[OE-core] RFE: make the init manager an image feature (again)

[Enrico Scholz]

Hello,

it would be nice when the decision to make the init manager a distribution
feature will be reverted to the old oe-meta mechanism.

Being a distribution feature means, that packages are created in such a
way that it is impossible to split off unwanted and heavy weighted
functionality at image creation time.

E.g. on most of my systems, I create two kinds of images: a full
featured, systemd based one and a very minimal rescue system with
busybox and some filesystem utilities.  With recent systemd packaging
change, the rescue image size grow up from 5.9 MiB to 27 MiB because
systemd dependencies are hardcoded in mandatory packages.

Formerly, systemd dependencies could be avoided by adding the -systemd
packages to BAD_RECOMMENDATIONS (e.g. due to busybox-syslog ->
busybox-syslog-systemd rrecommend).

I am aware that initscripts were always part of the main package.  But
sysvinit was very lightweighted and the extra space either negligible or
easy to recover by removing some files in IMAGE_PREPROCESS_COMMAND.

Hence my recommendation: make the init manager an image feature again
and create -systemd and -sysv packages with the corresponding scripts.
OpenEmbedded is still for embedded devices where size matters.


Of course, systemd can be still a distribution feature to enable things
like socket activation as part of PACKAGE_CONFIG.  But dependencies on
init system packages should be RRECOMMENDS which can be overridden
easily at image creation time.



Enrico