#46 Add example systemd units

[Jozef Riha]

I believe it would be nice if duply comes with a set of systemd units that could speed up deployment. After configuring the backup profile user would be expect to run
systemctl --user start duply-backup@profile_name
to initiate backup,
systemctl --user enable --now duply-backup@profile_name.timer to schedule regular daily backup and the same goes for cleanup and verify. With a configured MTA (e. g. msmtp) a report of a failed job can be sent via e-mail).

The example units are attached and are supposed to be placed to /usr/lib/systemd/user.

[ede]

hey Jozef,

looks good to me! would you mind writing up a mini howto step-by-step setup (a little more elaborate than the above notes)?

i'd add it to the distro then as folder 'systemd-unit.examples/' with the HOWTO.txt in it.

thanks!.. ede

[Jozef Riha]

Scheduling backups using systemd timers

One way of setting up a regular backup and backup-related jobs on a systemd-based OS is via systemd timers.
For this purpose duply is coming with a set of units that makes this task easy to implement. The units are located
at /usr/lib/systemd/user and /usr/lib/systemd/system and allow user-independent scheduling of multiple duply profiles.

Let's consider a regular backup with an example humbug profile configured.

This command schedules the backup of this profile in predefined intervals:

$ systemctl --user enable --now duply-backup@humbug.timer

To start the count-down timer we need to run the backup via systemd once:

$ systemctl --user start duply-backup@humbug.service
$ systemctl --user status duply-backup@humbug.service

We can now see the next run has been scheduled by systemd:

$ systemctl --user list-timers

NEXT                         LEFT     LAST                         PASSED    UNIT                      ACTIVATES
Fri 2020-01-10 11:15:47 CET  23h left Thu 2020-01-09 11:05:42 CET  10min ago duply-backup@humbug.timer duply-backup@humbug.service

You may schedule verify (duply-verify@) and cleanup (duply-cleanup@) similarly.

Changing the defaults

To override default scheduling interval create a drop-in service file in /etc/systemd/user. To make
all backups run every 30 minutes create /etc/systemd/user/duply-backup@.timer.d/OnUnitActiveSec.conf
with the following contents:

[Timer]
OnUnitActiveSec=30m

Then reload the configuration:

$ systemctl --user daemon-reload

To override this for a humbug profile only write these changes to /etc/systemd/user/duply-backup@humbug.timer.d/OnUnitActiveSec.conf.

E-mail notification

All units are configured with OnFailure directive that sends e-mail if a unit ends with a failure. This assumes a working MTA, e. g.
msmtp. Note that emails are sent to a user having the profile set, so defining an alias may be required. For msmtp this would be:

/etc/msmtprc
 ..
 ..
 aliases /etc/aliases

/etc/aliases
 MYUSER:  MYUSER@MYPROVIDER.com

Invocation as root

If the goal is to run duply as a root user, repeat the steps with leaving out the --user switch. Drop-in units are to be placed into /etc/systemd/system.

[ede]

released as v2.2.1