Configuring Apache Druid to use Kerberized Apache Hadoop as deep storage
Following are the configurations files required to be copied over to Druid conf folders:
- For HDFS as a deep storage, hdfs-site.xml, core-site.xml
- For ingestion, mapred-site.xml, yarn-site.xml
HDFS Folders and permissions
Choose any folder name for the druid deep storage, for example 'druid'
Create the folder in hdfs under the required parent folder. For example,
hdfs dfs -mkdir /druidOR
hdfs dfs -mkdir /apps/druid
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
hdfs dfs -chmod 777 /apps/druid
Druid creates necessary sub-folders to store data and index under this newly created folder.
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.
# Deep storage # # For HDFS: =hdfs =/druid/segments # OR # druid.storage.storageDirectory=/apps/druid/segments # # Indexing service logs # # For HDFS: =hdfs =/druid/indexing-logs # OR # druid.storage.storageDirectory=/apps/druid/indexing-logs
Note: Comment out Local storage and S3 Storage parameters in the file
Also include hdfs-storage core extension to
# # Extensions # =dist/druid/extensions =dist/druid/hadoop-dependencies =["mysql-metadata-storage", "druid-hdfs-storage", "druid-kerberos"]
Ensure that Druid has necessary jars to support the Hadoop version.
Find the hadoop version using command,
In case there is other software used with hadoop, like
WanDisco, ensure that
- the necessary libraries are available
- add the requisite extensions to
Create a headless keytab which would have access to the druid data and index.
Edit conf/druid/_common/common.runtime.properties and add the following properties:
Restart Druid Services
With the above changes, restart Druid. This would ensure that Druid works with Kerberized Hadoop