X-Git-Url: http://pere.pagekite.me/gitweb/homepage.git/blobdiff_plain/0bfca3b9c82e95b306eb58737f021ddd42c3eae5..70f990418b5d050f8a4d6be7c0d6b6ed3ee5d90f:/blog/archive/2010/05/index.html diff --git a/blog/archive/2010/05/index.html b/blog/archive/2010/05/index.html index 6afc607fe9..db4711f9ac 100644 --- a/blog/archive/2010/05/index.html +++ b/blog/archive/2010/05/index.html @@ -112,6 +112,285 @@ change.

+
+
+ 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: 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: debian, english, nuug. + +
+
+
+ +
+
+ Sitesummary tip: Listing MAC address of all clients +
+
+ 2010-05-14 21:10 +
+ +
+ +

In the recent Debian Edu versions, the +sitesummary +system 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.

+ +

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:

+ +
+perl -MSiteSummary -e 'for_all_hosts(sub { print join(" ", get_macaddresses(shift)), "\n"; });'
+
+ +

This will list all MAC addresses assosiated with all machine, one +line per machine and with space between the MAC addresses.

+ +

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.

+ +
+
+ + + + Tags: debian, debian edu, english, sitesummary. + +
+
+
+ +
+
+ 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: debian, debian edu, english. + +
+
+
+ +
+
+ Pieces of the roaming laptop puzzle in Debian +
+
+ 2010-05-19 19:00 +
+ +
+ +

Today, the last piece of the puzzle for roaming laptops in Debian +Edu finally entered the Debian archive. Today, the new +libpam-mklocaluser +package was accepted. Two days ago, two other pieces was accepted +into unstable. The +pam-python +package needed by libpam-mklocaluser, and the +sssd package +passed NEW on Monday. In addition, the +libpam-ccreds +package we need is in experimental (version 10-4) since Saturday, and +hopefully will be moved to unstable soon.

+ +

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 BTS report +#485282 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.

+ +

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.

+ +

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.

+ +

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.

+ +

If you want to help out with implementing this for Debian Edu, +please contact us on debian-edu@lists.debian.org.

+ +
+
+ + + + Tags: debian edu, english, nuug. + +
+
+
+

RSS Feed

@@ -132,7 +411,7 @@ change.

  • April (3)
    • -
  • May (1)
    • +
  • May (6)
    • @@ -187,11 +466,11 @@ change.

  • aros (1)
    • -
  • debian (14)
    • +
  • debian (18)
    • -
  • debian edu (15)
    • +
  • debian edu (18)
    • -
  • english (24)
    • +
  • english (29)
  • fiksgatami (1)
    • @@ -207,7 +486,7 @@ change.

  • norsk (64)
    • -
  • nuug (71)
    • +
  • nuug (73)
  • opphavsrett (12)
    • @@ -219,6 +498,8 @@ change.

  • sikkerhet (7)
    • +
  • sitesummary (1)
    • +
  • standard (11)
  • stavekontroll (1)