[Cloudera][ImpalaJDBCDriver](500593) Communication link failure. Failed to connect to server

[#1]

hi community cloudera, 

we are verifying a strange behavior of an Impala connection controller on nifi, when the processor starts the connection, it displays the error below:

[Cloudera][ImpalaJDBCDriver](500593) Communication link failure. Failed to connect to server. Reason: java.net.SocketException: Connection or outbound has closed

communication between hosts is ok, ports communicating without problem.

when we start and stop the processor the connection occurs without problem, this shows that the error is intermittent.

has anyone experienced this type of problem?

[#2]

@yagoaparecidoti Welcome to the Cloudera Community. 

I understand that this connection failure between Impala JDBC Driver and NiFi is randomly disrupted.

Q. Are the other queries from Impala running fine?
Q. Version of NiFi and CDH/CDP?
Q. Is this specific only to the connection between NIFI and the Impala driver?
Q. May I know the size of the cluster?
Q. What are the values set for the following:
idle_session_timeout
idle_query_timeout 
fe_service_threads and
idle_client_poll_time_s
Q. Do you also have TLS-enabled in the client communication?

[#3]

hi @vaishaakb , 

1. Impala-shell queries work without any problems
2. Nifi version 2.2.6.4 on CDP Public Cloud
3. the problem is in the impala connection controller on the nifi to the impala which is on another datahub
4.
idle_session_timeout = no value
idle_query_timeout = no value
fe_service_threads = 64
idle_client_poll_time_s = this parameter does not exist in Impala
5. the environment is Kerberos and TLS enabled