Github user yywwd commented on the issue:
https://github.com/apache/zeppelin/pull/2231
I have solved this problem by editing some configurations in Livy.
SivaKaviyappa's solution: setting "livy.spark.master yarn-cluster" does not
work for me. I do not edit "livy.spark.master" in livy.conf. Instead, I
uncomment "livy.spark.deploy-mode" and set the value to cluster. The edited
configuration is:
# What spark deploy mode Livy sessions should use.
livy.spark.deploy-mode cluster---
