Instead of the /dev/.run trick we have currently implemented, we decided
to move the early-boot runtime dir to /run.
An existing /var/run directory is bind-mounted to /run. If /var/run is
already a symlink, no action is taken.
An existing /var/lock directory is bind-mounted to /run/lock.
If /var/lock is already a symlink, no action is taken.
To implement the directory vs. symlink logic, we have a:
ConditionPathIsDirectory=
now, which is used in the mount units.
Skipped mount unit in case of symlink:
$ systemctl status var-run.mount
var-run.mount - Runtime Directory
Loaded: loaded (/lib/systemd/system/var-run.mount)
Active: inactive (dead)
start condition failed at Fri, 25 Mar 2011 04:51:41 +0100; 6min ago
Where: /var/run
What: /run
CGroup: name=systemd:/system/var-run.mount
The systemd rpm needs to make sure to add something like:
%pre
mkdir -p -m0755 /run >/dev/null 2>&1 || :
or it needs to be added to filesystem.rpm.
Udev -git already uses /run if that exists, and is writable at bootup.
Otherwise it falls back to the current /dev/.udev.
Dracut and plymouth need to be adopted to switch from /dev/.run to run
too.
Cheers,
Kay
This is supposed to play the same roles /var/lib/dbus/machine-id,
however fixes a couple of problems:
- It is available during early boot since it is stored in /etc
- Removes the ID from the D-Bus context and moves it into a system
context, thus hopefully lowering hesitation by people to use it.
- It is generated at installation time. If the file is empty at boot
time it will be mounted over with a randomly generated ID, which is
not saved to disk. This is useful to support state-less machines with
no transient or writable /etc configuration.
