Don't over-complicate it. Write a UUID into /tmp/boot on every boot. Example here, I'm sure there are others:
https://github.com/bsd-source/openbsd-uuid-gen/blob/main/uuid.sh Run from rc.local. /tmp is cleared on every boot (before rc.local is run). Regards Lloyd Ricardo F wrote: > Hello, > > I’m looking for a reliable way to identify a system startup, something > guaranteed to be unique on every boot. > > kern.boottime reflects the system time at boot and is accurate > initially, > but the man page notes: “The boottime variable holds the system boot > time. It > is set from time at system boot, and is updated when the system time is > adjusted with settimeofday(2).”, so it’s not fully immutable. > > Is there a better method to obtain a boot reference that is stable and > unique > for each startup? As example, something like FreeBSD kern.boot_id > sysctl. > > Thanks, > Ricardo F.
