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

This tutorial requires 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-0.22.1 package root, run the following commands to build a Docker image named “druid-hadoop-demo” with version tag “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.

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:

  1. mkdir -p /tmp/shared
  2. mkdir -p /tmp/shared/hadoop_xml

Configure /etc/hosts

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

  1. 127.0.0.1 druid-hadoop-demo
  1. 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:

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:

  1. docker exec -it druid-hadoop-demo bash

Copy input data to the Hadoop container

From the apache-druid-0.22.1 package root on the host, copy the quickstart/tutorial/wikiticker-2015-09-12-sampled.json.gz sample data to the shared folder:

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

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.

  1. cd /usr/local/hadoop/bin
  2. ./hdfs dfs -mkdir /druid
  3. ./hdfs dfs -mkdir /druid/segments
  4. ./hdfs dfs -chmod 777 /druid
  5. ./hdfs dfs -chmod 777 /druid/segments
  6. ./hdfs dfs -chmod 777 /quickstart
  7. ./hdfs dfs -chmod -R 777 /tmp
  8. ./hdfs dfs -chmod -R 777 /user
  9. ./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:

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

  1. mkdir -p {PATH_TO_DRUID}/conf/druid/single-server/micro-quickstart/_common/hadoop-xml

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

  1. #
  2. # Deep storage
  3. #
  5. # For local disk (only viable in a cluster if this is a network mount):
  6. #druid.storage.type=local
  7. #druid.storage.storageDirectory=var/druid/segments
  9. # For HDFS:
  10. druid.storage.type=hdfs
  11. druid.storage.storageDirectory=/druid/segments

Disable local log storage and enable HDFS log storage

  1. #
  2. # Indexing service logs
  3. #
  5. # For local disk (only viable in a cluster if this is a network mount):
  6. #druid.indexer.logs.type=file
  7. #druid.indexer.logs.directory=var/druid/indexing-logs
  9. druid.indexer.logs.type=hdfs
  10. druid.indexer.logs.directory=/druid/indexing-logs

Restart Druid cluster

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.

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 task:

Querying your data

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

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

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:

  1. #
  2. # Deep storage
  3. #
  5. # For local disk (only viable in a cluster if this is a network mount):
  6. druid.storage.type=local
  7. druid.storage.storageDirectory=var/druid/segments
  9. # For HDFS:
  10. #druid.storage.type=hdfs
  11. #druid.storage.storageDirectory=/druid/segments
  13. #
  14. # Indexing service logs
  15. #
  17. # For local disk (only viable in a cluster if this is a network mount):
  18. druid.indexer.logs.type=file
  19. druid.indexer.logs.directory=var/druid/indexing-logs
  21. # For HDFS:
  22. #druid.indexer.logs.type=hdfs

Further reading

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