Petter Reinholdtsen

Entries tagged "bootsystem".

Debian boots quicker and quicker
2009-06-24 21:40

I spent Monday and tuesday this week in London with a lot of the people involved in the boot system on Debian and Ubuntu, to see if we could find more ways to speed up the boot system. This was an Ubuntu funded developer gathering. It was quite productive. We also discussed the future of boot systems, and ways to handle the increasing number of boot issues introduced by the Linux kernel becoming more and more asynchronous and event base. The Ubuntu approach using udev and upstart might be a good way forward. Time will show.

Anyway, there are a few ways at the moment to speed up the boot process in Debian. All of these should be applied to get a quick boot:

These points are based on the Google summer of code work done by Carlos Villegas.

Support for makefile-style concurrency during boot was uploaded to unstable yesterday. When we tested it, we were able to cut 6 seconds from the boot sequence. It depend on very correct dependency declaration in all init.d scripts, so I expect us to find edge cases where the dependences in some scripts are slightly wrong when we start using this.

On our IRC channel for this effort, #pkg-sysvinit, a new idea was introduced by Raphael Geissert today, one that could affect the startup speed as well. Instead of starting some scripts concurrently from rcS.d/ and another set of scripts from rc2.d/, it would be possible to run a of them in the same process. A quick way to test this would be to enable insserv and run 'mv /etc/rc2.d/S* /etc/rcS.d/; insserv'. Will need to test if that work. :)

Tags: bootsystem, debian, english.
Taking over sysvinit development
2009-07-22 23:00

After several years of frustration with the lack of activity from the existing sysvinit upstream developer, I decided a few weeks ago to take over the package and become the new upstream. The number of patches to track for the Debian package was becoming a burden, and the lack of synchronization between the distribution made it hard to keep the package up to date.

On the new sysvinit team is the SuSe maintainer Dr. Werner Fink, and my Debian co-maintainer Kel Modderman. About 10 days ago, I made a new upstream tarball with version number 2.87dsf (for Debian, SuSe and Fedora), based on the patches currently in use in these distributions. We Debian maintainers plan to move to this tarball as the new upstream as soon as we find time to do the merge. Since the new tarball was created, we agreed with Werner at SuSe to make a new upstream project at Savannah, and continue development there. The project is registered and currently waiting for approval by the Savannah administrators, and as soon as it is approved, we will import the old versions from svn and continue working on the future release.

It is a bit ironic that this is done now, when some of the involved distributions are moving to upstart as a syvinit replacement.

Tags: bootsystem, debian, english, nuug.
Debian has switched to dependency based boot sequencing
2009-07-27 23:50

Since this evening, with the upload of sysvinit version 2.87dsf-2, and the upload of insserv version 1.12.0-10 yesterday, Debian unstable have been migrated to using dependency based boot sequencing. This conclude work me and others have been doing for the last three days. It feels great to see this finally part of the default Debian installation. Now we just need to weed out the last few problems that are bound to show up, to get everything ready for Squeeze.

The next step is migrating /sbin/init from sysvinit to upstart, and fixing the more fundamental problem of handing the event based non-predictable kernel in the early boot.

Tags: bootsystem, debian, english, nuug.
Parallellizing the boot in Debian Squeeze - ready for wider testing
2010-05-06 23:25

These days, the init.d script dependencies in Squeeze are quite complete, so complete that it is actually possible to run all the init.d scripts in parallell based on these dependencies. If you want to test your Squeeze system, make sure dependency based boot sequencing is enabled, and add this line to /etc/default/rcS:

CONCURRENCY=makefile

That is it. It will cause sysv-rc to use the startpar tool to run scripts in parallel using the dependency information stored in /etc/init.d/.depend.boot, /etc/init.d/.depend.start and /etc/init.d/.depend.stop to order the scripts. Startpar is configured to try to start the kdm and gdm scripts as early as possible, and will start the facilities required by kdm or gdm as early as possible to make this happen.

Give it a try, and see if you like the result. If some services fail to start properly, it is most likely because they have incomplete init.d script dependencies in their startup script (or some of their dependent scripts have incomplete dependencies). Report bugs and get the package maintainers to fix it. :)

Running scripts in parallel could be the default in Debian when we manage to get the init.d script dependencies complete and correct. I expect we will get there in Squeeze+1, if we get manage to test and fix the remaining issues.

If you report any problems with dependencies in init.d scripts to the BTS, please usertag the report to get it to show up at the list of usertagged bugs related to this.

