systemd: Start process as specific user

Two ways:

One, under [Service] include a line „User=<username to run as>“.

Two, use a systemd –user session.

 

 

[Unit] Description=BitTorrent Sync service After=network.target  [Service] ExecStart=/usr/bin/btsync --nodaemon --config /home/%i/.sync/btsync.conf Restart=on-abort User=%i Group=users  [Install] WantedBy=multi-user.target

This allows me to run one instance per user with its own configuration. Since it’s a server with no users actively working on, I think this is the way to go. But will investigate the systemd user session for my desktop clients. smile

 

https://bbs.archlinux.org/viewtopic.php?id=162297

How do I make my systemd service run via specific user and start on boot?
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I just upgraded from Ubuntu server 14 to version 15. I had trouble getting my upstart script working after the upgrade, and read that systemd is the new default. I’m far from a linux expert, so please go easy on me 🙂

Here is what my upstart script was before:

description „NZBGet upstart script“

setuid robert
setgid robert

start on runlevel [2345]
stop on runlevel [016]

respawn

expect fork

script
    exec nzbget -D
end script

pre-stop script
    exec nzbget -Q
end script

Based on the upstart to systemd wiki page, I used the tables provided there to map things as closely as I could in my new systemd service file:

[Unit]
Description=NZBGet Service

[Service]
Type=forking
ExecStart=/usr/local/bin/nzbget -D
ExecStop=/usr/local/bin/nzbget -Q
Restart=on-failure

This file is located at /home/robert/.config/systemd/user/nzbget.service. To start the service manually, I’ve been doing:

$ systemctl –user start nzbget

This works great. However, when I log out of my SSH session, the service shuts down. Also, it does not start on bootup or user login. I want it to behave the same as it did as an upstart service: I want it to start at boot, run constantly, and as a specific user.

What do I need to do to get this configuration?
systemd
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edited May 25 ’16 at 13:44
Braiam
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asked Sep 19 ’15 at 16:17
void.pointer
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2 Answers
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First problem

You can specify the directives User= and Group= in the [Service] section of the unit file.
Second problem

To make the service run on boot, you should not put it in your home folder. Instead, put it under /etc/systemd/system/. This is the folder meant to be used by the system administrator (i.e. you) to add new system-wide services.

Other folders include:

    /usr/lib/systemd/system/ is meant for packages which want to install unit files, though under Debian and Ubuntu the folder is actually /lib/systemd/system/ because the various bin and lib folders have not been merged into a unified /usr/ prefix yet.
    /usr/local/systemd/system/ is for installing units by locally compiled packages.

Testing the unit

Once the unit file is in an appropriate location, you can try starting the unit immediately by typing systemctl start <UNIT_FILENAME> as usual. It should work without having to type the unit’s full path. The extension also doesn’t have to be specified if it’s .service.
Enabling the unit

Before you can enable your unit, you need to add an [Install] section, under which you should add the directive WantedBy=multi-user.target. This directive specifies the stage of the boot-up process during which the service should be started (if it were enabled). multi-user.target is appropriate for most services.

Once that information is added, you can use systemctl enable <UNIT_FILENAME>, which enables the unit, making systemd from now on automatically start it during boot up at the specified stage.
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edited Mar 10 ’16 at 18:13
    
answered Sep 19 ’15 at 16:51
Yamaho
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This worked. I had to specify the absolute path to the service filename in the systemctl enable command though, this was not obvious to me at first. Also enabling gave me some warning about a missing [Install] section. I ignored it, but I’m not sure if it will impact its ability to start at boot time. – void.pointer Sep 19 ’15 at 17:28
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The Install warning was actually really important. It won’t start on boot without WantedBy=multi-user.target under the [Install] section. After adding this to the .service file, then you can enable it. – void.pointer Oct 11 ’15 at 2:37
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I apologize about leaving the answer unattended for such a long time. I fixed the location where the unit file should go, added the missing information about the [Install] section. Hope it’s now more helpful for anyone looking for it. – Yamaho Feb 18 ’16 at 19:50
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This becomes much easier when the username is templated, i.e. your service is defined with a filename in the format something@.service then enabled like something@username.service the setting becomes User=%i meaning the user is not hard-coded and multiple users can use the same definition. An example. – Walf May 6 ’17 at 12:38
       
    
Will it start if I put it under /etc/systemd/user/ ? – Khurshid Alam Sep 4 ’17 at 13:50
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You might be interested in using systemd’s „user lingering“ functionality. It is enabled via loginctl enable-linger USERNAME.

It causes a separate service manager for the respective user being started at boot, so your user-defined units in ~/.config/systemd/user will be picked up and processed at boot and shutdown times according to your service configuration.

You can also use systemctl –user for managing and configuring the service(s), which will operate on your user’s service manager, not the one of the system.
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edited May 14 ’17 at 4:35
Anwar
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answered Dec 11 ’16 at 20:28
byteborg
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systemctl –user is a fantastic finding. Thanks!

 

 

systemd: Start process as specific user