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| layout | page_title | sidebar_current | description |
|---|---|---|---|
| guides | Apache Spark Integration - Submitting Applications | guides-spark-submit | Learn how to submit Spark jobs that run on a Nomad cluster. |
Submitting Applications
The spark-submit
script located in Spark’s bin directory is used to launch applications on a
cluster. Spark applications can be submitted to Nomad in either client mode
or cluster mode.
Client Mode
In client mode (the default deployment mode), the Spark application is either directly started by the user, or run directly by sparksubmit, so the application driver runs on a machine that is not necessarily in the Nomad cluster. The driver’s SparkContext creates a Nomad job to run Spark executors. The executors connect to the driver and run Spark tasks on behalf of the application. When the driver’s SparkContext is stopped, the executors are shut down.
Note that the machine running the driver or spark-submit needs to be reachable
from the Nomad clients so that the executors can connect to it.
In client mode, application resources need to start out present on the
submitting machine, so jars (both the primary jar and those added with the
--jars option) can’t be specified using http: or https: URLs. You can either
use files on the submitting machine (either as raw paths or file: URLs), or use
local: URLs to indicate that the files are independently available on both the
submitting machine and all of the Nomad clients where the executors might run.
In this mode, the spark-submit invocation doesn’t return until the application
has finished running, and killing the spark-submit process kills the application.
For example, to submit an application in client mode:
$ spark-submit --class org.apache.spark.examples.SparkPi \
--master nomad \
--conf spark.nomad.sparkDistribution=http://example.com/spark.tgz \
lib/spark-examples*.jar \
10
Cluster Mode
In cluster mode, the spark-submit process creates a Nomad job to run the Spark
application driver itself. The driver’s SparkContext then adds Spark executors to the
Nomad job. The executors connect to the driver and run Spark tasks on behalf of
the application. When the driver’s SparkContext is stopped, the executors are
shut down.
In cluster mode, application resources need to be hosted somewhere accessible
to the Nomad cluster, so jars (both the primary jar and those added with the
--jars option) can’t be specified using raw paths or file: URLs. You can either
use http: or https: URLs, or use local: URLs to indicate that the files are
independently available on all of the Nomad clients where the driver and executors
might run.
Note that in cluster mode, the Nomad master URL needs to be routable from both the submitting machine and the Nomad client node that runs the driver. If the Nomad cluster is integrated with Consul, you may want to use a DNS name for the Nomad service served by Consul.
For example, to submit an application in cluster mode:
$ spark-submit --class org.apache.spark.examples.SparkPi \
--master nomad \
--deploy-mode cluster \
--conf spark.nomad.sparkDistribution=http://example.com/spark.tgz \
http://example.com/spark-examples.jar \
10
Next Steps
Learn how to customize applications.