Overview of the Leapp Live Mode workflow

Updated -

The live-mode procedure is basically the same than the standard Leapp upgrade as described in our documentation. For now, this feature is available only for 8>9 upgrades as an EXPERIMENTAL / TECH-PREVIEW feature. For now, this feature is also restricted to the x86_64 architecture.

The live-mode-config-scanner actor

Executed if LEAPP_UNSUPPORTED=1 during the FactsCollectionPhase.
If it exists, it reads /etc/leapp/actor.d/livemode.yaml and produces LiveModeConfigFacts.
With the default values, it will boot locally.

Configuration options

Configuration option Value type Description
url_to_load_squashfs_from string Url pointing to the squashfs image. if not set, the upgrade will boot locally. example: "http://192.168.122.1/live-upgrade.img"
squashfs_fullpath string Path to where the squashfs image should be stored
dracut_network string Dracut network arguments. Required if the url_to_lead_squashfs_from is set. example1: "ip=dhcp". example2: "ip=192.168.122.146::192.168.122.1:255.255.255.0:foo::none"
setup_network_manager bool Enable the NetworkManager
additional_packages str List of extra packages to include in the target userspace. example: "pk1,pkg2,pkg3"
autostart_upgrade_after_reboot bool Autostart the upgrade upon reboot
setup_opensshd_with_auth_keys str Setup SSHD using the given path to authorized keys file. If empty, SSHD will not be enabled. example: "/root/.ssh/authorized_keys"
capture_upgrade_strace_into str File into which leapp upgrade service's strace output will be written. If empty, leapp will not be run under strace. example: "/var/lib/leapp/upgrade.strace"
setup_passwordless_root bool Setup passwordless root for the live image used during the upgrade. Use with caution

The emit-livemode-userspace-requirements actor

  • intervene during the InterimPreparationPhase, and consumes the UsedTargetRepositories (among others).
  • assume the standard packages to build an initramfs have already been installed by the upgrade_initramfs_generator actor.
  • the requirements like dracut-live and dracut-squash to build a live image into the container, are now installed by the upgrade_initramfs_generator (via the dnfplugin).
  • also install some reporting or debugging tools (strace, kexec-tools, lspci, lsscsi, ...).
  • produce a LiveModeRequirementsTasks.

The prepare-live-image actor

  • intervene later as it consumes the LiveModeRequirementsTasks.
  • create a dedicated fstab with xfs/ext entries prepended by /run/initramfs/live (the default mount point for dmsquash-live).
  • install the do-upgrade.sh script (slightly modified) as a systemd upgrade.service, logs are then sent to the journal.
  • a console.service puts the output of tail -f leapp-upgrade.log on tty1, and agetty are spawned on tty2-tty4. A remaining autovt is left for a serial connection (e.g. ttyS0).
  • some customizations are performed at this step (no passwd for the root account, setup sshd, write a banner...).
  • then it creates the initramfs-upgrade image with the dmsquash-live and dracut-squash dracut modules.
  • note: the original Leapp dracut modules are not used anymore.
  • finally produce a PrepareLiveImageTasks.

The live-image-generator actor

  • intervene at the very end of the InterimPreparationPhase.
  • consume LiveModeConfigFacts, PrepareLiveImageTasks, PrepareLiveImagePostTasks (unused) and produce LiveModeArtifacts.
  • the target userspace is then squashed into /var/lib/leapp/live-upgrade.img.

Modifications of the addupgradebootentry actor

The kernel cmdline is prepared and then grubby is called:

  • problematic parameters for the live mode are removed: ro, rd.lvm.lv (and also rhgb quiet).
  • the root parameter is defined by default for a local boot: root=live:<UUID> where <UUID> is the one from the partition where live-upgrade.img resides. It is used alongside rd.live.dir and rd.live.squashimg.
  • note: the root parameter can be changed by the "url" parameter from the livemode.yaml config file: root=live:<URL> (e.g. url=http://192.168.122.1/live-upgrade.img).

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