From: Martin Steigerwald <martin@lichtvoll.de>
To: "Theodore Ts'o" <tytso@mit.edu>
Cc: Harald Hoyer <harald@redhat.com>, Richard Weinberger <richard@nod.at>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [GIT PULL] kdbus for 4.1-rc1
Date: Wed, 29 Apr 2015 18:25:12 +0200
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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
GPG: 03B0 0D6C 0040 0710 4AFA  B82F 991B EAAC A599 84C7
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