qubes-mirage-firewall VS unikernels

2) https://github.com/mirage/qubes-mirage-firewall is by far a better firewall for Qubes than OpenBSD ever will be - unikernels are far more secure than a traditional operating system is and you can read all about it on https://mirageos.org/

That's correct. It does mean that the closest to a self-contained program you can run is a unikernel like the mirage-firewall, unfortunately. On the upside, those remain easily portable to essentially anything that can run VMs so long as you adjust the image format.

That sounds similar to a unikernel. There are actual uses for those in seL4 and Qubes OS such as a firewall-qube (in theory unikernel qubes should be able to take far less system resources to run than full Linux+distro qubes).

Here's one that is "production" ready: the Mirage-Firewall microkernel running on Qubes OS.[0]

[0] : https://github.com/mirage/qubes-mirage-firewall

sys-net, sys-firewall and other administrative vms should slowly migrate to unikernels instead of running linux, which should help with ram usage. The mirage.io project seems to build a couple qubes vms, for example https://github.com/mirage/qubes-mirage-firewall is a firewall which they indicate to give 64Mb of ram.

Just substitute 'microservice' with 'unikernel' and you do broadly the same things. There's a prometheus library that you link with the MirageOS unikernel and it exports using that: https://github.com/mirage/prometheus

No FAQ for this sort of thing yet, but we should start assembling one sometime soon. Questions like this very welcome on the discussion forums: https://discuss.ocaml.org/t/ann-mirageos-4-0/9598 to help us get started.

There's a nice collection of unikernels over at: https://github.com/roburio/unikernels and https://github.com/tarides/unikernels for various infrastructure pieces (like https, smtp, dns, ip filters, etc) that are good to crib from for your own infrastructure.