In WF 8 + AS 8, we don't start the @DataSourceDefinition until our INSTALL DUP phase.  At some point, we might push JPA DataSource use into the second JPA bootstrap phase or start the DataSourceDefinition service earlier.  For now, applications will more likely avoid DataSourceDefinition but they could set the persistence unit hint "wildfly.jpa.twophasebootstrap" to false as well.