No coredump target has been configured. Host dumps cannot be saved (ESXi 5.5)
Stupid little me - removed a storage device on which the coredump target partition was defined. Therefore: "No coredump target has been configured. Host coredump cannot be saved". No idea what to do with such a dump, but I do not like issues with my ESXi hosts, so I set out to fix it. The specific problem I was facing, is not a missing definition of the diagnostics coredump target, but that my target was pointing at a missing storage device.