All of these options that we discussed earlier are fine when working on a single host, but what they lack is real data portability between different physical hosts. For example, the current methods of keeping data persistent can realistically scale up to but not beyond (without some extreme hacking) a single physical server with single Docker Engine and shared attached storage. This might be fine for a powerful server but starts to lack any sort of use in a true clustering configuration since you might be dealing with an unknown number of servers, mixed virtual and physical hosts, different geographic areas, and so on.
Also when a container is restarted, you most likely will not be able to easily predict where it is going ...
