Are you starting the HA server profile?
Radoslav 's answer pointed to the right direction. the server profile was based on HA, but I transfered it from EAP 6.0.0 and missed to replace
<cache-container name="cluster" aliases="ha-partition" default-cache="default">
<cache-container name="singleton" aliases="cluster ha-partition" default-cache="default">
Correcting it resolved the problem.