I have just published what I hope is the best OpenSSH certificate deployment guide out there. Particularly useful for anyone using multiple KVMs/LXCs requiring SSH access without too much administrative overhead, using certificates. Please check the guide and if possible please provide feedback.
https://portal.habitats.tech/OpenSSH/OpenSSH+-1-+Introduction
https://portal.habitats.tech/OpenSSH/OpenSSH+-1-+Introduction