[node-devel] Introduction and migration of the ovirt-node SysV init scripts to systemd

[Fabian Deutsch]

Hey,

I'm new to this list a just want to quickly introduce myself. My name is
Fabian Deutsch (fabiand), I'm 29yrs of age and live near Bremen in
Germany. Currently I'm maintaining a couple of packages and using
libvirt and friends within our working group to maintain a couple of
virtual guests.

Coming to ovirt-node I saw that the init scripts are in the SysV/LSB
format, but it makes sense to migrate them - like the init scripts of
all daemons - to systemd.
Because the scripts ain't trivial I would like to discuss the migration
before.

First it seems if the affected files are ovirt and ovirt-awake,
ovirt-early, and ovirt-firstboot in the scripts directory.
Besides fulfilling the SysV requirements by providing start(), stop()
etc. those files also contain much logic to setup and check ovirt
specific things.
But it's essential to pull the logic out of the init scripts, to allow a
migration to systemd service files, which usually just call an
appropriate daemon or - like in our case - oneshot scripts.

Therefor I'm suggesting to split the SysV stuff from the logic in a
first step while keeping SysV init files.
After this step we would have reduced SysV init scripts, containing just
the relevant SysV stuff and a bunch of scripts residing in
e.g. /usr/libexec/ovirt which provide the logic and are used by the init
scripts to do the magic.

The second step would then be to replace the reduced init scripts by
appropriate systemd service files.

A last step could be migrating the init scripts to python, in order to
consolidate some code.

One problem I could imagine is, that the scripts currently export some
global variables and I don't to whom they will visible when using
systemd files - or if there is no change in the behavior at all.

Does the migration and the suggested steps make sense? 
Or am I missing something?

Greetings
fabian