Re: Generating new IDs for cloning (was Re: duplicate popularity-contest ID)
On Thu, 8 Aug 2019 22:44:19 +0100, Simon McVittie <smcv@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
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Marc Haber | " Questions are the | Mailadresse im Header
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