Hi,
We running Knime 4.0.1 and trying to connect to our Spark cluster that runs Spark 2.3 and Livy 0.5.
We have created a small workflow that is a HttpFS Connection node connected to a Create Spark Context (Livy) node. The user in the HttpFS Connection node is Livy and the connection is ok when we test it. When we execute the Create Spark Context (Livy) node it fails after a while and we get the error: “ERROR Create Spark Context (Livy) 3:6 Execute failed: Staging area access from inside Spark failed: nas:/user/livy/.knime-spark-staging-b3c20e38-b7f9-4716-9ca1-90a51dcef127/310fd832-f89c-4b40-b5b9-422b4ef2033c”
We inspected what is happening on the Spark cluster side and it shows that the session was correct started and directly ended by Knime. No faults reported.
When we run this code in a Python Script node it creates a session that stays stable and goes to idle after a while until we deletes it (the input table has the url and port to livy):
import json, pprint, requests, textwrap
host = input_table[‘column1’][0]
data = {‘kind’: ‘spark’}
headers = {‘Content-Type’: ‘application/json’,‘X-Requested-By’:‘livy’}
r = requests.post(host + ‘/sessions’, data=json.dumps(data), headers=headers)
print(r.text)
d = json.loads(r.text)
Do you have any suggestions on what can be wrong?
We tried different staging areas like nas:/user/livy/ without any success and we can’t find any problem with access rights for the livy-user in the cluster.