Fedora 18 features an installer that is rewritten and redesigned from the ground up. This summary is meant to help you understand why the installer has been rewritten, what improvements the new installer will bring, what to expect when you work with the new installer, and some known issues with the installer that will be resolved in later releases of Fedora.
Why rewrite the installer?
After many years of maintaining and developing the pre-Fedora 18 installer, the installer development team determined that a rewrite of the installer was necessary for a myriad of reasons, including the following:
- The previous installer had an aging (around 13 years old) infrastructure that was difficult and time-consuming to maintain and improve, constraining new feature development. One current install team developer refers to the old infrastructure as "an incredible mess."
- The performance of the old installer left a lot to be desired. Long-term tasks could not be performed in the background. This required long wait times and pauses throughout the installation experience. For example, as CPU and time-intensive tasks were processed, the UI would freeze for several moments until a given processing task completed.
- The previous UI was not very responsive. This manifested in various ways, including a failure of the UI screens to redraw when the display was changed between a TTY and back to the UI.
- The text-only version of the installer interface was a completely separate codebase, which increased the maintenance burden of the installer. This also increased the amount of work needed to implement new features as they would need to be written twice, once for each codebase.
- The previous codebase was not written in a modular fashion. This caused issues where similar functionality in different modes (for example, GUI vs kickstart) used different logic and resulted in inconsistencies for users.
- The automated kickstart mode of the installer was separate and incompatible with the UI modes of the installer. A separate utility, system-config-kickstart, was created solely to provide a UI for creating kickstarts since the existing UI could not be used for this purpose without a completed install.
- The live media method of installation used a different codepath than the installer than the DVD method, causing maintenance and development difficulties and resulting in an inconsistent and at times buggy user experience.
- The old installer's interface had a 'point of no return' past which any changes you'd made to your storage configuration could destroy data on your disk(s) and you couldn't go back to change it. Since the UI followed a linear path, this exact inflection point occurred close to the middle of the screen flow and required a rather discouraging pop-up dialog to explain the impact.
- In previous versions of Fedora, the installer's interface followed a wizard design pattern , consisting of multiple linear screens with occasional nested modal pop-up dialogs. (See diagram below) While nothing is inherently problematic with wizards as a design pattern, the sheer number of screens required by the installer made it unwieldy. You could end up several screens into the process and need to go back and change something on an earlier screen, requiring a lot of clicking and screen flipping to go back and return to where you left off. Multiple modal nested dialog windows also made it confusing at times to interact with certain screens, in particular the partitioning-related screens.
New installer improvements in Fedora 18
In order to address these and other issues, the installer development team changed the UI model from a linear wizard-based model to a hub and spoke model. Essentially, the installer UI has been distilled into two main menus, from which you can optionally visit various option screens. Each menu list out each sub-screen and summarizes the choices selected for each sub-screen so you can skip screens that you don't need to configure if you'd like. See the diagram below for a visual illustration of how the hub and spoke model works.
The new installer available in Fedora 18 addresses a number of issues that were difficult to solve in the old codebase:
- The new installer is written in a modular fashion, so there aren't multiple copies of code that does the same thing scattered around the codebase.
- Long-running tasks can be performed in the background as you use the installer. For example, when you first start the installer and land on the first screen for language selection, the installer is - in the background - attempting to auto-detect your network settings and set up a network connection for you.
- The UI of the new installer has been written in such a way that it does not block and freeze up while waiting for CPU and time-intensive tasks to process.
- The new installer is primarily based on kickstart, whether or not you are using the automated & unattended kickstart option to install, the text user interface, or the graphic user interface. All three, in addition to the live media installation method, share a common codebase, providing a more consistent experience across installation methods as well as a more easily-maintained codebase. Eventually, the plan is to auto-detect any kickstart files available to a system during install and offer to pre-fill the fields in the UI with the values in the kickstart to help save users time.
- With the change to a hub-and-spoke model rather than a linear wizard model, the new UI allows users to entirely skip screens that they aren't interested in interacting with, streamlining the install process to only those screens that are most essential for installation to proceed.
