When SQL Server 2017 on Linux is using a non-default Transmission Control Protocol (TCP) port, you may notice that SQL Server Agent cannot connect to SQL Server 2017 on Docker.
SQL Server Agent does not read the TCPPORT environment variable when it's running in Docker. Therefore, it's not able to discover the port number of SQL server.
This issue is fixed in the following cumulative update for SQL Server:
Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. Check out the latest cumulative updates for SQL Server:
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Learn about the terminologythat Microsoft uses to describe software updates.