systemctl enable and disable a custom service at bootup - linux

Question

I have an application for which I've written a myapp.service file and created a symlink for it in /etc/systemd/system/.
The myapp.service file is like this:
[Unit]
Description=My Application
After=network.target
[Service]
Type=simple
Restart=always
RestartSec=1
StartLimitInterval=0
User=myuser
ExecStart=/var/opt/myapp/myapp
[Install]
WantedBy=multi-user.target
I can use systemctl start myapp, systemctl stop myapp, systemctl status myapp to start, stop, and view the status of the service, and it works very well. I was hoping I could also use systemctl enable myapp, systemctl disable myapp, and systemctl is-enabled myapp to control whether myapp is automatically launched when the system is booted up. When I ran systemctl is-enabled myapp, it showed linked as the output. So I tried systemctl disable myapp and it deleted the symlink to /etc/systemd/system/myapp.service (the output was: Removed symlink /etc/systemd/system/myapp.service.). After that I couldn't run systemctl enable myapp, it just gave this output: Unit myapp.service could not be found.
What is the correct way to create a service such that it can be enabled and disabled with systemctl? I even tried doing it with sshd and was not able to enable after disabling it.
$ systemctl is-enabled sshd
enabled
$ systemctl disable sshd
Removed /etc/systemd/system/multi-user.target.wants/ssh.service.
Removed /etc/systemd/system/sshd.service.
$ systemctl is-enabled sshd
Failed to get unit file state for sshd.service: No such file or directory
$ systemctl enable sshd
Failed to enable unit: Unit file sshd.service does not exist.
Ultimately I just need to ensure that the application does not start at bootup, but can still be controlled with systemctl start myapp, systemctl stop myapp, systemctl status myapp. Does the linked status from systemctl is-enabled myapp mean it will not start at bootup? I tried checking the man page of systemctl, but couldn't find that state.

Answer 1

I can't reproduce on debian (version 244.3-1)
I created /etc/systemd/system/test.service:
me ~ $ sudo systemctl cat test.service
# /etc/systemd/system/test.service
[Unit]
Description=Test
[Service]
Type=oneshot
ExecStart=/bin/true
[Install]
WantedBy=multi-user.target
me ~ $ sudo systemctl enable test.service
Created symlink /etc/systemd/system/multi-user.target.wants/test.service → /etc/systemd/system/test.service.
me ~ $ sudo systemctl disable test.service
Removed /etc/systemd/system/multi-user.target.wants/test.service
As expected, enable/disable creates/deletes a symbolic link to your service in /etc/systemd/system/multi-user.target.wants/. It does not touch /etc/systemd/system/*.service.
I also see that my console messages are slightly different. Which distro/version are you using?