13.06.2024 Problem:
A client encountered connection errors while attempting to connect to a Cassandra database cluster using cqlsh. The error messages indicated issues related to protocol version compatibility and SSL certificate verification failures (“This version of the driver does not support protocol version 21”).
Process:
Initial Diagnosis: The support team analyzed the error messages provided by the client and suspected potential issues with the Cassandra server version, driver compatibility, and SSL certificate configuration.
Client Verification: The support team requested the client to verify the versions of Cassandra server and cqlsh, as well as the configuration settings related to SSL encryption.
Certificate Configuration: Upon confirming the versions and settings, the team suggested adding the Cassandra certificate to cqlsh and provided instructions for configuring the cqlshrc file with SSL settings.
Client Verification: The client attempted to implement the suggested solution but encountered continued connection errors despite configuring the cqlshrc file with SSL settings.
Further Investigation: Reviewing error logs revealed issues with SSL handshake and unknown certificate authorities, suggesting potential problems with the SSL certificate.
Certificate Comparison: The team compared the SSL certificate used by the client with certificates used on other hosts where cqlsh connections were successful. They also verified the file formats (pem, crt, pkcs12) and ensured consistency.
Live Session: A live troubleshooting session was arranged to delve deeper into the issue. During the session, various aspects including file permissions, configuration syntax, and protocol version compatibility were thoroughly discussed.
Configuration Cleanup: The team cleaned up the cqlshrc file to remove unnecessary comments and ensure correct syntax and formatting. They also adjusted the Cassandra server’s configuration file (cassandra.yaml) to remove client encryption settings that might conflict with SSL connections.
Solution:
After meticulous troubleshooting and debugging, it was discovered that the primary issue lied in a syntax problem within the cqlshrc file. Specifically, there was an error in the SSL configuration syntax that prevented successful SSL connections. Upon rectifying this configuration error, the client was able to establish connections to the Cassandra cluster using cqlsh with SSL encryption.
Conclusion:
The resolution of the connection error highlights the importance of thorough debugging and investigation in troubleshooting technical issues. While the initial error messages suggested problems with SSL certificates, the root cause was identified to be a configuration syntax issue, emphasizing the need for attention to detail in configuration files. Clear communication and collaboration between the support team and the client facilitated the resolution process, ultimately restoring connectivity to the Cassandra database cluster.