Tue, 16 Dec 2014
I maintain a small software project (about 4k LOC) which is a part of the university infrastructure. It is versioned in Git and installed on several computers across the university. Today I wanted to deploy it on a Fedora 20 machine, which of course is running systemd.
Firstly about my position on systemd: I think most of the things they are trying to acchieve are pretty cool, but sometimes the implementation and design choices are a bit questionable. Anyway, I have written two unit files for my software, even with the unitname@.service wildcard syntax. The units are OK, systemctl start unitname-instance.service works as expected. The crash landing came when I wanted to enable these units after reboot:
# systemctl enable unitname-instance.service Failed to issue method call: No such file or directory
What's wrong with it? It can be systemctl start'd anyway, so the unit files should be OK, shouldn't they? After some hair pulling I have discovered that systemd intentionally ingores symlinks in the /usr/lib/systemd/system directory. Moreover, they just set O_NOFOLLOW and print whatever errno they get from the kernel, which is simply misleading. I think my use case - to have my own unit files in my git repository - is valid, and there is no reason for disallowing symlinked unit files.