Exactly the same problem for me, no docker plugin, no backport...
my conf : hp proliant gen8 with esxi, vmware
i have to add : deb https://dl.bintray.com/openmed…evelopers/erasmus-docker2 jessie main
in omv-extras-org.list for docker plugin.
I am reinstalling OMV now again (fourth time) Running on the same hardware as you gen8 with I3 only same ram.