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Configure Apache Druid to use Kerberized Apache Hadoop as deep storage

docs/tutorials/tutorial-kerberos-hadoop.md

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Setup

Following are the configurations files required to be copied over to Druid conf folders:

  1. hdfs-site.xml
  2. core-site.xml

HDFS Folders and permissions

  1. Choose any folder name for the druid deep storage, for example 'druid'

  2. Create the folder in hdfs under the required parent folder. For example, hdfs dfs -mkdir /druid OR hdfs dfs -mkdir /apps/druid

  3. Give druid processes appropriate permissions for the druid processes to access this folder. This would ensure that druid is able to create necessary folders like data and indexing_log in HDFS. For example, if druid processes run as user 'root', then

    hdfs dfs -chown root:root /apps/druid

    OR

    hdfs dfs -chmod 777 /apps/druid

Druid creates necessary sub-folders to store data and index under this newly created folder.

Druid Setup

Edit common.runtime.properties at conf/druid/_common/common.runtime.properties to include the HDFS properties. Folders used for the location are same as the ones used for example above.

common.runtime.properties

properties
# Deep storage
#
# For HDFS:
druid.storage.type=hdfs
druid.storage.storageDirectory=/druid/segments
# OR
# druid.storage.storageDirectory=/apps/druid/segments

Note: Comment out Local storage and S3 Storage parameters in the file

Also include hdfs-storage core extension to conf/druid/_common/common.runtime.properties

properties
#
# Extensions
#

druid.extensions.directory=dist/druid/extensions
druid.extensions.loadList=["mysql-metadata-storage", "druid-hdfs-storage", "druid-kerberos"]

Kerberos setup

Create a headless keytab which would have access to the druid data.

Edit conf/druid/_common/common.runtime.properties and add the following properties:

properties
druid.hadoop.security.kerberos.principal
druid.hadoop.security.kerberos.keytab

For example

properties
[email protected]
druid.hadoop.security.kerberos.keytab=/etc/security/keytabs/hdfs.headless.keytab

Restart Druid Services

With the above changes, restart Druid. This would ensure that Druid works with Kerberized Hadoop