There are many ways to debug unikernels in production, particularly, we have in-kernel monitoring (e.g. ability to enable fine-grain memory, scheduling, and resource monitors. These work also any included libraries). You can also produce flame-graphs of the entire unikernel image which show the entire kernel stack and the application. There is also remote GDB support (which come with additional scripting tools for automation) for debug-images which are built along-side the production image.