Fedora 7: Custom Spins with Revisor

The tool for creating custom images is called pungi, and the tool for creating live images is called livecd-creator. Both of these are command-line tools which leverage the existing Fedora software infrastructure, including the anaconda installer, yum package management system, and kickstart installation-description file.

A graphical front-end has been created for all of these tools, named revisor.
This tool makes it relatively easy to spin a custom installation or live image -- all it takes is a few clicks, a lot of disk space, and plenty of time.

Installing revisor installs the required pungi and livecd-tools packages plus all of their dependencies. Revisor itself can then be started using the menu option Applications>System Tools>Revisor (Gnome menu location).

After a splash screen, revisor invites you to select the images you wish to build: installation images for DVD or CD or live images for optical disk (whether it fits on a CD or requires a DVD will depend on the amount of software chosen) or USB drives. You can select several options and have them built in a single session. Today I'll focus on the installation image options.

The next page enables you to select the revisor configuration file to be used, the configuration section (distribution) to be used, the destination directory, and the repositories. When you first start using revisor you'll probably want to start with the default configuration file, which offers F7, FC6, and Rawhide (development) sections for various architectures. If you change the configuration section, click the Apply button to update the repository list. The destination directory field appears to be ignored at present.

Although you should be able to build images for any architecture on any arcitecture, the current state of the system requires that you build on the same type of system that you are targetting: that is, if you want a PPC image, you should build it on a PPC system.

Traditionally, Fedora has used kickstart files for automating the selection of installation options, making it easy to select the partitioning, network configuration, authentication options, root password, package selection, and so forth for new systems without asking the user any questions. In fact, a kickstart file is created during any normal installation, and this file can be reused to install other systems with the same options.

Pungi, livecd-tools, and revisor all use the kickstart format for configuring image builds. Obviously some kickstart options such as partitioning are ignored, but some options such as package selection apply equally to image creation and installation, so it makes sense to use the same file format for both purposes.

The next revisor screen asks for the kickstart configuration file to be used. The default file is a reasonable choice for experimentation. Three other checkbox options are presented:

• Use package manifest from kickstart data - when checked (the default), the package set will be take from the kickstart file instead of promping you.
• Customize package manifest defined in kickstart data - when checked along with the previous option, you will be given the opportunity to adjust the package set manually. In other words, selecting neither of these two options will present a GUI for package selection; selecting both of them will do the same, but the default package selection will be taken from the kickstart file.
• Customize/review additional options loaded from kickstart data - this mainly applies to live image creation, where options such as starting in runlevel 5 or 3 (GUI or no GUI) need to be selected.

Select the package categories and groups that you want using the left and right panes, and use the Optional packages button to add or remove optional packages within each package group. Alternately, you can use the List or Search tabs to select packages by name.

Once you have selected the packages for your image, revisor will present a confirmation screen which will, in a later version, offer additional options. Clicking Forward will start the build process -- a good time to take a leisurely lunch. Or two, depending on the speed of your system, the number of packages selected, and the repository and network supplying those packages (later this week I'll talk about using a local repository).

Revisor keeps you well-informed of progress during the image build process, but it does not estimate completion time. Once the image has been created, it will tell you the name of the directory containing the results. The actual ISO images will be contained in a directory several levels below the name reported by revisor; the easiest way to burn them to disc is to find each image using Nautilus (or Konqueror for KDE users), right-click on it, and select "Write to disc".

If the program stops during the image-building process, it's usually due to lack of disk space, and revisor doesn't always produce a clear error message describing this problem. Check the space available on your filesystems, especially the one containing /var/tmp, before starting revisor and if you run into problems.

Revisor is a fantastic tool, making the capabilities of pungi easily accessible. It's obviously in a fairly early stage of development, as indicated by the number of grayed-out and unimplemented options displayed, but it does it job and it does it well.

Up next: Using Revisor to create Live Images. (Yes, the schedule for the week is completely shot -- my apologies! -- but there will still be five postings).