop container for transferring some files.

Let's create some folders under /tmp, we will use these later when starting the Hadoop container:

mkdir -p /tmp/shared
mkdir -p /tmp/shared/hadoop_xml

Configure /etc/hosts

On the host machine, add the following entry to /etc/hosts:

127.0.0.1 druid-hadoop-demo

Start the Hadoop container

Once the /tmp/shared folder has been created and the etc/hosts entry has been added, run the following command to start the Hadoop container.

docker run -it  -h druid-hadoop-demo --name druid-hadoop-demo -p 2049:2049 -p 2122:2122 -p 8020:8020 -p 8021:8021 -p 8030:8030 -p 8031:8031 -p 8032:8032 -p 8033:8033 -p 8040:8040 -p 8042:8042 -p 8088:8088 -p 8443:8443 -p 9000:9000 -p 10020:10020 -p 19888:19888 -p 34455:34455 -p 49707:49707 -p 50010:50010 -p 50020:50020 -p 50030:50030 -p 50060:50060 -p 50070:50070 -p 50075:50075 -p 50090:50090 -p 51111:51111 -v /tmp/shared:/shared druid-hadoop-demo:2.8.5 /etc/bootstrap.sh -bash

Once the container is started, your terminal will attach to a bash shell running inside the container:

Starting sshd:                                             [  OK  ]
18/07/26 17:27:15 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Starting namenodes on [druid-hadoop-demo]
druid-hadoop-demo: starting namenode, logging to /usr/local/hadoop/logs/hadoop-root-namenode-druid-hadoop-demo.out
localhost: starting datanode, logging to /usr/local/hadoop/logs/hadoop-root-datanode-druid-hadoop-demo.out
Starting secondary namenodes [0.0.0.0]
0.0.0.0: starting secondarynamenode, logging to /usr/local/hadoop/logs/hadoop-root-secondarynamenode-druid-hadoop-demo.out
18/07/26 17:27:31 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
starting yarn daemons
starting resourcemanager, logging to /usr/local/hadoop/logs/yarn--resourcemanager-druid-hadoop-demo.out
localhost: starting nodemanager, logging to /usr/local/hadoop/logs/yarn-root-nodemanager-druid-hadoop-demo.out
starting historyserver, logging to /usr/local/hadoop/logs/mapred--historyserver-druid-hadoop-demo.out
bash-4.1#

The Unable to load native-hadoop library for your platform... using builtin-java classes where applicable warning messages can be safely ignored.

Accessing the Hadoop container shell

To open another shell to the Hadoop container, run the following command:

docker exec -it druid-hadoop-demo bash

Copy input data to the Hadoop container

From the apache-druid-apache-druid-0.21.1 package root on the host, copy the quickstart/tutorial/wikiticker-2015-09-12-sampled.json.gz sample data to the shared folder:

cp quickstart/tutorial/wikiticker-2015-09-12-sampled.json.gz /tmp/shared/wikiticker-2015-09-12-sampled.json.gz

Setup HDFS directories

In the Hadoop container's shell, run the following commands to setup the HDFS directories needed by this tutorial and copy the input data to HDFS.

cd /usr/local/hadoop/bin
./hdfs dfs -mkdir /druid
./hdfs dfs -mkdir /druid/segments
./hdfs dfs -mkdir /quickstart
./hdfs dfs -chmod 777 /druid
./hdfs dfs -chmod 777 /druid/segments
./hdfs dfs -chmod 777 /quickstart
./hdfs dfs -chmod -R 777 /tmp
./hdfs dfs -chmod -R 777 /user
./hdfs dfs -put /shared/wikiticker-2015-09-12-sampled.json.gz /quickstart/wikiticker-2015-09-12-sampled.json.gz

If you encounter namenode errors when running this command, the Hadoop container may not be finished initializing. When this occurs, wait a couple of minutes and retry the commands.

Configure Druid to use Hadoop

Some additional steps are needed to configure the Druid cluster for Hadoop batch indexing.

