On Thu, 8 Aug 2019 22:44:19 +0100, Simon McVittie <s...@debian.org> wrote: >Making /etc/machine-id a 0-byte file is considered to be the canonical >way to clear it, rather than actually deleting it, because if systemd is >running on a completely read-only root filesystem, it has code to create >a machine ID on a tmpfs and bind-mount it over the top of the empty file.
And what will systemd do when it encounters a zero-sized /etc/machine-id on a writable filesystem? >If you are doing cloning, stateless systems or similar activities, >and you know you will have a valid /etc/machine-id (you either use >systemd or have taken other steps to have one), then you can make >/var/lib/dbus/machine-id a symlink to /etc/machine-id (dbus comes with a >systemd-tmpfiles file to do this). This is not done by default in Debian, >or by `dbus-uuidgen --ensure`, for historical reasons; maybe it should be, >but to be confident that it was a correct change I'd have to think about >the ways in which it might go wrong on non-systemd systems (with either >a non-systemd init like sysvinit, or no init at all like minimal chroots). Interesting, I see this on a number of my test systems without having been active in this regard myself. >Maybe /etc/machine-id should be part of the "API" of a Debian system in >general (systemd or not)? please elaborate on that. Greetings Marc -- -------------------------------------- !! No courtesy copies, please !! ----- Marc Haber | " Questions are the | Mailadresse im Header Mannheim, Germany | Beginning of Wisdom " | Nordisch by Nature | Lt. Worf, TNG "Rightful Heir" | Fon: *49 621 72739834