I’ve been evaluating Passenger for a while now and I’ve generally been pleased. I find that an Apache + Passenger setup has been easier to manage than alternative Rails stacks. Performance has been good and memory consumption has been lessened which also helps performance on the systems in general. However I have seen some strange bugs while using my web apps under Passenger. I am hoping that this upgrade will resolve these issues. The upgrade was relatively easy and the steps I took follows.

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: