Hey,
I have some backup services which depend on mounts. I want those
filesystems unmounted when the backup jobs are not running. This is
easily achieved with StopWhenUnneeded.
I also want to trigger the backup jobs to start when I attach my
external HDD. This is reasonably simple by adding WantedBy=<device>
to the backup service (*not* the mount unit, or it will never be
auto-unmounted).
So far so good!
However, this is a headless box and I want to blink an LED when certain
jobs are running, finish or fail. So I need to execute commands in
certain situations. Job failure is easy, I can use OnFailure= and set up
a oneshot service. Job started isn't too bad, I add a ExecStart=-
to my backup service before the real one.
Signalling "device is safe to remove" I have not figured out.
Using a chain of blah.device -> blah.mount -> backup-blah.service units,
"safe to remove" LED should only happen after the mount has completed
unmounting, successfully. Is there an existing "hook" or place that I
could put that in this situation?
My temporary solution is to remove the mount unit entirely, define the
mount point in /etc/fstab and use ExecStart and ExecStop in the backup
service to mount and umount before and after the job runs:
[Unit]
OnFailure=blinkstick-fail.service
[Service]
ExecStart=/bin/mount /media/ipod
# vvv this is a "backup in progress" colour vvv
ExecStart=/usr/local/bin/blinkstick --index 1 --limit 10 --set-color 33c280
ExecStart=/usr/bin/rsync ... # the backup job
ExecStop=/bin/umount /media/ipod
ExecStop=/usr/local/bin/blinkstick --index 1 --limit 10 --set-color green
This works for this simple use-case, but is not very elegant, and I
don't think I can scale this up to my next task: do the same but for an
*encrypted* filesystem. So here I have to have <device> ->
systemd-crpytsetup@<blah>.service -> <blah>.mount (or not?) ->
backup-black.service.
Any advice appreciated. Thanks!
--
Jonathan Dowland
_______________________________________________
systemd-devel mailing list
systemd-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/systemd-devel
