Saturday, November 06, 2010

Remastering Ubuntu Mini Remix

Ubuntu Mini Remix is a very small, very efficient Ubuntu distribution created by Fabrizio Balliano. I discovered it when I needed to create a kiosk-like boot disk image that booted the user directly into a simple command-line application. I didn't need X Windows, OpenOffice, web access, or email, I just needed to run my application, and UMR was perfect for that. The baseline UMR image is about 165 MB, and is available for i386 and for amd64.

In my previous blog post, I explained how to create a debian package. Since then I've written a shell script that takes one or more debian packages and uses them to remaster UMR. If you wanted to use the debian package from the last blog post to update UMR, you could simply type:
(cd ../make-debian-pkg/; make)
./customize.sh \
    ../make-debian-pkg/foo-bar_1.0_i386.deb
If you have multiple debian packages to be included, simply add them as additional command line arguments. The result will be a file called "customized-umr-10.10-i386.iso", located in your home directory.

For very small additions, a package may be overkill. It might make better sense to edit the script to simply add the files you need, and in my situation at work, that was the approach I ultimately chose. But if your change is more substantial, and especially if you want to include other packages that you'll rely upon, you'll want to think about using package management.

If you want your boot image to take the user directly into your application as I did, you can go into the chroot jail and replace the file /etc/skel/.bashrc with a short script that calls your application. The command would look like this:
sudo cp my-bashrc ${CHROOT_JAIL}/etc/skel/.bashrc
and you'd want to put that with the lines where the comment says "Prepare to chroot", near line 63. (Take the line number with a grain of salt as I may end up editing it at some point.)

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