X-Git-Url: http://pere.pagekite.me/gitweb/homepage.git/blobdiff_plain/0bfca3b9c82e95b306eb58737f021ddd42c3eae5..70f990418b5d050f8a4d6be7c0d6b6ed3ee5d90f:/blog/archive/2010/05/05.rss diff --git a/blog/archive/2010/05/05.rss b/blog/archive/2010/05/05.rss index b16b324e26..86d986f856 100644 --- a/blog/archive/2010/05/05.rss +++ b/blog/archive/2010/05/05.rss @@ -85,5 +85,219 @@ change.</p> + + Parallellizing the boot in Debian Squeeze - ready for wider testing + http://people.skolelinux.org/pere/blog/Parallellizing_the_boot_in_Debian_Squeeze___ready_for_wider_testing.html + http://people.skolelinux.org/pere/blog/Parallellizing_the_boot_in_Debian_Squeeze___ready_for_wider_testing.html + Thu, 6 May 2010 23:25:00 +0200 + +<p>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 +<a href="http://wiki.debian.org/LSBInitScripts/DependencyBasedBoot">dependency +based boot sequencing</a> is enabled, and add this line to +/etc/default/rcS:</p> + +<blockquote><pre> +CONCURRENCY=makefile +</pre></blockquote> + +<p>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.</p> + +<p>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. :)</p> + +<p>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.</p> + +<p>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 +<a href="http://bugs.debian.org/cgi-bin/pkgreport.cgi?users=initscripts-ng-devel@lists.alioth.debian.org">the +list of usertagged bugs related to this</a>.</p> + + + + + systemd, an interesting alternative to upstart + http://people.skolelinux.org/pere/blog/systemd__an_interesting_alternative_to_upstart.html + http://people.skolelinux.org/pere/blog/systemd__an_interesting_alternative_to_upstart.html + Thu, 13 May 2010 22:20:00 +0200 + +<p>The last few days a new boot system called +<a href="http://www.freedesktop.org/wiki/Software/systemd">systemd</a> +has been +<a href="http://0pointer.de/blog/projects/systemd.html">introduced</a> + +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 +<a href="http://upstart.ubuntu.com/">upstart</a>, and might prove to be +a good alternative for Debian when we are able to switch to an event +based boot system. Tollef is +<a href="http://bugs.debian.org/580814">in the process</a> 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.</p> + +<p>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.</p> + +<p>In the mean time, based on the +<a href="http://lists.debian.org/debian-devel/2010/05/msg00122.html">input +on debian-devel@</a> 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.</p> + + + + + Sitesummary tip: Listing MAC address of all clients + http://people.skolelinux.org/pere/blog/Sitesummary_tip__Listing_MAC_address_of_all_clients.html + http://people.skolelinux.org/pere/blog/Sitesummary_tip__Listing_MAC_address_of_all_clients.html + Fri, 14 May 2010 21:10:00 +0200 + +<p>In the recent Debian Edu versions, the +<a href="http://wiki.debian.org/DebianEdu/HowTo/SiteSummary">sitesummary +system</a> is used to keep track of the machines in the school +network. Each machine will automatically report its status to the +central server after boot and once per night. The network setup is +also reported, and using this information it is possible to get the +MAC address of all network interfaces in the machines. This is useful +to update the DHCP configuration.</p> + +<p>To give some idea how to use sitesummary, here is a one-liner to +ist all MAC addresses of all machines reporting to sitesummary. Run +this on the collector host:</p> + +<blockquote><pre> +perl -MSiteSummary -e 'for_all_hosts(sub { print join(" ", get_macaddresses(shift)), "\n"; });' +</pre></blockquote> + +<p>This will list all MAC addresses assosiated with all machine, one +line per machine and with space between the MAC addresses.</p> + +<p>To allow system administrators easier job at adding static DHCP +addresses for hosts, it would be possible to extend this to fetch +machine information from sitesummary and update the DHCP and DNS +tables in LDAP using this information. Such tool is unfortunately not +written yet.