Unable to change the Ports

[ji...@wipro.com]

Hi Everyone i am new to spark ... I am posting some basic doubts
 i met while trying to create a standalone cluster for a small poc ...

1)My Corporate firewall blocked the port 7077, which is the default port of Master URL ,
So i used  start-master.sh --port 8080 (also tried with several other ports and -p)
 but still the port used by master was unchanged.
I resolved this problem by addingexport SPARK_MASTER_PORT="59468" in  spark-env.sh . My first doubt is why -p PORT, --port PORT didn't work?

2)same result when tried with spark spark-class org.apache.spark.deploy.worker.Worker spark://IP:PORT

3)Also Why is by default the port random for worker

..Sorry if i am being stupid

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