spark in yarn-cluser 'sc' not defined

Question

I am using spark 1.3.1.

Do I have to declare sc when spark run in yarn-cluster mode? I have no problem running the same python program in spark python shell.

This is how I submit the job :

/bin/spark-submit --master yarn-cluster test.py --conf conf/spark-defaults.conf

where in spark-defaults I did declare where the spark.yarn.jar is, also check permission on where spark.yarn.jar is and /user/admin, the spark user, to make there is read-write-execute for all.

In my test.py program, I have from pyspark.sql import SQLContext and the first line is

sqlctx=SQLContext(sc)

and the error is

NameError: name 'sc' is not defined

on that line.

Any idea?

Answer 1

This is what worked for me:

from pyspark import SparkConf, SparkContext
from pyspark.sql import SQLContext

conf = SparkConf().setAppName("building a warehouse")
sc = SparkContext(conf=conf)
sqlCtx = SQLContext(sc)

Hope this helps.

Answer 2

sc is a helper value created in the spark-shell, but is not automatically created with spark-submit. You must instantiate your own SparkContext and use that

conf = SparkConf().setAppName(appName)
sc = SparkContext(conf=conf)