JMeter Unable to connect AWS RDS getting error java.sql.SQLException: Cannot create PoolableConnectionFactory (Communications link failure

Question

I have to connect my JMeter script to AWS RDS database. When I am running my test with the below JDBC Connection configuration it is showing this error message:

java.sql.SQLException: Cannot create PoolableConnectionFactory (Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.)

JDBC Connection configuration:

JDBC Request:

Response Error Message:

I already added mysql-connector-java-8.0.25.jar file in Jmeter's /lib folder, but it didn't help.

Answer 1

From JMeter perspective your connection configuration looks OK, the problem is on RDS end. The only thing you can do from JMeter is try increasing JMeter logging verbosity for the MySQL Connector/J in order to get more troubleshooting information in jmeter.log file, the line to be added to JMeter's log4j2.xml file is:

<Logger name="com.mysql.jdbc" level="debug" />

Troubleshooting steps for RDS/AWS/MySQL:

• Make sure to open port 3306 in the RDS Security Groups
• Make sure to whitelist the external IP address of your JMeter machine(s) in the VPC Security Group (or use wildcard like 0.0.0.0/0 so anyone will be able to connect)
• Make sure that your MySQL instance is bound to the public IP address or listening on all interfaces, see bind-address directive