Kees Cook: yay for barriers

Posted May 18, 2010 18:37 UTC (Tue) by ewan (guest, #5533)
In reply to: Kees Cook: yay for barriers by mjthayer
Parent article: Kees Cook: yay for barriers

As people have said it often works well with just yum, but the recommended route is still to run the anaconda installation program, but that is far, far short of a re-install. If you use preupgrade you only download the packages you need, your configuration files and data are kept, but the upgrade itself runs from within a temporary anaconda system, not on the live running OS.

That helps to avoid some of the difficulties that live upgrades can encounter (even on Debian) but still gives most of the advantages.

Kees Cook: yay for barriers

Posted May 18, 2010 19:17 UTC (Tue) by mjthayer (guest, #39183) [Link] (3 responses)

> As people have said it often works well with just yum, but the recommended route is still to run the anaconda installation program, but that is far, far short of a re-install.

That answers my question rather well. The most important point for me there is that the result of the upgrade is the same as a Debian-style upgrade and not like a clean install. That was not quite clear to me from skimming the Fedora documentation, and seemed, shall we say, rather surprising to me.

How much of the upgrade requires taking the system offline? Can the new system be built up while the old one is running and (more or less) just restarted into once the upgrade is done?

Kees Cook: yay for barriers

Posted May 18, 2010 19:36 UTC (Tue) by paulj (subscriber, #341) [Link]

FWIW, I have systems where I don't even fully upgrade them. I just make sure rpm/yum are upgraded, update the fedora-release, and then I use just "yum --security update-minimal" to update only the stuff that has to be updated. E.g.:

$ rpm -qa --qf '%{RELEASE}\n' | sed -e 's/^.*[.]//' | grep ^f | sort -u
fc10
fc7
fc8
fc9
fc11

How's that? :)

Kees Cook: yay for barriers

Posted May 18, 2010 20:45 UTC (Tue) by cry_regarder (subscriber, #50545) [Link] (1 responses)

Yes. yum upgrade does this. After it is done, you may have some checking for orphans to do, especially if you have custom packages.

preupgrade is just like a dvd upgrade but it doesn't require you to burn media to reboot into. It does a bunch of work while the system is online, then when you are ready, you trigger the offline upgrade. In my experience, you are looking at maybe an hour offline depending on the machine and internet connection.

Cry

Kees Cook: yay for barriers

Posted May 19, 2010 8:07 UTC (Wed) by michich (guest, #17902) [Link]

preupgrade is just like a dvd upgrade but it doesn't require you to burn media to reboot into.

There's one more difference and it's even more important: preupgrade takes post-release updates into account:

preupgrade takes you from (F<n> + F<n>-updates) to (F<n+1> + F<n+1>-updates), which is great.
DVD upgrade takes you from (F<n> + F<n>-updates) to F<n+1> only, which is broken by design.

In my experience the methods to upgrade a Fedora installation ordered from the most reliable to the least reliable are:

yum update in a running system (BUT one must know what he's doing and must read http://fedoraproject.org/wiki/YumUpgradeFaq!)
preupgrade (It's very easy to use and requires almost no thinking. I only put it in the second place because I encountered bugs in the past, fixed since then.)
(separated by a large margin:) using anaconda from the DVD

Note that I realize well that official documentation disagress with me.