[systemd-devel] How to handle staged installs with a Systemd unit?

[Jeffrey Walton]

On Thu, Dec 26, 2019 at 9:35 AM Mantas Mikulėnas <grawity at gmail.com> wrote:
>
> On Thu, Dec 26, 2019 at 2:46 PM Jeffrey Walton <noloader at gmail.com> wrote:
>>
>> Hi Everyone,
>>
>> My program package includes a systemd timer and service. I was able to
>> setup my Makefile for a regular install using the daemons web page
>> (https://www.freedesktop.org/software/systemd/man/daemon.html).
>>
>> My question is, how should I handle a staged install using DESTDIR?
>> Specifically, should we expect the timer and service to be enabled in
>> the staged directory? Should we expect the timer to be started in the
>> directory?
>
> AFAIK, a staged install with $DESTDIR usually means that you're preparing the files to be collected into a package -- usually to be installed on another system and/or at a later time. So it doesn't make practical sense to start anything at this point.
>
> (And honestly I would **never** expect a Makefile to start any services **at all**. Doesn't matter whether it's staged or not: that is simply not what `make install` does.)

Thanks Mantas.

Yeah, I know what you mean.

> It also doesn't make much sense to call `systemctl enable`, as it's mainly a sysadmin tool. Some distros automatically enable & start services after package installation... but in that case the "enabled" status is still under control by the sysadmin -- it is not hardcoded in the package itself.

I think I'm going to add a start: recipe that will enable and start
services after install for those who want it. It will be a recipe for
non-staged installs.

The reasoning is, users want things that "just work". They don't want
excuses. A "sudo make start" is a little unusual, but I think it is a
better option than the services not starting and users wondering why.
I would not want to be the user trying to track down why a
[unfamiliar] package does not run as expected.

For folks who perform the staged install, I can point them to the
start recipe when they eventually install in the ultimate location.

Jeff