Livy session stuck on starting after successful spark context creation - apache-spark

Question

I've been trying to create a new spark session with Livy 0.7 server that runs on Ubuntu 18.04.
On that same machine I have a running spark cluster with 2 workers and I'm able to create a normal spark-session.
My problem is that after running the following request to Livy server the session stays stuck on starting state:
import json, pprint, requests, textwrap
host = 'http://localhost:8998'
data = {'kind': 'spark'}
headers = {'Content-Type': 'application/json'}
r = requests.post(host + '/sessions', data=json.dumps(data), headers=headers)
r.json()
I can see that the session is starting and created the spark session from the session log:
20/06/03 13:52:31 INFO SparkEntries: Spark context finished initialization in 5197ms
20/06/03 13:52:31 INFO SparkEntries: Created Spark session.
20/06/03 13:52:46 INFO CoarseGrainedSchedulerBackend$DriverEndpoint: Registered executor NettyRpcEndpointRef(spark-client://Executor) (xxx.xx.xx.xxx:1828) with ID 0
20/06/03 13:52:47 INFO BlockManagerMasterEndpoint: Registering block manager xxx.xx.xx.xxx:1830 with 434.4 MB RAM, BlockManagerId(0, xxx.xx.xx.xxx, 1830, None)
and also from the spark master UI:
and after the livy.rsc.server.idle-timeout is reached the session log then outputs:
20/06/03 14:28:04 WARN RSCDriver: Shutting down RSC due to idle timeout (10m).
20/06/03 14:28:04 INFO SparkUI: Stopped Spark web UI at http://172.17.52.209:4040
20/06/03 14:28:04 INFO StandaloneSchedulerBackend: Shutting down all executors
20/06/03 14:28:04 INFO CoarseGrainedSchedulerBackend$DriverEndpoint: Asking each executor to shut down
20/06/03 14:28:04 INFO MapOutputTrackerMasterEndpoint: MapOutputTrackerMasterEndpoint stopped!
20/06/03 14:28:04 INFO MemoryStore: MemoryStore cleared
20/06/03 14:28:04 INFO BlockManager: BlockManager stopped
20/06/03 14:28:04 INFO BlockManagerMaster: BlockManagerMaster stopped
20/06/03 14:28:04 INFO OutputCommitCoordinator$OutputCommitCoordinatorEndpoint: OutputCommitCoordinator stopped!
20/06/03 14:28:04 INFO SparkContext: Successfully stopped SparkContext
20/06/03 14:28:04 INFO SparkContext: SparkContext already stopped.
and after that the dies :(
I already tried increasing the driver timeout with no luck, and didn't find any known issues like that
my guess it has something to do with the spark driver connectivity to the rsc but I have no idea where to configure that
Anyone knows the reason/solution for that?

Answer 1

We faced a similar problem in one of our environments. The only difference between the working and non-working env was spark master setting in livy.conf file.
I removed the config livy.spark.master=yarn from livy.conf and set this value from the code itself.
// pass master as yarn
public static JavaSparkContext getSparkContext(final String master, final String appName) {
LOGGER.info("Creating spark context");
SparkConf conf = new SparkConf().setAppName(appName);
if (Strings.isNullOrEmpty(master)) {
LOGGER.warn("No spark master found setting local!!");
conf.setMaster("local");
} else {
conf.setMaster(master);
}
conf.set("spark.submit.deployMode", "client");
return new JavaSparkContext(conf);
}
This worked for me.
It would help if anyone can point out, how this worked for me.