On Di, 03.05.22 13:55, Jason A. Donenfeld ([email protected]) wrote:
> I'm still not convinced there's value in having a counter or a UUID, but
> if you had to choose, would you prefer a counter or a UUID? It sounds
> like the former, because you see a use for distinguishing between zero
> and non-zero? Or did you finally agree with me that vmgenid isn't
> granular enough for that?
I would prefer a monotonic counter, since it allows answering
questions like the following:
1. Did this image get cloned at all? (i.e. counter != 0; usecase as per the MAC address
discussion)
2. Did the image get cloned since the last time I looked? (i.e. counter
!= my_previously_saved_counter; usecase: detect clones in an "offline"
fashion, i.e. from a component that doesn't continously run, but
only from time to time)
3. How many clones did I miss? (i.e. missed_clones =
my_previously_saved_counter - counter; usecase: catch up with
generating proxy D-Bus signal messages for clones).
There might be more.
Using a UUID would not give us #1 or #3. It would deliver #2 however.
Lennart
--
Lennart Poettering, Berlin