Enable parameterised systemd service from different package

Alexander Broekhuis

Hi all,

I've been struggling with this for a while now, and can't seem to find the proper way, so I hope someone has some hints for me.

I have one package in which a parameterised systemd unit file is added. This package does not add the actual service, only the myservice@.service file.

The recipe looks like:
SRC_URI += " \
file://myservice@.service \

inherit systemd

do_install() {
install -D -m0644 ${WORKDIR}/docker-compose@.service ${D}${systemd_system_unitdir}/docker-compose@.service

SYSTEMD_SERVICE:${PN} = "docker-compose@.service"

FILES:${PN} += "${systemd_system_unitdir}/docker-compose@.service"
Since this recipe does not create any actual service, I doubt the systemd and service creation is actually needed here.

In 2 different packages I want to add an actual service using this unit file, those recipes look like:
inherit systemd 

RDEPENDS:${PN} += "myservice"
SYSTEMD_PACKAGES = "myservice"
SYSTEMD_SERVICE:${PN} = "myservice@..."
However, the myservice@... does not exist/is not created.

I am not certain if I use SYSTEMD_PACKAGES correctly here and if the RDEPENDS is the correct way to add myservice to the dependant packages.

Using a bbappend on myservice does work, however then I end up with both services in all images where myservice is added. Which is not what I want, different services end up in different images.

Image A: IMAGE_INSTALL += myservice actualservice1
Image B: IMAGE_INSTALL += myservice actualservice2

I've thought about 2 workarounds:
1) Create the symbolic link myself, which does feel like a hack
2) Create a custom systemd preset file myself, which should trigger enabling of the service during the first boot

However, reading the documentation of SYSTEMD_PACKAGES, I hoped/expected the above recipe would actually work.