In case we run Spark on Yarn in client mode, we have firewall for Hadoop cluster,
and the client node is outside firewall, I think I have to open some ports
that Application Master uses.
I think the ports is specified by "spark.yarn.am.port" as document says.
But, according to the source code, spark.yarn.am.port is deprecated since 2.0.
Does this mean we do not need to open particular ports of firewall for
Spark on Yarn?