[jo909]

You would debug an unikernel just like you can debug the OS kernel. Either it brings its own internal "remote debugging API", or the hypervisor helps you with that and provides interactive tracing/debugging features and dumps with CPU and memory state that you load into a local debugger.

The kernel debugging technology exists for a long time now, and I don't think its far fetched to see public clouds exposing those abilities in a secure manner, and unikernels including their own tools for remote debugging. Any kernel can be debugged, and unikernels are no exception.

[peterwwillis]

Then the question becomes, should all application developers become kernel developers/debuggers? Wouldn't that impose a significant barrier to adoption?

[andrewflnr]

Probably (hopefully) no more than having a standard library forces you to be a "standard library debugger". That is to say, a little bit, but you can easily ignore the parts you don't care about.