apcupsd generated systemd unit file doesn't work

[nh2]

For me on Ubuntu 16.04, `apcupsd` doesn't start when using `sudo systemctl start apcupsd` or `sudo service apcupsd start`.

It didn't appear in `ps aux | grep apc` and I got:

    % systemctl status apcupsd
    ● apcupsd.service - LSB: Starts apcupsd daemon
       Loaded: loaded (/etc/init.d/apcupsd; bad; vendor preset: enabled)
       Active: active (exited) since Wed 2018-01-10 22:21:00 CET; 34min ago
         Docs: man:systemd-sysv-generator(8)
        Tasks: 0
       Memory: 0B
          CPU: 0

Note the `active (exited)` and no processes shown.

I suspect that in this case the `systemd-sysv-generator` messed up and cannot correctly start this SysV-Init unit. So basically, the systemd service seems broken in this version of Ubuntu.

I fixed it by just installing a proper systemd unit using:

    curl https://gist.githubusercontent.com/nh2/e6089d30ddc6be6191037b5098f1adb9/raw/f08e4174286cbba6ab19f619d896da265cb81552/apcupsd.service | sudo tee /etc/systemd/system/apcupsd.service
    sudo systemctl daemon-reload

After that, I can `sudo service apcupsd start` all fine.

That service file has contents

    [Unit]
    Description=APC UPS Power Control Daemon for Linux

    [Service]
    ExecStartPre=-/usr/bin/rm -f /etc/apcupsd/powerfail
    ExecStart=/usr/sbin/apcupsd -b -f /etc/apcupsd/apcupsd.conf

    [Install]
    WantedBy=multi-user.target

I don't know if upstream debian has the same problem, but the same fix would work there.

[nh2 (nh2)]

See also my answers here:

* https://askubuntu.com/a/994508/65575
* https://forum.fhem.de/index.php/topic,64021.msg746445.html#msg746445