Now I see the answer to this.
Spark slaves are start on random ports, and tell the master where they are.
then the master acknowledges them.
(worker logs)
Starting Spark worker :43282
(master logs)
Registering worker on :43282 with 8 cores, 16.5 GB RAM
Thus, the port is random because
Hi spark !
What is the purpose of the randomly assigned SPARK_WORKER_PORT
from the documentation it sais to join a cluster, but its not clear to me
how a random port could be used to communicate with other members of a
spark pool.
This question might be grounded in my ignorance ... if so
