Linux Systemd Autossh – Autossh Fails on Startup

As explained by @StephenHarris the problem is at the moment systemd tries to read the unit, the file that's symlinked isn't available yet

To just have systemd reload the units after it has mounted :

[Unit]
Description=reloads units stored in /mnt/data
DefaultDependencies=no
After=mnt-data.mount
Requires=mnt-data.mount

[Service]
Type=oneshot
ExecStart=/bin/systemctl daemon-reload

[Install]
WantedBy=local-fs.target

This will cause the units to become available, because this time this time the target of the symlinks is mounted.

But by that time, the list of jobs needing to be run to reach the default.target is already built, and the service won't be started.

To have it also restart your service:

[Unit]
Description=restart unit stored in /mnt/data
Requires=mnt-data.mount

[Service]
Type=oneshot
ExecStart=/bin/systemctl daemon-reload
ExecStartPost=/bin/systemctl start sprinterd.service

[Install]
WantedBy=multi-user.target

Alternatives:

• I've tested with ExecStart= & ExecStartPost=, but it should obviously work with ExecStartPre= & ExecStart=
• if it's all about 1 single unit, you might as well : ExecStart=/bin/systemctl enable /mnt/data/sprinterd.service instead of daemon-reload
• if there are multiple services, do the daemon-reload, then start a single unit that uses ConsistsOf= or PartOf= to load all the multiple services.
• If its NFS (or other networked system), of course local-fs.target isn't your best Installation option, obviously.

For a more old-school SysVinit-style approach, put the systemctl commands inside /etc/rc.local and chmod +x that file.

And then go smuggly post on Devuan's mailing list how you needed SysVInit to fix b0rked SystemD ;-)

Add Restart=always to the service unit, so systemd will keep bringing up the service if it crashes.

On a side note you should use OnUnitInactiveSec instead of OnUnitActiveSec.

OnUnitInactiveSec=10s (or 20s) will start the service 10 seconds after it stopped. This way you make sure it doesn't get called twice and possibly avoid banning for DOSing google