Table of Contents API documentation

Command Line Hadoop Indexer

To run:

java -Xmx256m -Duser.timezone=UTC -Dfile.encoding=UTF-8 -classpath lib/*:<hadoop_config_dir> io.druid.cli.Main index hadoop <spec_file>


  • "--coordinate" - provide a version of Hadoop to use. This property will override the default Hadoop coordinates. Once specified, Druid will look for those Hadoop dependencies from the location specified by druid.extensions.hadoopDependenciesDir.
  • "--no-default-hadoop" - don't pull down the default hadoop version

Spec file

The spec file needs to contain a JSON object where the contents are the same as the "spec" field in the Hadoop index task. In addition, the following fields need to be added to the ioConfig:

      "ioConfig" : {
        "metadataUpdateSpec" : {
          "connectURI" : "jdbc:mysql://localhost:3306/druid",
          "password" : "diurd",
          "segmentTable" : "druid_segments",
          "user" : "druid"
        "segmentOutputPath" : "/MyDirectory/data/index/output"

and the following field need to be added to the tuningConfig:

  "tuningConfig" : {
    "workingPath": "/tmp",

Metadata Update Job Spec

This is a specification of the properties that tell the job how to update metadata such that the Druid cluster will see the output segments and load them.

Field Type Description Required
type String "metadata" is the only value available. yes
connectURI String A valid JDBC url to metadata storage. yes
user String Username for db. yes
password String password for db. yes
segmentTable String Table to use in DB. yes

These properties should parrot what you have configured for your Coordinator.

segmentOutputPath Config

Field Type Description Required
segmentOutputPath String the path to dump segments into. yes

workingPath Config

Field Type Description Required
workingPath String the working path to use for intermediate results (results between Hadoop jobs). no (default == '/tmp/druid-indexing')

Please note that the command line Hadoop indexer doesn't have the locking capabilities of the indexing service, so if you choose to use it, you have to take caution to not override segments created by real-time processing (if you that a real-time pipeline set up).