Re: [GIT PULL] kdbus for 4.1-rc1

Martin Steigerwald
2015-04-29T16:25:17Z

Am Mittwoch, 29. April 2015, 11:03:41 schrieb Theodore Ts'o:
> On Wed, Apr 29, 2015 at 04:53:53PM +0200, Harald Hoyer wrote:
> > Sure, I can write one binary to rule them all, pull out all the code
> > from all tools I need, but for me an IPC mechanism sounds a lot
> > better. And it should be _one_ common IPC mechanism and not a
> > plethora of them. It should feel like an operating system and not
> > like a bunch of thrown together software, which is glued together
> > with some magic shell scripts.
>
> And so requiring wireshark (and X?) in initramfs to debug problems
> once dbus is introduced is better?
>
> I would think shell scripts are *easier* to debug when things go
> wrong, especially in a minimal environment such as an initial ram
> disk. Having had to debug problems in a distro initramfs when trying
> to help a customer bring up a FC boot disk long ago in another life,
> I'm certain I would rather debug problems while on site at a
> classified machine room[1] using shell scripts, and trying to debug
> dbus is something that would be infinitely worse.

Later in boot process I have seen some debugging issues with a systemd
governed userspace:

Bug 1213778 - drops into emergency mode without any error message if it
cannot find a filesystem in /etc/fstab
https://bugzilla.redhat.com/show_bug.cgi?id=1213778

Bug 1213781 - does not start ssh service if a filesystem in /etc/fstab
cannot be mounted
https://bugzilla.redhat.com/show_bug.cgi?id=1213781

With shell scripts I had error messages for these, here I had to browse
the output of journalctl -xb to find out.

And then what do I do if dbus communication is not working for some
reason? Will I then be able to use journalctl at all?

Not that proper error reporting can´t be added in systemd and the
dependency handling can´t be fixed towards some more sanity like for
example "no /boot mount, no worries, I still start that ssh service for
you", but currently for me this is a clear and heavy regression when I
compare this with sysvinit boot behavior.

I do fix things when being dropped to initramfs shell, I added some script
snippet for supporting BTRFS RAID 1 while it wasn´t yet supported in
Debian (dunno if it is for booting in Jessie, but as my bug reports have
not been closed yet, maybe bot), I still want to be able to do these kinds
of things.

Ciao,
--
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
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