Not able to connect to MySQL database when using Apache NiFi in Linux Ubuntu - mysql

Question

I am trying to connect to a MySQL RDS instance in AWS with Apache NiFi on Linux Ubuntu.
The MySQL database is behind a SSH tunnel which is working in a dedicated terminal. The MySQL database is accessible through another Linux terminal.
$ ssh -i /home/bernardo/.ssh/sshbernardo3.pem -N \
-L 33061:<db_name>.<id>.eu-west-1.rds.amazonaws.com:3306 \
<user>#<ip_address> -p <port>
I have uploaded and unzipped the JDBC driver from https://downloads.mysql.com/archives/c-j/
The file java.sql.Driver is located in the directory /usr/share/java/META-INF/services in Linux
I have installed the jdbc connector in Linux and set up the user to use JDBC
$ sudo apt-get install libmysql-java
$ cd /home/bernardo
$ gedit .bashrc
Added the following lines at the end of the file:
# Setting up the user to use JDBC
CLASSPATH=$CLASSPATH:/usr/share/java/mysql-connector-java-8.0.26.jar
export CLASSPATH
Then source it:
$ source .bashrc
In NiFi I have used a DBCPConnectionPool1.15.2 controller service which is configured as follows:
• Database Connection URL: jbdc:mysql://127.0.0.1:33061/<db_name>
• Database Driver Class Name: java.sql.Driver
• Database Driver Location: /usr/share/java/META-INF/services
• Database User: <db_user>
• Password: <db_password>
When enabling the controller service, I get the following error:
StandardControllerServiceNode[service=DBCPConnectionPool[id=2440f624-017e-1000-9467-8bb12dda6ca6],
name=<controller_service_name>, active=true] Failed to invoke
#OnEnabled method due to java.lang.NoSuchMethodException:
java.sql.Driver.() causes: java.lang.InstantiationException:
java.sql.Driver causes:
org.apache.nifi.processor.exception.ProcessException: Creating driver
instance is failed: Creating driver instance is failed
Any hint?
This is the SW I have installed:
Linux Ubuntu 18.04.6 in VirtualBox 6.1 on top of Windows 10 Pro
openjdk version "11.0.13" 2021-10-19
javac 11.0.13
nifi-1.15.2
Thanks,
Bernardo
EDITED on 2022 January 6 08:50 UTC
I have made the following changes to the DBCPConnectionPool1.15.2 controller service configuration:
• Database Driver Class Name: com.mysql.cj.jdbc.Driver
• Database Driver Location: /usr/share/java/mysql-connector-java-8.0.26.jar
The other parameters are not changed:
• Database Connection URL: jbdc:mysql://127.0.0.1:33061/<db_name>
• Database User: <db_user>
• Password: <db_password>
The file mysql-connector-java-8.0.26.jar is in /usr/share/java
Also:
$ cat /usr/share/java/META-INF/services/java.sql.Driver
com.mysql.cj.jdbc.Driver
And:
$ netstat -nplt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 127.0.0.1:33061 0.0.0.0:* LISTEN 4873/ssh
tcp6 0 0 ::1:33061 :::* LISTEN 4873/ssh
Still I get an error (a new error this time):
causes: org.apache.nifi.processor.exception.ProcessException: No suitable driver for the given Database Connection URL
Permissions to access the driver jar file:
bernardo#BDi-laptop:/usr/share/java$ ls -l
-rwxrwxr-- 1 bernardo bernardo 2462344 gen 4 19:01 mysql-connector-java-8.0.26.jar
EDITED on 2022 January 6 10:21 UTC
Added the CLASSPATH variable also in /etc/environment
bernardo#BDi-laptop:/usr/share/java$ echo $CLASSPATH
.:/usr/share/java/mysql-connector-java-8.0.26.jar:/usr/share/java/mysql-connector-java-8.0.26.jar
EDITED on 2022 January 7 09:08 UTC
I thought it could be an issue related to the driver version so I re-installed the jdbc driver. I have cleaned /home/bernardo/Download and /usr/share/java from the old sql related files. Then I have done the installation again.
Install the jdbc connector
$ sudo apt-get install libmysql-java
The .jar file is in /usr/share/java/mysql-connector-java-5.1.45.jar
Unpack the .jar file
$ sudo jar xvf /usr/share/java/mysql-connector-java-5.1.45.jar
To find the driver class name, open /usr/share/java/META-INF/services/java.sql.Driver
$ cat /usr/share/java/META-INF/services/java.sql.Driver
com.mysql.jdbc.Driver
com.mysql.fabric.jdbc.FabricMySQLDriver
The driver class name is: com.mysql.jdbc.Driver
This is the updated configuration in the DBCPConnectionPool1.15.2 controller service in Apache Ni-Fi:
• Database Driver Class Name: com.mysql.jdbc.Driver
• Database Driver Location: /usr/share/java/mysql-connector-java-5.1.45.jar
• Database Connection URL: jbdc:mysql://127.0.0.1:33061/<db_name>
• Database User: <db_user>
• Password: <db_password>
I have obtained the same result:
causes: org.apache.nifi.processor.exception.ProcessException: No suitable driver for the given Database Connection URL
Then I checked if the problem was in the SSH tunnel.
$ netstat -nplt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 127.0.0.1:33061 0.0.0.0:* LISTEN 4497/ssh
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN -
tcp6 0 0 ::1:33061 :::* LISTEN 4497/ssh
$ cat /proc/4497/status
Name: ssh
State: S (sleeping)
The SSH process is in sleeping state.
In a separate terminal I accessed the remote MySQL database:
$ mysql -u <db_user> -p -h 127.0.0.1 -P 33061
Finally, I tried to connect to my local mysql database in my local Linux instance by using the following Ni-Fi settings:
• Database Driver Class Name: com.mysql.jdbc.Driver
• Database Driver Location: /usr/share/java/mysql-connector-java-5.1.45.jar
• Database Connection URL: jbdc:mysql://127.0.0.1:3306/<local_db_name>
• Database User: <local_db_user>
• Password: <local_db_password>
I have obtained the same result:
causes: org.apache.nifi.processor.exception.ProcessException: No suitable driver for the given Database Connection URL
Still, in a separate Linux terminal I am able to access the local mysql database:
$ mysql -u <local_db_user> -p -h 127.0.0.1 -P 3306
EDITED on 2022 January 10 11:58 UTC
Corrected a typo in Ni-Fi controller service configuration:
• Database Connection URL: jdbc:mysql://127.0.0.1:33061/<db_name>
Controller service problem solved!
Thanks!
EDITED on 2022 January 12 08:26 UTC
I am still getting connectivity problems. I managed to enable the controller service but, when I run the processor QueryDatabaseTable, I get the following error: Cannot create PoolableConnectionFactory - Communications link failure
QueryDatabaseTable[id=017e1003-c2d8-14cf-4e34-feee76411595] Unable to execute SQL select query SELECT * FROM periodic_measurements_test due to java.sql.SQLException: Cannot create PoolableConnectionFactory (Communications link failure
The last packet successfully received from the server was 0 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.): javax.net.ssl.SSLHandshakeException: No appropriate protocol (protocol is disabled or cipher suites are inappropriate)
↳ causes: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 0 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.
↳ causes: java.sql.SQLException: Cannot create PoolableConnectionFactory (Communications link failure
The last packet successfully received from the server was 0 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.)
↳ causes: org.apache.nifi.processor.exception.ProcessException: java.sql.SQLException: Cannot create PoolableConnectionFactory (Communications link failure
The last packet successfully received from the server was 0 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.)
The processor configuration is default except for:
• Database Connection Pooling Service: < DBCPConnectionPool controller service name >
• Database Type: MySQL
• Table Name: periodic_measurements_test
The controller service configuration is still:
• Database Connection URL: jdbc:mysql://127.0.0.1:33061/<db_name>
• Database Driver Class Name: com.mysql.jdbc.Driver
• Database Driver Location: /usr/share/java/mysql-connector-java-5.1.45.jar
• Database User: <db_user>
• Password: <db_password>
The SSH tunnel seems to be fine:
netstat -nplt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 127.0.0.1:33061 0.0.0.0:* LISTEN 29483/ssh
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN -
tcp 0 0 127.0.0.1:8443 0.0.0.0:* LISTEN -
And in Linux terminal I can still access the MySQL database thorough CLI:
$ mysql -u <db_user> -p -h 127.0.0.1 -P 33061
And I get the same result when I try to fetch data from the MySQL database in my local Linux instance.