Copy Hadoop configuration to Druid classpath

From the Hadoop container's shell, run the following command to copy the Hadoop .xml configuration files to the shared folder:

cp /usr/local/hadoop/etc/hadoop/*.xml /shared/hadoop_xml

From the host machine, run the following, where {PATH_TO_DRUID} is replaced by the path to the Druid package.

mkdir -p {PATH_TO_DRUID}/conf/druid/single-server/micro-quickstart/_common/hadoop-xml
cp /tmp/shared/hadoop_xml/*.xml {PATH_TO_DRUID}/conf/druid/single-server/micro-quickstart/_common/hadoop-xml/

Update Druid segment and log storage

In your favorite text editor, open conf/druid/single-server/micro-quickstart/_common/common.runtime.properties, and make the following edits:

Disable local deep storage and enable HDFS deep storage

#
# Deep storage
#

# For local disk (only viable in a cluster if this is a network mount):
#druid.storage.type=local
#druid.storage.storageDirectory=var/druid/segments

# For HDFS:
druid.storage.type=hdfs
druid.storage.storageDirectory=/druid/segments

Disable local log storage and enable HDFS log storage

#
# Indexing service logs
#

# For local disk (only viable in a cluster if this is a network mount):
#druid.indexer.logs.type=file
#druid.indexer.logs.directory=var/druid/indexing-logs

# For HDFS:
druid.indexer.logs.type=hdfs
druid.indexer.logs.directory=/druid/indexing-logs

Restart Druid cluster

Once the Hadoop .xml files have been copied to the Druid cluster and the segment/log storage configuration has been updated to use HDFS, the Druid cluster needs to be restarted for the new configurations to take effect.

If the cluster is still running, CTRL-C to terminate the bin/start-micro-quickstart script, and re-run it to bring the Druid services back up.

Load batch data

We've included a sample of Wikipedia edits from September 12, 2015 to get you started.

To load this data into Druid, you can submit an ingestion task pointing to the file. We've included a task that loads the wikiticker-2015-09-12-sampled.json.gz file included in the archive.

Let's submit the wikipedia-index-hadoop-.json task:

bin/post-index-task --file quickstart/tutorial/wikipedia-index-hadoop.json --url http://localhost:8081

Querying your data

After the data load is complete, please follow the query tutorial to run some example queries on the newly loaded data.

Cleanup

This tutorial is only meant to be used together with the query tutorial.

If you wish to go through any of the other tutorials, you will need to:

  • Shut down the cluster and reset the cluster state by removing the contents of the var directory under the druid package.
  • Revert the deep storage and task storage config back to local types in conf/druid/single-server/micro-quickstart/_common/common.runtime.properties
  • Restart the cluster

This is necessary because the other ingestion tutorials will write to the same "wikipedia" datasource, and later tutorials expect the cluster to use local deep storage.

Example reverted config:

#
# Deep storage
#

# For local disk (only viable in a cluster if this is a network mount):
druid.storage.type=local
druid.storage.storageDirectory=var/druid/segments

# For HDFS:
#druid.storage.type=hdfs
#druid.storage.storageDirectory=/druid/segments

#
# Indexing service logs
#

# For local disk (only viable in a cluster if this is a network mount):
druid.indexer.logs.type=file
druid.indexer.logs.directory=var/druid/indexing-logs

# For HDFS:
#druid.indexer.logs.type=hdfs
#druid.indexer.logs.directory=/druid/indexing-logs

Further reading

For more information on loading batch data with Hadoop, please see the Hadoop batch ingestion documentation.

使用Apache Hadoop加载批数据

本教程向您展示如何使用远程Hadoop集群将数据文件加载到Apache Druid中。

对于本教程，我们假设您已经使用快速入门中所述的 micro-quickstart 单机配置完成了前边的批处理摄取指南。

安装Docker

本教程要求将Docker安装在教程计算机上。

Docker安装完成后，请继续执行本教程中的后续步骤

构建Hadoop Docker镜像

在本教程中，我们为Hadoop 2.8.5集群提供了一个Dockerfile，我们将使用它运行批处理索引任务。

该Dockerfile和相关文件位于 quickstart/tutorial/hadoop/docker。

从apache-druid-0.17.0软件包根目录中，运行以下命令以构建名为"druid-hadoop-demo"的Docker镜像，其版本标签为"2.8.5"：

cd quickstart/tutorial/hadoop/docker
docker build -t druid-hadoop-demo:2.8.5 .

