'Twas brillig, and Lennart Poettering at 21/05/12 17:37 did gyre and gimble: > On Wed, 16.05.12 12:07, Colin Guthrie (gm...@colin.guthr.ie) wrote: > >> I thought that the actual end point of the symlink was not all that >> important... >> >> e.g. if I have: >> >> /usr/lib/systemd/system/getty@.service >> /etc/lib/systemd/system/getty@.service >> /etc/lib/systemd/system/multi-user.target.wants/getty@tty1.service -> >> /usr/lib/systemd/system/getty@.service >> >> I thought that the unit file /etc/lib/systemd/system/getty@.service was >> still the one used. i.e. the symlink is merely indicative of whether the >> service is enabled or not, and the actual physical file that it points >> to is not relevant. > > This is not correct. The destination is important. The algorithm works > like this: we traverse the chain of symlinks and add all their names as > alias names to the unit and load the final unit file as source and use > its name as "main" name of the unit file. > > (OK, it's a bit more complicated, since when there is a non-instaniated > unit name in one of the symlink/filenames we implicitly instantiate it > as necessary)
This logic would suggest that I cannot override any units that are enabled statically via a .wants symlink in /lib/... tree. Is that correct? (or does your comment above only apply to template unit names?) >> i.e. The .wants symlink only really states "I'm enabled as an instance >> of getty@.service" and then the normal inheritance rules of >> getty@.service resolution apply *after* that, i.e. getty@.service in >> /etc/... overrides the one in /lib/... > > When looking for a unit file we first look for the instance, and follow > the symlinks there, and if that was not sucessful we look for the > template doing the same. Hmmm, so what happens if I have: /etc/.../x.target.wants/foo@bar.service -> /lib/.../foo@.service /etc/.../x.target.wants/foo@baz.service -> /etc/.../foo@.service Which foo@.service unit is actually used? Will there be two distinct units loaded in memory and each instantiation uses the right one? Or will they both get the /etc one? Or maybe both get the /lib one? Or maybe it's random? Can you maybe also comment on Michal's reply in this thread too where he comments that he considers this behaviour a bug? It would be nice if you could agree on how things should work :) Col -- Colin Guthrie gmane(at)colin.guthr.ie http://colin.guthr.ie/ Day Job: Tribalogic Limited http://www.tribalogic.net/ Open Source: Mageia Contributor http://www.mageia.org/ PulseAudio Hacker http://www.pulseaudio.org/ Trac Hacker http://trac.edgewall.org/ _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
