Hi,
DSS should be able to access the database as soon as the network port for it is accessible from the DSS host (in your case, the VM). And of course this is a mandatory prerequisite.
You can test this by installing and running the mysql client on the VM, and checking that you can reach the database. Once this test works, installing the JAR in DSS and configuring the same JDBC parameters in DSS should be enough (you may need to restart DSS after installing the JAR though).
So the problem should be narrowed to configuring the different network elements between the VM and your database server to allow this connection. This would at least include the VM hypervisor network configuration, and maybe also the firewalls on the hypervisor host and the database host.
As you hinted in a previous message, configuring your DSS VM to be in bridge networking mode may help as it should simplify the problem. In any case, this issue is outside DSS scope and should be investigated with your network administrator.
With best regards
Patrice Bertin
Dataiku