- When the feature is completed for Fedora 19, the new installer will allow you to complete firstboot while the installer downloads and installs Fedora to your computer, helping to further streamline the install process. If you opt to not complete firstboot during installation, it will appear after you reboot the system.
What to expect when using the new installer
Known installer issues
Please refer to the Common_F18_bugs page for information on single specific bugs (there is useful information on several particular installer bugs here, and we recommend that you read it before installing Fedora 18). This section will concentrate on more generic issues, mainly features that are missing or incomplete in Fedora 18 due to lack of development time but will be improved or restored in Fedora 19.
Enterprise storage technologies missing from interactive installation
Support for some enterprise storage features is missing from the interactive installer interface in Fedora 18. This includes technologies like multipath and FCoE: generally speaking, if you had to use the 'Specialized Storage Devices' screen in Fedora 17 and earlier, your setup may not be supported in the Fedora 18 interactive installer. Kickstart-based installs can use these features as always. The missing support will be added back for Fedora 19.
Custom partitioning does not handle some complex configurations
The custom partitioning tool in Fedora 18 is able to handle a wide range of storage cases, including various raw partition formats, LVM, LUKS encryption, software RAID, btrfs, and various combinations. However, it was not possible in the time available to ensure that every possible advanced configuration combining these supported technologies was handled. If you have a complex storage configuration which does not appear to be handled correctly by the new installer, possible workarounds including using a kickstart, or in some cases preparing the drive with a partition tool like parted before installing Fedora. Please be aware that it is safe to experiment as much as you like with the partitioning screens in the new installer: no actual changes will be written to disk until you return to the hub screen and click the Begin Installation button. If you are not confident that you were able to achieve your desired configuration, you can simply reboot the system at any time before clicking that button and no changes will have been made.
Repository configuration limitations
The options for repository configuration during interactive Fedora 18 installation are significantly more limited than in previous releases. This is again a temporary result of time pressure and will be rectified for future releases.
- It is not possible to specify additional supplementary repositories. You can of course choose the main repository location for any installation, but you cannot specify an incomplete supplementary repository containing a few additional or updated packages.
- It is not possible to configure which set of repositories any given installation will use. A DVD installation will always install only packages from the DVD itself; it cannot be supplemented with remote repositories. A network installation will always install packages from the fedora and updates repositories, and never from the updates-testing repository.
As in other cases, these restrictions do not apply to Kickstart-based installations: as in the past, you can specify any combination of repositories using a kickstart file.
As part of the changes for the new installer, some hard-coded information about various internationalization (i18n hereafter) scenarios was removed. The long-term plan is that such information should be provided in some more appropriate forum - ideally some kind of distribution-neutral, upstream project where any application (an OS installer or otherwise) which might be able to benefit from it could use it. However, in the short term, it means that the i18n experience in Fedora 18 may not be quite as polished as that in earlier releases. Specifically:
- The names of languages and locations on the Welcome screen are taken from the CLDR database. In some cases these may not reflect real-world use as well as the tweaked list of names used previously. For instance, those who read and write Simplified Chinese typically use the zh_CN locale wherever they live, and those who read and write Traditional Chinese typically use the zh_TW locale: in previous Fedora releases, these locales were labelled Chinese (Simplified) and Chinese (Traditional) to reflect this. Based on the CLDR database, they are now labelled geographically as Chinese (China) and Chinese (Taiwan).
- Previous Fedora releases offered only a subset of possible keyboard layouts to the user at installation time, but each of these options was tweaked to produce an optimal configuration. When you selected one of the keyboard types the installer knew about, it configured an appropriate console layout and X keyboard layout: in cases where users typically configure both a 'native' and a U.S. layout and switch between them in order to enter both 'native' and Roman characters, the installer would configure both X layouts and a keyboard combination to switch between them. The new installer does not have this special knowledge any more: the Keyboard spoke simply allows you to configure any combination of all the X layouts available in Fedora, and any layout switch combination you like if you configure more than one. This is more flexible, but requires a little more work and knowledge on the user's part.