Tags: bootsystem, debian, english.
systemd, an interesting alternative to upstart
2010-05-13 22:20

The last few days a new boot system called systemd has been introduced to the free software world. I have not yet had time to play around with it, but it seem to be a very interesting alternative to upstart, and might prove to be a good alternative for Debian when we are able to switch to an event based boot system. Tollef is in the process of getting systemd into Debian, and I look forward to seeing how well it work. I like the fact that systemd handles init.d scripts with dependency information natively, allowing them to run in parallel where upstart at the moment do not.

Unfortunately do systemd have the same problem as upstart regarding platform support. It only work on recent Linux kernels, and also need some new kernel features enabled to function properly. This means kFreeBSD and Hurd ports of Debian will need a port or a different boot system. Not sure how that will be handled if systemd proves to be the way forward.

In the mean time, based on the input on debian-devel@ regarding parallel booting in Debian, I have decided to enable full parallel booting as the default in Debian as soon as possible (probably this weekend or early next week), to see if there are any remaining serious bugs in the init.d dependencies. A new version of the sysvinit package implementing this change is already in experimental. If all go well, Squeeze will be released with parallel booting enabled by default.

Tags: bootsystem, debian, english, nuug.
Parallellized boot is now the default in Debian/unstable
2010-05-14 22:40

Since this evening, parallel booting is the default in Debian/unstable for machines using dependency based boot sequencing. Apparently the testing of concurrent booting has been wider than expected, if I am to believe the input on debian-devel@, and I concluded a few days ago to move forward with the feature this weekend, to give us some time to detect any remaining problems before Squeeze is frozen. If serious problems are detected, it is simple to change the default back to sequential boot. The upload of the new sysvinit package also activate a new upstream version.

More information about dependency based boot sequencing is available from the Debian wiki. It is currently possible to disable parallel booting when one run into problems caused by it, by adding this line to /etc/default/rcS:

CONCURRENCY=none

If you report any problems with dependencies in init.d scripts to the BTS, please usertag the report to get it to show up at the list of usertagged bugs related to this.

Tags: bootsystem, debian, debian edu, english.
Parallellized boot seem to hold up well in Debian/testing
2010-05-27 23:55

A few days ago, parallel booting was enabled in Debian/testing. The feature seem to hold up pretty well, but three fairly serious issues are known and should be solved:

All in all not many surprising issues, and all of them seem solvable before Squeeze is released. In addition to these there are some packages with bugs in their dependencies and run level settings, which I expect will be fixed in a reasonable time span.

If you report any problems with dependencies in init.d scripts to the BTS, please usertag the report to get it to show up at the list of usertagged bugs related to this.

Update: Correct bug number to file-rc issue.

Tags: bootsystem, debian, debian edu, english.
KDM fail at boot with NVidia cards - and no one try to fix it?
2010-06-01 17:05

It is strange to watch how a bug in Debian causing KDM to fail to start at boot when an NVidia video card is used is handled. The problem seem to be that the nvidia X.org driver uses a long time to initialize, and this duration is longer than kdm is configured to wait.

I came across two bugs related to this issue, #583312 initially filed against initscripts and passed on to nvidia-glx when it became obvious that the nvidia drivers were involved, and #524751 initially filed against kdm and passed on to src:nvidia-graphics-drivers for unknown reasons.

To me, it seem that no-one is interested in actually solving the problem nvidia video card owners experience and make sure the Debian distribution work out of the box for these users. The nvidia driver maintainers expect kdm to be set up to wait longer, while kdm expect the nvidia driver maintainers to fix the driver to start faster, and while they wait for each other I guess the users end up switching to a distribution that work for them. I have no idea what the solution is, but I am pretty sure that waiting for each other is not it.

I wonder why we end up handling bugs this way.

Tags: bootsystem, debian, debian edu, english.
Upstart or sysvinit - as init.d scripts see it
2010-06-06 23:55

If Debian is to migrate to upstart on Linux, I expect some init.d scripts to migrate (some of) their operations to upstart job while keeping the init.d for hurd and kfreebsd. The packages with such needs will need a way to get their init.d scripts to behave differently when used with sysvinit and with upstart. Because of this, I had a look at the environment variables set when a init.d script is running under upstart, and when it is not.

With upstart, I notice these environment variables are set when a script is started from rcS.d/ (ignoring some irrelevant ones like COLUMNS):

DEFAULT_RUNLEVEL=2
previous=N
PREVLEVEL=
RUNLEVEL=
runlevel=S
UPSTART_EVENTS=startup
UPSTART_INSTANCE=
UPSTART_JOB=rc-sysinit

With sysvinit, these environment variables are set for the same script.

INIT_VERSION=sysvinit-2.88
previous=N
PREVLEVEL=N
RUNLEVEL=S
runlevel=S

The RUNLEVEL and PREVLEVEL environment variables passed on from sysvinit are not set by upstart. Not sure if it is intentional or not to not be compatible with sysvinit in this regard.

