Re: systemd, again (Re: Cinnamon environment now available in testing)
On Sat, Sep 06, 2014 at 09:39:05AM -0700, Russ Allbery wrote:
> Note also that a few of those things (udev, adduser, and
> libdevmapper1.02.1 for example) are likely to be on any non-chroot system
> already since they're either dependencies of other things (such as grub
> for libdevmapper1.02.1) or are already in use regardless of the init
> system (udev). So for the case of a small embedded system that's
> nonetheless running the full kernel + bootloader stack, I suspect the
> delta is even smaller.
I can give a hard data point. A month ago, debootstrap in Jessie was
still giving you a sysvinit based system. I build a VM that has a
minimal debootstrap, with a very small set of packages[1], plus
xfstests. In early August, this VM was 54 megabytes
[1] https://git.kernel.org/cgit/fs/ext2/xfstests-bld.git/tree/kvm-xfstests/test-appliance/packages
This past weekend, I spent a good part of the weekend updating
kvm-xfstests to use systemd, since debootstrap now forces systemd on
you, and so I decided to bite the bullet and convert to systemd.
This was not quite trivial, because I depended on being able to run
xfstests in /etc/rc.local, and serial console getty would start up
before /etc/rc.local had finished, and then HUP the entier xfstests
run. Still, after fighting with the sysvinit unit scripts, I finally
managed to get it all working again.
The resulting VM image was 62 megabytes[2], or about 15% larger.
Since the VM image generation is completely automated[3], I'm
confident that this is an apples-to-apples comparison.
[2] https://www.kernel.org/pub/linux/kernel/people/tytso/kvm-xfstests/
[3] https://git.kernel.org/cgit/fs/ext2/xfstests-bld.git/tree/kvm-xfstests/test-appliance/gen-image
Cheers,
- Ted
P.S. Note what is required to be fully GPL compliant when
distributing a VM image[4]. You need to be able to identify the
precise sources for *all* of the GPL'ed packages used for a particular
VM image, and it's something that most people don't bother to do. To
(loosely) quote Bradley Kuhn from his recent talk at LinuxCon, "it's
all too easy to accidentally violate the GPL; I'm sure I've done it
from time to time".
[4] ftp://ftp.kernel.org/pub/linux/kernel/people/tytso/kvm-xfstests/README
Reply to: