Summary
This article addresses an issue where a data source is not responding in the UI, and the server.log shows an error indicating that the connection to the host IP_ADDRESS and port PORT_NUMBER has failed due to a timeout.
Reported Issue
The server.log on the master node displays the following error:
[start-source_name] ERROR c.d.e.s.jdbc.JdbcSchemaFetcherImpl - Connection is not valid.
com.microsoft.sqlserver.jdbc.SQLServerException: The TCP/IP connection to the host IP_ADDRESS, port PORT_NUMBER has failed. Error: "connect timed out. Verify the connection properties. Make sure that an instance of SQL Server is running on the host and accepting TCP/IP connections at the port. Make sure that TCP connections to the port are not blocked by a firewall."
Overview
This is a generic error reported by JDBC, indicating that the specified data source is not reachable. If this is the only error and is not accompanied by other similar errors regarding other sources, it suggests that the connectivity to the specified data source should be tested to determine if it is reachable.
Relevant Versions Tools and Integrations
This can happen on all Dremio releases.
Steps to Resolve
1. From the Dremio coordinator, run a third-party utility to test the connectivity to the data source (e.g., sqlcmd for SQL Server, AWS CLI for AWS Glue, etc.).
2. Alternatively, use network connectivity tools like curl, telnet, or nc to test whether they can connect to the IP address and port specified in the error.
3. If the network connectivity is fine, check the data source's access logs for any connections coming from Dremio and see if they were rejected for any reason.
Common Challenges
Troubleshooting the firewall, gateway or load balancer might be needed as well.