Answer 1

Finally, I managed to fix the issue. It was related to the version of the jdbc driver.
I did the following:
In Linux browser go to https://dev.mysql.com/downloads/connector/j/
Select
• Ubuntu Linux
• 18.04
Download
In a CLI terminal go to the Downloads directory
$ cd /home/bernardo/Downloads
Unpack the deb file
$ sudo dpkg -i mysql-connector-java_8.0.26-1ubuntu18.04_all.deb
Check where is the connector location in the file system
$ dpkg -L mysql-connector-java | fgrep jar
/usr/share/java/mysql-connector-java-8.0.26.jar
Clean /usr/share/java from the previous jdbc driver
$ sudo rm mysql-connector-java-5.1.45.jar
$ sudo rm -r com
$ sudo rm -r META-INF/
Install the connector: unpack the .jar file
$ sudo jar xvf /usr/share/java/mysql-connector-java-8.0.26.jar
To find the driver class name, open /usr/share/java/META-INF/services/java.sql.Driver
$ cat /usr/share/java/META-INF/services/java.sql.Driver
com.mysql.cj.jdbc.Driver
The driver class name is: com.mysql.jdbc.Driver
Restart Apache Ni-Fi
Modify the configuration of the controller service with:
• Database Driver Class Name: com.mysql.cj.jdbc.Driver
• Database Driver Location: /usr/share/java/mysql-connector-java-8.0.26.jar