Maybe it’s just my perception but I feel that backports for Ubuntu 8.04 haven’t been particularly forthcoming. These are the requested backports and updates that I would take advantage of should they become available.

• libgems-ruby 1.1.1
• k3b 1.0.5
• smplayer 0.6.0
• swfdec 0.6.6 backport
• swfdec 0.6.6 update

I suppose that growing a RAID 1 array is not very common but I had a client that wanted to go from a 2 disk array to a 3 disk array so that one disk could be rotated out periodically and kept off-site. Here were the steps:

• mdadm --add /dev/mdX /dev/sdXX
  • This adds the partition to the array as a hot spare.
• mdadm --grow /dev/mdX -n 3
  • This increases the number of disks from 2 to 3.

I’ve been reading through the launchpad bugs for Xen and thought that I could use them to illustrate some tips and tricks for using Xen in Ubuntu or Debian. I ran into some problems with Xen today on a system after having been upgraded from Ubuntu 7.10 to Ubuntu 8.04 and from Xen 3.1 to Xen 3.2. This should help as a checklist when diagnosing various Xen problems.

Although this version of rubygems should show up in hardy-backports I’m not sure it will ever be ported to gutsy-backports. So I decided to pull the new version and install it on my Ubuntu 7.10 (Gutsy Gibbon) systems. I had previously been using 1.0.1 from Debian testing. The steps to install were quite simple. This should work for at least ubuntu 7.10 and 8.04 and perhaps other versions as well.

A new kernel, 2.6.24-17, has been released for Ubuntu 8.04 (Hardy Heron) in the hardy-updates repository. This kernel may fix at least 1 xen bug (bug 218126, bug 204010) which I’m anxious to test. I’ve held off upgrading any Xen user domains until these were resolved. I think it would be a good time to at least test an upgrade, and since virtualization makes it easy to rollback I think a test is in order. I also noticed that Ubuntu 7.10 got some new kernel modules in the gutsy-updates repository. Not sure what the changes are but it’s something to be aware of.

I recently tried the reniced package only to find that it isn’t a daemon at all as is indicated by its name ending in “d”. It’s too bad because if it was it could be useful. It could always be called frequently from cron in order to have a system that continuously adjusts the niceness of running processes. The config file is pretty nice as it’s just a list of a nice level pair with a regular expression to match against the list of processes. This can be useful to change the niceness of processes launched without any other mechanism for controlling the nice level. I found that running firefox and kvm with a niceness of 10 can keep either from making the rest of the system too unresponsive.

I've been evaluating both Gnash and Swfdec for a few weeks. I've come to the conclusion that Swfdec is the superior software. Far more Flash content works with Swfdec than Gnash. However, Swfdec still hsa the same problem it had under Ubuntu 7.10 (Gutsy Gibbon): it uses a full processor core when displaying Flash video. I spend some time today trying to track down the problem but was unsuccessful. It has been noted that the problem only seems to occur when using Swfdec through a browser such as Firefox or Epiphany. When I was looking at process cpu utilization I noticed that sometimes the browser would be consuming the CPU but other times it would be X using a large number of cycles. That, combined with the fact that not everyone seems to suffer from this issue, leads me to think there is a configuration issue responsible. However, no amount of changing the X configuration on my system made any difference. Still, video is usually still watchable using Swfdec though it does stutter a bit. And Swfdec's compatibility with other Flash content is much higher than Gnash. I would certainly recommend Swfdec over Gnash or Adobe's Flash player for Ubuntu 8.04.

I spent a few hours this weekend trying to test KDE 4 in Ubuntu only to find it unusable. I tried to different virtual machines but both had the same problem: immediately after logging in the session ends and returns to the login screen. I spent longer than I'd care to admit trying to resolve the problem but to no avail. I was able to find reports of similar behavior but no useful solutions. I think I may just give up on KDE 4 until the 4.1 version is released and made available.

I’ve been evaluating the versions of Gnash and SWFdec that are included with Ubuntu 8.04 (Hardy Heron) and it took me a while to figure out how to switch between them. The /etc/alternatives directory has 7 links for flash plugins. The correct command for Firefox 3 is:

• sudo update-alternatives --config xulrunner-addons-flashplugin

This allows the user to select Gnash or SWFdec for Flash playback in Ubuntu 8.04.

