CentOS - Sep 2021 - systemd | Requires statement with an instantiated service

Maybe the work day is already to long. I can not find
a solution for following requirement.

How to apply a "Requires" with an instantiated service.

Example:

a at .service
b.service

a at .service is started as a at host1.service and b.service must be started
after a at host1.service but the unit will be differently parameterized
(depended of the region). So I want to generalize the requires statement.

My dropin file in ./b.service.d/dep.conf looks like

[Unit]
Requires="a@*.service"

This just produces following error:
'Failed to add dependency on "a@*.service", ignoring: Invalid
argument'


I use also a Before=b.service statement for a at .service but that is not
enough.

Any hints?

--
Thanks,
Leon

--On Wednesday, September 01, 2021 6:36 PM +0200 Leon Fauster via CentOS 
<centos at centos.org> wrote:
> How to apply a "Requires" with an instantiated service.
>
> Example:
>
> a at .service
> b.service
>
> a at .service is started as a at host1.service and b.service must be
started
> after a at host1.service but the unit will be differently parameterized
> (depended of the region). So I want to generalize the requires statement.
>
> My dropin file in ./b.service.d/dep.conf looks like
>
> [Unit]
> Requires="a@*.service"
>
> This just produces following error:
> 'Failed to add dependency on "a@*.service", ignoring: Invalid
argument'
>
>
> I use also a Before=b.service statement for a at .service but that is not
> enough.
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