该命令运行后开始构建Hadoop镜像。镜像构建完成后，可以在控制台中看到 Successfully tagged druid-hadoop-demo:2.8.5 的信息。

安装Hadoop Docker集群

创建临时共享目录

我们需要一个共享目录以便于主机和Hadoop容器之间进行传输文件

我们在 /tmp 下创建一些文件夹，稍后我们在启动Hadoop容器时会使用到它们：

mkdir -p /tmp/shared
mkdir -p /tmp/shared/hadoop_xml

配置 /etc/hosts

在主机的 /etc/hosts 中增加以下入口：

127.0.0.1 druid-hadoop-demo

启动Hadoop容器

在 /tmp/shared 文件夹被创建和 /etc/hosts 入口被添加后，运行以下命令来启动Hadoop容器：

docker run -it  -h druid-hadoop-demo --name druid-hadoop-demo -p 2049:2049 -p 2122:2122 -p 8020:8020 -p 8021:8021 -p 8030:8030 -p 8031:8031 -p 8032:8032 -p 8033:8033 -p 8040:8040 -p 8042:8042 -p 8088:8088 -p 8443:8443 -p 9000:9000 -p 10020:10020 -p 19888:19888 -p 34455:34455 -p 49707:49707 -p 50010:50010 -p 50020:50020 -p 50030:50030 -p 50060:50060 -p 50070:50070 -p 50075:50075 -p 50090:50090 -p 51111:51111 -v /tmp/shared:/shared druid-hadoop-demo:2.8.5 /etc/bootstrap.sh -bash

容器启动后，您的终端将连接到容器内运行的bash shell：

Starting sshd:                                             [  OK  ]
18/07/26 17:27:15 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Starting namenodes on [druid-hadoop-demo]
druid-hadoop-demo: starting namenode, logging to /usr/local/hadoop/logs/hadoop-root-namenode-druid-hadoop-demo.out
localhost: starting datanode, logging to /usr/local/hadoop/logs/hadoop-root-datanode-druid-hadoop-demo.out
Starting secondary namenodes [0.0.0.0]
0.0.0.0: starting secondarynamenode, logging to /usr/local/hadoop/logs/hadoop-root-secondarynamenode-druid-hadoop-demo.out
18/07/26 17:27:31 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
starting yarn daemons
starting resourcemanager, logging to /usr/local/hadoop/logs/yarn--resourcemanager-druid-hadoop-demo.out
localhost: starting nodemanager, logging to /usr/local/hadoop/logs/yarn-root-nodemanager-druid-hadoop-demo.out
starting historyserver, logging to /usr/local/hadoop/logs/mapred--historyserver-druid-hadoop-demo.out
bash-4.1#

Unable to load native-hadoop library for your platform... using builtin-java classes where applicable 这个信息可以安全地忽略掉。

进入Hadoop容器shell

运行下边命令打开Hadoop容器的另一个shell：

docker exec -it druid-hadoop-demo bash

拷贝数据到Hadoop容器

从apache-druid-0.17.0安装包的根目录拷贝 quickstart/tutorial/wikiticker-2015-09-12-sampled.json.gz 样例数据到共享文件夹

cp quickstart/tutorial/wikiticker-2015-09-12-sampled.json.gz /tmp/shared/wikiticker-2015-09-12-sampled.json.gz

设置Hadoop目录

在Hadoop容器shell中，运行以下命令来设置本次教程需要的HDFS目录，同时拷贝输入数据到HDFS上：

cd /usr/local/hadoop/bin
./hdfs dfs -mkdir /druid
./hdfs dfs -mkdir /druid/segments
./hdfs dfs -mkdir /quickstart
./hdfs dfs -chmod 777 /druid
./hdfs dfs -chmod 777 /druid/segments
./hdfs dfs -chmod 777 /quickstart
./hdfs dfs -chmod -R 777 /tmp
./hdfs dfs -chmod -R 777 /user
./hdfs dfs -put /shared/wikiticker-2015-09-12-sampled.json.gz /quickstart/wikiticker-2015-09-12-sampled.json.gz

