I'm curious what you mean by debug. If you mean monitor all of our apps send metrics, health checks, and logs over the wire I'm sure that is independent.
What would docker allow you over the unikernel especially given the best practice push for docker images to only run one thing in a container?
IMO with Unikernel Xen aka Hypervisors are the container holders instead of docker.
With a Docker container, I can exec into it and run strace, ltrace, gdb etc.. With a unikernel it all depends on what you have built into the unikernel. That might provide everything I need, or not. The issue is that we will need a lot of toolking to put unikernels on a sufficiently equal footing vs. being able to run decades worth of Linux tools directly in the containers.
The issue I have with that is the tooling you mention while stable and mature is actively being replaced by cloud tools because you really can't just debug a single machine in production when you have a cluster.. not to mention it is production so debug symbols might not even be available.
I understand your point of the maturity w/ tooling but I see it as a serious failure if you have to log into a machine in production and run gdb or IMO any tool. Your app can and should provide healthchecks/monitoring so that you can see if there is a problem (this includes even a thread stack dump).
I'm probably just biased and jaded as I have had some serious technical debt lost to Docker. It just feels like a VM on top of a VM on top of a VM of continuous things to break/learn... I want baremetal :)
> you really can't just debug a single machine in production when you have a cluster
Somehow I ended up debugging, tracing, monitoring and even hotpatching individual machines in the cluster. Yeah the easy problems will show up in the monitoring and logs. The harder ones won't.
That must have been a pain in the butt :) . And for sure your right there are always exceptions.
I guess I haven't ran into those issues probably because I run JVMs but I suppose if you have native code or an interpreter using native code I can see how it would be helpful to just SSH and figure out what the issue is.
Now that I recall I have actually had to SSH a bunch of times because of Rackspace network interfaces randomly failing so I am a big hypocrite :)