On Mon, 2019-04-22 at 09:25 -0700, Adam Williamson wrote: > On Sat, 2019-04-20 at 07:59 +0000, Zbigniew Jędrzejewski-Szmek wrote: > > On Fri, Apr 19, 2019 at 04:35:54PM -0400, John Florian wrote: > > > I'm generally familiar with how systemd presets work but I'm at a > > > bit of loss as to how part of all the magic works. To best explain > > > my confusion, let me say that I make a customized live spin of > > > Fedora and I have a package we'll call "my-dist" which is similar in > > > nature to the "fedora-release" package in that it provides a custom > > > preset file. I still use fedora-release because this spin is not > > > *that* customized, so it's best to think of this as an extension. I > > > have another package we'll call "my-service" which has a systemd > > > service unit file and all the usual %systemd_post, etc. macros. > > > When I boot my live spin I find that my-service is not enabled > > > despite the preset in my-dist. I can "systemctl preset-all" to > > > rectify this so I believe most requirements are correct. I do see > > > that livemedia-creator installs my-service *before* it installs > > > my-dist so if the %systemd_post is called as each rpm is installed > > > that would explain my problem because my custom preset isn't present > > > yet. > > > > > > How does Fedora itself accomplish this??? I don't see every package > > > providing a service having a dependency on fedora-release to address > > > this ordering issue. I can certainly stick the "systemctl > > > preset-all" into the %post of my kickstart as final cleanup, but > > > that feels dirty and wrong. Similarly, I don't wish to have to have > > > a "Requires: my-dist" in every one of "my-service" and other > > > packages like it. I've scrutinized fedora-release.spec and didn't > > > see anything all that different than what I have in my-dist. > > > > systemd.rpm does preset-all when it is installed, so it is enough > > that systemd.rpm is installed after fedora-release-common.rpm. > > fedora-release-common is required by setup.rpm, so it is installed > > early. But you raise a good point — I don't see any *explicit* > > ordering chain between fedora-release-common and systemd. > > > > There is no need to order individual rpms against either > > fedora-release-common and other packages providing presets or > > systemd. The only thing that is necessary is for systemd.rpm to be > > installed after all presets. If that is satisfied, packages proving > > services can be installed both earlier and later and the effect > > (in the sense of service enablement) should be identical. > > AIUI, the design is that any package that *ships a preset* should run > systemctl preset on it in its scriptlets (there should be guidelines > for this somewhere but I can't find them right now). However, there's a > loophole here in that if any package that ships a preset gets ordered > before systemd itself during install, its attempt to run 'systemctl > preset' will obviously fail. This is why we run 'preset-all' in the > systemd package scriptlets: to apply the presets for any packages which > were already installed. It's not intended that all other packages can > *rely* on the call in systemd's scripts. BTW if you're wondering "why not just make sure everything that ships a preset gets installed after systemd"...sadly there are some awkward cases that make that not practical, basically 'systemd depends on something that installs a preset' or 'systemd depends on something that depends on something that installs a preset'. -- Adam Williamson Fedora QA Community Monkey IRC: adamw | Twitter: AdamW_Fedora | XMPP: adamw AT happyassassin . net http://www.happyassassin.net _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
