fedup for F23 and beyond

[Petr Hracek]

On 05/28/2015 05:42 PM, Will Woods wrote:
> [tl;dr: fedup is going away and should be re-implemented by the system
> packaging tools.]
>
> Hey all,
>
> F22 is the fifth release we've handled with fedup. A lot has changed
> since F17, and we've learned some valuable lessons about how upgrades
> work (and how they fail).
>
> We've come to the conclusion that the current design is unsupportable,
> mostly due to upgrade.img, which turns out to cause more problems than
> it solves[1].
>
> So! For F23, fedup needs to be redesigned. Here's how it should work:
>
> 1) Download packages for the new system
> 2) Use the systemd Offline Updates[2] facility to install packages
Does it mean that using systemd Offline Updates there will not be a 
"Zero" downtime feature.
Except rebooting because of kernel upgrade?

Will there be any possibility to inform user if API or ABI issues are 
discovered after an upgrade?
E.g Database was changed and needs to be fixed after the upgrade?

>
> This is really simple - simple enough that it should probably be
> provided by the system packaging tools themselves.
>
> As a proof-of-concept, I've implemented it as a DNF plugin, which you
> can see here[3]: https://github.com/wgwoods/dnf-plugin-fedup
>
> This behavior could also be implemented by PackageKit, which would make
> it easy to write a proper GUI.
QT and GUI for upgrade would be awesome?
Do you have any draft already?
>
> So that's the plan: drop upgrade.img, move upgrade support into the
> system packaging tools. Sometimes simpler is better.
>
> -w
>
> [1] For example, here are three F22 release-blockers, all caused by
> upgrade.img:
>    https://bugzilla.redhat.com/show_bug.cgi?id=1185604
>    https://bugzilla.redhat.com/show_bug.cgi?id=1209941
>    https://bugzilla.redhat.com/show_bug.cgi?id=1207251
> That first one is a nasty crash inside systemd, which led to a
> mailing-list discussion[1a] where Lennart concludes that the
> double-switchroot thing we're doing with upgrade.img is just not
> supportable[1b]. And I totally agree.
> [1a] http://lists.freedesktop.org/archives/systemd-devel/2015-March/029030.html
> [1b] http://lists.freedesktop.org/archives/systemd-devel/2015-April/031013.html
> [2] http://www.freedesktop.org/wiki/Software/systemd/SystemUpdates/
> [3] It works just fine in F21, if you're feeling brave..
>


-- 
Petr Hracek
Software Engineer
Developer Experience
Red Hat, Inc
Mob: +420777056169
email: phracek at redhat.com