</p> + + + + + Parallellized boot is now the default in Debian/unstable + http://people.skolelinux.org/pere/blog/Parallellized_boot_is_now_the_default_in_Debian_unstable.html + http://people.skolelinux.org/pere/blog/Parallellized_boot_is_now_the_default_in_Debian_unstable.html + Fri, 14 May 2010 22:40:00 +0200 + +<p>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 +<a href="http://lists.debian.org/debian-devel/2010/05/msg00122.html">input +on debian-devel@</a>, 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.</p> + +More information about +<a href="http://wiki.debian.org/LSBInitScripts/DependencyBasedBoot">dependency +based boot sequencing</a> 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:</p> + +<blockquote><pre> +CONCURRENCY=none +</pre></blockquote> + +<p>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 +<a href="http://bugs.debian.org/cgi-bin/pkgreport.cgi?users=initscripts-ng-devel@lists.alioth.debian.org">the +list of usertagged bugs related to this</a>.</p> + + + + + Pieces of the roaming laptop puzzle in Debian + http://people.skolelinux.org/pere/blog/Pieces_of_the_roaming_laptop_puzzle_in_Debian.html + http://people.skolelinux.org/pere/blog/Pieces_of_the_roaming_laptop_puzzle_in_Debian.html + Wed, 19 May 2010 19:00:00 +0200 + +<p>Today, the last piece of the puzzle for roaming laptops in Debian +Edu finally entered the Debian archive. Today, the new +<a href="http://packages.qa.debian.org/libp/libpam-mklocaluser.html">libpam-mklocaluser</a> +package was accepted. Two days ago, two other pieces was accepted +into unstable. The +<a href="http://packages.qa.debian.org/p/pam-python.html">pam-python</a> +package needed by libpam-mklocaluser, and the +<a href="http://packages.qa.debian.org/s/sssd.html">sssd</a> package +passed NEW on Monday. In addition, the +<a href="http://packages.qa.debian.org/libp/libpam-ccreds.html">libpam-ccreds</a> +package we need is in experimental (version 10-4) since Saturday, and +hopefully will be moved to unstable soon.</p> + +<p>This collection of packages allow for two different setups for +roaming laptops. The traditional setup would be using libpam-ccreds, +nscd and libpam-mklocaluser with LDAP or Kerberos authentication, +which should work out of the box if the configuration changes proposed +for nscd in <a href="http://bugs.debian.org/485282">BTS report +#485282</a> is implemented. The alternative setup is to use sssd with +libpam-mklocaluser to connect to LDAP or Kerberos and let sssd take +care of the caching of passwords and group information.</p> + +<p>I have so far been unable to get sssd to work with the LDAP server +at the University, but suspect the issue is some SSL/GnuTLS related +problem with the server certificate. I plan to update the Debian +package to version 1.2, which is scheduled for next week, and hope to +find time to make sure the next release will include both the +Debian/Ubuntu specific patches. Upstream is friendly and responsive, +and I am sure we will find a good solution.</p> + +<p>The idea is to set up the roaming laptops to authenticate using +LDAP or Kerberos and create a local user with home directory in /home/ +when a usre in LDAP logs in via KDM or GDM for the first time, and +cache the password for offline checking, as well as caching group +memberhips and other relevant LDAP information. The +libpam-mklocaluser package was created to make sure the local home +directory is in /home/, instead of /site/server/directory/ which would +be the home directory if pam_mkhomedir was used. To avoid confusion +with support requests and configuration, we do not want local laptops +to have users in a path that is used for the same users home directory +on the home directory servers.</p> + +<p>One annoying problem with gdm is that it do not show the PAM +message passed to the user from libpam-mklocaluser when the local user +is created. Instead gdm simply reject the login with some generic +message. The message is shown in kdm, ssh and login, so I guess it is +a bug in gdm. Have not investigated if there is some other message +type that can be used instead to get gdm to also show the message.</p> + +<p>If you want to help out with implementing this for Debian Edu, +please contact us on debian-edu@lists.debian.org.</p> + + +