Segment Fetchers

When Pinot segment files are created in external systems (hadoop/spark/etc), there are several ways to push those data to Pinot Controller and Server:

1. push segment to shared NFS and let Pinot pull segment files from the location of that NFS.

2. push segment to a Web server and let Pinot pull segment files from the Web server with http/https link.

3. push segment to HDFS and let Pinot pull segment files from HDFS with hdfs location uri.

4. push segment to other system and implement your own segment fetcher to pull data from those systems.

The first two options should be supported out of the box with Pinot package. As long your remote jobs send Pinot controller with the corresponding URI to the files it will pick up the file and allocate it to proper Pinot Servers and brokers. To enable Pinot support for HDFS, you will need to provide Pinot Hadoop configuration and proper Hadoop dependencies.

HDFS segment fetcher configs

In your Pinot controller/server configuration, you will need to provide the following configs:

pinot.controller.segment.fetcher.hdfs.hadoop.conf.path=`<file path to hadoop conf folder>

or

pinot.server.segment.fetcher.hdfs.hadoop.conf.path=`<file path to hadoop conf folder>

This path should point the local folder containing core-site.xml and hdfs-site.xml files from your Hadoop installation

pinot.controller.segment.fetcher.hdfs.hadoop.kerberos.principle=<your kerberos principal>
pinot.controller.segment.fetcher.hdfs.hadoop.kerberos.keytab=<your kerberos keytab>

or

pinot.server.segment.fetcher.hdfs.hadoop.kerberos.principle=<your kerberos principal>
pinot.server.segment.fetcher.hdfs.hadoop.kerberos.keytab=<your kerberos keytab>

These two configs should be the corresponding Kerberos configuration if your Hadoop installation is secured with Kerberos. Please check Hadoop Kerberos guide on how to generate Kerberos security identification.

You will also need to provide proper Hadoop dependencies jars from your Hadoop installation to your Pinot startup scripts.

Push HDFS segment to Pinot Controller

To push HDFS segment files to Pinot controller, you just need to ensure you have proper Hadoop configuration as we mentioned in the previous part. Then your remote segment creation/push job can send the HDFS path of your newly created segment files to the Pinot Controller and let it download the files.

For example, the following curl requests to Controller will notify it to download segment files to the proper table:

curl -X POST -H "UPLOAD_TYPE:URI" -H "DOWNLOAD_URI:hdfs://nameservice1/hadoop/path/to/segment/file.gz" -H "content-type:application/json" -d '' localhost:9000/segments

Implement your own segment fetcher for other systems

You can also implement your own segment fetchers for other file systems and load into Pinot system with an external jar. All you need to do is to implement a class that extends the interface of SegmentFetcher and provides config to Pinot Controller and Server as follows:

pinot.controller.segment.fetcher.`<protocol>`.class =`<class path to your implementation>

or

pinot.server.segment.fetcher.`<protocol>`.class =`<class path to your implementation>

You can also provide other configs to your fetcher under config-root pinot.server.segment.fetcher.<protocol>