SparkContext allocates random ports. How to control the port allocation.

When SparkContext is in process of creation, a bunch of random ports are allocated to run the Spark service. This can be annoying when you have security groups to think of.

A more detailed post on this topic is here.

Here is an example of how random ports are allocated when Spark service is started:

spark ports random

The only sure bet is 4040 (or 404x depending on how many Spark Web UI have been already started).

On Apache Spark website, under Configuration, under Networking, 6 port properties have default value random. These are the properties that have to be tamed.

spark port random printscreen

(The only 6 properties with default value random among all Spark properties)


Open $SPARK_HOME/conf/spark-defaults.conf:

sudo -u spark vi conf/spark-defaults.conf

The following properties should be added:

spark.blockManager.port    38000
spark.broadcast.port       38001
spark.driver.port          38002
spark.executor.port        38003
spark.fileserver.port      38004
spark.replClassServer.port 38005

I have picked port range 38000-38005 for my Spark services.

If I run Spark service now, the ports in use are now as defined in the configuration file:

spark ports tamed

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