如果在命令执行中遇到了namenode相关的错误，可能是因为Hadoop容器没有完成初始化，等一会儿后重新执行命令。

配置使用Hadoop的Druid

配置用于Hadoop批加载的Druid集群还需要额外的一些步骤。

拷贝Hadoop配置到Druid classpath

从Hadoop容器shell中，运行以下命令将Hadoop.xml配置文件拷贝到共享文件夹中：

cp /usr/local/hadoop/etc/hadoop/*.xml /shared/hadoop_xml

在宿主机上运行下边命令，其中{PATH_TO_DRUID}替换为Druid软件包的路径：

mkdir -p {PATH_TO_DRUID}/conf/druid/single-server/micro-quickstart/_common/hadoop-xml
cp /tmp/shared/hadoop_xml/*.xml {PATH_TO_DRUID}/conf/druid/single-server/micro-quickstart/_common/hadoop-xml/

更新Druid段与日志的存储

在常用的文本编辑器中，打开 conf/druid/single-server/micro-quickstart/_common/common.runtime.properties 文件做如下修改：

禁用本地深度存储，启用HDFS深度存储

#
# Deep storage
#

# For local disk (only viable in a cluster if this is a network mount):
#druid.storage.type=local
#druid.storage.storageDirectory=var/druid/segments

# For HDFS:
druid.storage.type=hdfs
druid.storage.storageDirectory=/druid/segments

禁用本地日志存储，启动HDFS日志存储

#
# Indexing service logs
#

# For local disk (only viable in a cluster if this is a network mount):
#druid.indexer.logs.type=file
#druid.indexer.logs.directory=var/druid/indexing-logs

# For HDFS:
druid.indexer.logs.type=hdfs
druid.indexer.logs.directory=/druid/indexing-logs

重启Druid集群

Hadoop.xml文件拷贝到Druid集群、段和日志存储配置更新为HDFS后，Druid集群需要重启才可以让配置生效。

如果集群正在运行，CTRL-C 终止 bin/start-micro-quickstart脚本，重新执行它使得Druid服务恢复。

加载批数据

我们提供了2015年9月12日起对Wikipedia编辑的示例数据，以帮助您入门。

要将数据加载到Druid中，可以提交指向该文件的摄取任务。我们已经包含了一个任务，该任务会加载存档中包含 wikiticker-2015-09-12-sampled.json.gz文件。

通过以下命令进行提交 wikipedia-index-hadoop.json 任务：

bin/post-index-task --file quickstart/tutorial/wikipedia-index-hadoop.json --url http://localhost:8081

查询数据

加载数据后，请按照查询教程的操作，对新加载的数据执行一些示例查询.

清理数据

本教程只能与查询教程一起使用。

如果您打算完成其他任何教程，还需要：

  • 关闭集群，通过删除Druid软件包中的 var 目录来重置集群状态
  • 将 conf/druid/single-server/micro-quickstart/_common/common.runtime.properties 恢复深度存储与任务存储配置到本地类型
  • 重启集群

这是必需的，因为其他摄取教程将写入相同的"wikipedia"数据源，并且以后的教程希望集群使用本地深度存储。

恢复配置示例：

#
# Deep storage
#

# For local disk (only viable in a cluster if this is a network mount):
druid.storage.type=local
druid.storage.storageDirectory=var/druid/segments

# For HDFS:
#druid.storage.type=hdfs
#druid.storage.storageDirectory=/druid/segments

#
# Indexing service logs
#

# For local disk (only viable in a cluster if this is a network mount):
druid.indexer.logs.type=file
druid.indexer.logs.directory=var/druid/indexing-logs

# For HDFS:
#druid.indexer.logs.type=hdfs
#druid.indexer.logs.directory=/druid/indexing-logs

进一步阅读

更多关于从Hadoop加载数据的信息，可以查看Druid Hadoop批量摄取文档