Similar exception is on Jetty 9. Workaround is to add resource-ref to web.xml and remove java:comp/env/ prefix from persistence.xml:
web.xml:
<resource-ref> <description>Datasource Name</description> <res-ref-name>jdbc/dsname</res-ref-name> <res-type>javax.sql.XADataSource</res-type> <res-auth>Container</res-auth> </resource-ref>
persistence.xml
<jta-data-source>jdbc/dsname</jta-data-source>