This makes things a bit simpler and the build a bit faster, because we don't
have to rewrite files to do the trivial substitution. @rootbindir@ is always in
our internal $PATH that we use for non-absolute paths, so there should be no
functional change.
`systemd-journal-catalog-update.service` writes to `/var`. However, it's
not explicitly ordered wrt `systemd-tmpfiles-setup.service`, which means
that it may run before or after.
This is an issue for Fedora CoreOS, which uses Ignition. We want to be
able to prepare `/var` on first boot from the initrd, where the SELinux
policy is not loaded yet. This means that the hierarchy under `/var` is
not correctly labeled. We add a `Z /var - - -` tmpfiles entry so that it
gets relabeled once `/var` gets mounted post-switchroot.
So any service that tries to access `/var` before `systemd-tmpfiles`
relabels it is likely to hit `EACCES`.
Fix this by simply ordering `systemd-journal-catalog-update.service`
after `systemd-tmpfiles-setup.service`. This is also clearer since the
tmpfiles entries are the canonical source of how `/var` should be
populated.
For more context on this, see:
https://github.com/coreos/ignition/issues/635#issuecomment-446620297
The service is supposed to regenerate the catalog index whenever /usr is
updated, but /var is not. Hence the ConditionNeedsUpdate= line should
actually reference /var, as that's where the index file is located.
Services which are not crucial to system bootup, and have Type=oneshot
can effectively "hang" the system if they fail to complete for whatever
reason. To allow the boot to continue, kill them after a timeout.
In case of systemd-journal-flush the flush will continue in the background,
and in the other two cases the job will be aborted, but this should not
result in any permanent problem.
The only update service we really need to guard like this is
systemd-tmpfiles-setup.service since if invoked manually might create
/var/run/nologin and thus blocking the user from login. The other
services are pretty much idempotent and don't suffer by this problem,
hence let's simplify them.
Zbigniew Jędrzejewski-Szmek