You are always gonna have some downtime in a homelab setup I think. Unless you go all in with k8s I think the best you can do is "system reboots at 4AM, hopefully all the users are asleep".
(Probably a lot of the services I run don't even really support HA properly in a k8s system with replicas. E.g. taking global exclusive DB locks for the lifetime of their process)
(Probably a lot of the services I run don't even really support HA properly in a k8s system with replicas. E.g. taking global exclusive DB locks for the lifetime of their process)