Consider such a scenario :

Several hibernate instance share the same cache.

As I know , multi ehcache3 support share same cache, but hibernate5.2.4 integration with ehcache3 do not support. the integration only support heap cache, and the integration does not support cache at ehcache xml config.

When hibernate will support this scenario?

Hibernate offers the same set of second-level cache API for any implementation, being it Ehcache, Infinispan or Hazelcast.

If you need a clustered Ehcache solution, then you should use Terracotta server, but that not open-source.

If you're looking for an open-source solution, you should use Infinispan, which is developed by Red Hat, just like Hibernate.