RE: [docs] [OE-core] is "poky" distro defined to use "sysvinit" as INIT_MANAGER?

[Peter Kjellerstedt <peter.kjellerstedt@axis.com>]

> -----Original Message-----
> From: docs@lists.yoctoproject.org <docs@lists.yoctoproject.org> On Behalf
> Of Richard Purdie
> Sent: den 5 januari 2023 15:57
> To: Michael Opdenacker <michael.opdenacker@bootlin.com>
> Cc: OE Core mailing list <openembedded-core@lists.openembedded.org>; Khem
> Raj <raj.khem@gmail.com>; Robert P. J. Day <rpjday@crashcourse.ca>; YP
> docs mailing list <docs@lists.yoctoproject.org>
> Subject: Re: [docs] [OE-core] is "poky" distro defined to use "sysvinit"
> as INIT_MANAGER?
> 
> On Thu, 2023-01-05 at 15:23 +0100, Michael Opdenacker wrote:
> > Am 03.01.23 um 15:41 schrieb Michael Opdenacker via
> lists.openembedded.org:
> > > Hello Richard,
> > >
> > > Trying to improve the documentation about the selection of the init
> > > system, I'm jumping back to this old conversation, following a change
> > > that you made (https://lists.yoctoproject.org/g/poky/message/12760).
> > >
> > > Am 06.07.22 um 18:40 schrieb Khem Raj:
> > > > On Wed, Jul 6, 2022 at 12:38 PM Robert P. J. Day
> > > > <rpjday@crashcourse.ca> wrote:
> > > > >
> > > > >    not sure why i never noticed this before, but i started a new
> > > > > project from the poky layer (not OE), and realized that poky.conf
> > > > > explicitly sets:
> > > > >
> > > > >    INIT_MANAGER = "sysvinit"
> > > > >
> > > > > which can't be overridden in my local.conf. if i want systemd, i guess
> > > > > i can initialize my project from the OE layer, and i also notice that
> > > > > i could use poky-altcfg.conf.
> > > > >
> > > > >    but is there a reason that the default poky-based project fixes
> > > > > INIT_MANAGER to "sysvinit". perhaps just for simplicity?
> > > > >
> > > > poky defaults to sysvinit.
> > > > poky has poky-alt distro fi you want to use say systemd
> > >
> > > But why not setting INIT_MANAGER with "?=" instead of "=" in poky.conf?
> > >
> > > This way, we could just override INIT_MANAGER from local.conf.
> > >
> > > I checked that the generated system works. This would make things
> > > easier to document, unless I'm missing other reasons.
> >
> >
> > Richard told me on IRC that, from memory, this was set because of
> > interference poky-altcfg (if I understood correctly).
> >
> > I understand one recommended way to have systemd instead of sysvinit in
> > Poky is to use "poky-altcfg" instead of "poky" as distro.

I am not sure using poky-altcfg as an alternative to using poky + systemd 
is a good suggestion since poky-altcfg changes a couple of other settings as 
well (see meta-poky/conf/distro/include/poky-distro-alt-test-config.inc).

> >
> > Similarly, I guess I should use "poky-tiny" if I want to use
> > "mdev-busybox" as INIT_MANAGER.
> >
> > Then, I guess I'll document something like this:
> >
> >   * With the OpenEmbedded build system, you can choose your init system
> >     by setting INIT_MANAGER to "sysvinit", "systemd", "busybox-mdev" or
> >     "none"
> >   * BUT if you're using Poky, that won't work, so your options will be
> >     to use either "poky" (sysvinit), "poky-altcfg" (systemd) or
> >     "poky-tiny" (mdev-busybox).
> >
> > Does this sound like the right way to document this?
> 
> We should really fix poky so this works correctly. I just have a memory
> of trying to fix it and it not being as straightforward it first
> appears. I'd then have got distracted by the next problem :/
> 
> Cheers,
> 
> Richard

You can of course override it in your local.conf, but it requires to use an 
override, e.g., INIT_MANAGER:poky = "systemd" should work if you are in fact 
using the poky distro.

However, since the recommendation typically is to use your own distro if you 
are doing more serious changes (like, e.g., using another init manager than 
the default one), this should normally not be a problem. In the simplest case 
you can create a distro like:

require conf/distro/poky.conf

INIT_MANAGER = "systemd"

and you are then better off than doing this kind of changes in your 
local.conf.

//Peter