Upgrade & Rollback

FIXME

Overview

FIXME

• imgbased for management of versioned filesystem layers

• Layout

  • liveimg is rsynced into Thin LV, then made RO and active=n (BASE)
  • Thin snapshot of LV is created, this is RW (LAYER)
  • Boot entry for RW thin snapshot (LAYER) is created

• Upgrade

  • New BASE with new LAYER is created
  • Rsync /etc from old LAYER to new LAYER
  • Set primary boot entry to new LAYER

• Rollback

  • Set primary boot entry to old LAYER

Assumptions

FIXME

• /etc is on LAYER
• /var is on separate volume

Open Items

• How do driver disks survive an upgrade?
• uid drift is solved enough?
• daemon for imgbased
• currently kernel+initrd are in subdir in /boot, idea: keep kernel+initrd in /boot. This will allow dracut and others to work correctly

Package persistence

FIXME

• should rpms be persisted? if so, how?
  • separate volume with magic name, put rpm there, will be reinstalled on every new layer
  • only through puppet/chef/ansible?
  • yum plugin to record and cache installed pkgs on separate vol?

Delivery

FIXME

• squashfs wrapped in rpm
• "dnf download" rpm on the host
• extract squashfs from the rpm
• then use imgbase to upgrade