When helping people to upgrade to Ubuntu 8.04 I find myself doing the same post-installation tasks on many setups. Here are some of those tasks, to be updated with more later perhaps. But removing old kernels, installing java, installing flash, and removing cruft are all common and useful tasks following an upgrade.

Over time, especially with Ubuntu and it’s 6 month release cycle, a system can contain a number of packages that are no longer needed but still present on the system in some way. I have a number of techniques I use to locate these packages and remove them and I thought I would share them.

I really liked VirtualBox and got a lot of use out of it when running my old Windows XP system under Ubuntu. However, the lack of support for 64-bit systems proved too problematic. In testing Ubuntu 8.04 (Hardy Heron) I was only interested in testing the 64-bit versions as that was all I would be running. As some bugs are architecture dependent (iproute and monsterz come to mind) it's important to perform testing on the architecture you will actually use. Under Ubuntu 7.10 (Gutsy Gibbon) I had some issues with QEMU and KVM though I was able to use them enough to do testing (though often only through QEMU with specific parameters at a less than ideal speed). However in Ubuntu 8.04 I found both applications improved and decided to search for a nice front-end to replace the functionality I was used to with VirtualBox.

I often find myself asking the same questions about package dependencies. It can sometimes be confusing to remember which command answers which question due to the similarity of the commands. These are the common questions:

Despite my best efforts there is still no graphical SILC client in Ubuntu. I feel I’ve commented on my frustration and disappointment with this fact enough in the past. So, here’s how to get SILC working through Pidgin in Ubuntu 8.04.

I wanted to finally explore the various tools for creating graphs of Rails models. I’ve been wanting to do so for a while because such graphs can really help when developing an application. I really wanted something that was a gem and not a plugin and I found that Railroad was just what I was looking for. Rails Application Visualizer seems to have been abandoned and is a plugin and Visualize Models is also a plugin. Here’s how I installed and used Railroad.

I’ve compiled a partial list of threads from ubuntuforums describing problems caused by sudo breaking when upgrading to Ubuntu 8.04 (Hardy Heron) in order to strengthen the case that this is a serious bug that should be resolved immediately.

Obviously I’m a fan of Ubuntu as I run it on my laptop, desktop, and even a number of servers (both physical and virtual). That can’t deter me from being critical of the Hardy Heron release. I can sympathize with the difficulty of the task of releasing a stable OS every 6 months. Perhaps that is simply an unrealistic goal. Or perhaps this is just a stage of growing pains for a new OS. I watched launchpad during the beta testing of Hardy Heron and saw the number of bugs being reported. Having a new bug report every 2-3 minutes accumulates a large number of reports for people to examine and remedy. And I suspect that’s where Canonical will have to increase its effort. The success is that so many people are contributing bug reports. The failure is that so few have been resolved, including some fairly critical ones that I will mention in detail.

Here are some of the applications with available packages for Debian and Ubuntu:

• AIDE
• FCheck
• Integrit
• Samhain
• Stealth
• Tripwire

I’m leaning toward trying Stealth because I like the design. Lots of folks seem to like FCheck for its simplicity.

I was interested in trying to determine how many packages were installed from universe on the servers I manage. Luckily I came across a helpful discussion titled list installed Universe packages which suggested this command:

• comm -12 <(apt-cache dumpavail | grep-dctrl -nsPackage -FSection universe/ |sort) <(dpkg --get-selections | awk '$2 == "install" { print $1 }' |sort)

To get the command to work I had to install the package dctrl-tools (for the grep-dctrl command):

• sudo apt-get install dctrl-tools

After that it worked pretty well and can easily be adapted to search for other sections. It turns out that my servers use many packages from universe but none from restricted or multiverse, which is nice.

Just a few days ago Passenger was released in order to better integrate Rails with Apache. I decided to give it a try as I see it being very useful to simplify Rails deployments. I was also interested in testing the performance compared to nginx and mongrel.