For scripts needing to behave differently when upstart is used, looking for the UPSTART_JOB environment variable seem to be a good choice.

Tags: bootsystem, debian, english.
Automatic upgrade testing from Lenny to Squeeze
2010-06-11 22:50

The last few days I have done some upgrade testing in Debian, to see if the upgrade from Lenny to Squeeze will go smoothly. A few bugs have been discovered and reported in the process (#585410 in nagios3-cgi, #584879 already fixed in enscript and #584861 in kdebase-workspace-data), and to get a more regular testing going on, I am working on a script to automate the test.

The idea is to create a Lenny chroot and use tasksel to install a Gnome or KDE desktop installation inside the chroot before upgrading it. To ensure no services are started in the chroot, a policy-rc.d script is inserted. To make sure tasksel believe it is to install a desktop on a laptop, the tasksel tests are replaced in the chroot (only acceptable because this is a throw-away chroot).

A naive upgrade from Lenny to Squeeze using aptitude dist-upgrade currently always fail because udev refuses to upgrade with the kernel in Lenny, so to avoid that problem the file /etc/udev/kernel-upgrade is created. The bug report #566000 make me suspect this problem do not trigger in a chroot, but I touch the file anyway to make sure the upgrade go well. Testing on virtual and real hardware have failed me because of udev so far, and creating this file do the trick in such settings anyway. This is a known issue and the current udev behaviour is intended by the udev maintainer because he lack the resources to rewrite udev to keep working with old kernels or something like that. I really wish the udev upstream would keep udev backwards compatible, to avoid such upgrade problem, but given that they fail to do so, I guess documenting the way out of this mess is the best option we got for Debian Squeeze.

Anyway, back to the task at hand, testing upgrades. This test script, which I call upgrade-test for now, is doing the trick:

#!/bin/sh
set -ex

if [ "$1" ] ; then
    desktop=$1
else
    desktop=gnome
fi

from=lenny
to=squeeze

exec < /dev/null
unset LANG
mirror=http://ftp.skolelinux.org/debian
tmpdir=chroot-$from-upgrade-$to-$desktop
fuser -mv .
debootstrap $from $tmpdir $mirror
chroot $tmpdir aptitude update
cat > $tmpdir/usr/sbin/policy-rc.d <<EOF
#!/bin/sh
exit 101
EOF
chmod a+rx $tmpdir/usr/sbin/policy-rc.d
exit_cleanup() {
    umount $tmpdir/proc
}
mount -t proc proc $tmpdir/proc
# Make sure proc is unmounted also on failure
trap exit_cleanup EXIT INT

chroot $tmpdir aptitude -y install debconf-utils

# Make sure tasksel autoselection trigger.  It need the test scripts
# to return the correct answers.
echo tasksel tasksel/desktop multiselect $desktop | \
    chroot $tmpdir debconf-set-selections

# Include the desktop and laptop task
for test in desktop laptop ; do
    echo > $tmpdir/usr/lib/tasksel/tests/$test <<EOF
#!/bin/sh
exit 2
EOF
    chmod a+rx $tmpdir/usr/lib/tasksel/tests/$test
done

DEBIAN_FRONTEND=noninteractive
DEBIAN_PRIORITY=critical
export DEBIAN_FRONTEND DEBIAN_PRIORITY
chroot $tmpdir tasksel --new-install

echo deb $mirror $to main > $tmpdir/etc/apt/sources.list
chroot $tmpdir aptitude update
touch $tmpdir/etc/udev/kernel-upgrade
chroot $tmpdir aptitude -y dist-upgrade
fuser -mv

I suspect it would be useful to test upgrades with both apt-get and with aptitude, but I have not had time to look at how they behave differently so far. I hope to get a cron job running to do the test regularly and post the result on the web. The Gnome upgrade currently work, while the KDE upgrade fail because of the bug in kdebase-workspace-data

I am not quite sure what kind of extract from the huge upgrade logs (KDE 167 KiB, Gnome 516 KiB) it make sense to include in this blog post, so I will refrain from trying. I can report that for Gnome, aptitude report 760 packages upgraded, 448 newly installed, 129 to remove and 1 not upgraded and 1024MB need to be downloaded while for KDE the same numbers are 702 packages upgraded, 507 newly installed, 193 to remove and 0 not upgraded and 1117MB need to be downloaded

I am very happy to notice that the Gnome desktop + laptop upgrade is able to migrate to dependency based boot sequencing and parallel booting without a hitch. Was unsure if there were still bugs with packages failing to clean up their obsolete init.d script during upgrades, and no such problem seem to affect the Gnome desktop+laptop packages.

Tags: bootsystem, debian, debian edu, english.

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