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New Installer: Live Installation

Ladislav Slezák edited this page Oct 16, 2013 · 1 revision

Live Installation

Live installation is part of SLES and openSUSE for a few years; apart of openSUSE, it has its role in deploying of live images based on SLES, which are built in SUSE Studio.

The live image creator can allow to trigger the live installer directly via bootloader option, as it is done in openSUSE, or only start it from the desktop or console.

Since the live image runs as a full-blown operating system and not only a minimal inst-sys, the memory requirements may be higher than for standard installation. On the other hand, some parts of the installer, which are normally located in RAM disk, can be read directly from the media (e.g. CD or DVD disk).

Boot new machine

The live image is booted via standard boot mechanism; the live installer does not provide any dedicated booting procedure and relies on the underlying system.

However, the installer must be able to start in a fully running system, with applications possibly running. This may have impact on the memory requirements of live installation.

The live installer must be able to prepare its environment (e.g. make sure that X11 is running) as well as be started from desktop or console.

Installation Wizard

In general, this part of the workflow does not need to differ from regular installation workflow any significantly. However, it may make sense to skip some of the options and assume that user has already configured them (e.g. network configuration). This also matches the intention to have the same system running (meaning especially regarding configuration) after installation of the image as before the installation.

Since the live system comes as a preinstalled set of packages, software selection (and therefore also registration) is not entirely necessary for deploying the image. However, registration (which drags in also software repositories) allows the installer to modify the package selection during the installation. Whether it should be possible or not can be decided by the creator of the image and should be configurable for the installer, however, the installer should be ready for this option.

TODO: Analyze steps which can be removed from live installation wizard.

Deployment

The deployment part will differ mostly from the regular deployment procedure. While some parts can be reused (e.g. disk partitioning), some must be implemented independently (dump of current system from the running live image to hard disk).

If decided by the image creator that modifying package selection is possible, the image deployment step also needs to reinitialize the software stack (or at least the target part) so that package installation can continue.

TODO: Analyze all steps which take part of deployment and make sure that the deployment step does everything needed, e.g.

  • Needed config file updates (e.g. fstab needed by package post-scripts)
  • Bootloader configuration is ready for kernel installation Most of these can be reviewed from inst_kickoff and other scripts run before package installation starts during regular installation.

Apply Config

There will be no substantial change compared to regular installation. However, parts which will not be configured during the wizard step should also be skipped here.

FirstBoot

No changes compared to regular installation, will remain optional.