Public SourceMage Discussion List

[flux <flux AT sourcemage.org>]

Thomas Orgis (thomas-forum AT orgis.org) wrote [11.08.04 20:08]:
> Man, I'd really like to see proper castfs usage: As staging environment for 
> the whole cast, multiple casts even. For self-conflicts, and in the course 
> of multiple casts into the staging environment, stuff needs only be removed 
> for the build environment (castfs), not for the live system. Merges of 
> casts into the real system should happen in bulk form on demand by the 
> admin ... having similar dangerousness as normal upgrade of binary distros.
> 
> But well, we've had this suggestion several times in the past and what's 
> missing is someone to implement it. But I'm not that one. Not this year. 
> Just as last year:-/ Still, it strikes me as odd that other SMGL folks 
> don't seem to see this as such a major issue as I do. Is everyone using a 
> dual rootfs approach* to prevent casts from forcing downtime on machines? 
> How do you update your SMGL servers? 
> 
> I have a faint memory that such a staging thingie is standard in gentoo ... 
> but I'd have to research into that again. It should be a standard feature 
> of source-based distros, though.
> 
> 
> Alrighty then,
> 
> Thomas.
> 
> 
> * Which is a rather extreme approach at the cast staging ... a whole real 
> filesystem for updates, quick merge via rsync or such ... or just reboot 
> into the other fs. Then do updates in the first fs. Loop.

I would like to see this as well, but as an option (and as the default
of that option). Ideally sorcery should support bare staging (chucking
the whole install into a plain temp directory without using a fuse
filesystem), staging with castfs (or unionfs -- what's happening with
this one?), or doing no staging at all (our current default). Either
way, what we have now isn't real staging, since it only stages BUILD,
not INSTALL (or perhaps even FINAL, depending on what a given spell is
doing in FINAL). Then rather than STAGING being only on or off, it could
have specific values (plain, casts, none/off, etc.), and it could always
grow more options if more were needed.

Staging the install is more expensive, but what's the point of staging?
Is it not to ensure system integrity? If we agree that's the purpose of
staging, then I think Thomas makes excellent points (btw: in the older
days when I actually used Gentoo, they did do full staging, and on the
bare filesystem (i.e. the "plain" option).

I personally just don't do updates that often, and am careful when I do
them. For critical systems and critical spells, I'd always update in a
chroot first and test it, and then migrate from the chroot to the live
system afterwards.

-- 
Justin "flux_control" Boffemmyer
Cauldron wizard and general mage
Source Mage GNU/Linux
http://www.sourcemage.org

Attachment: pgp6J9ezhHb0k.pgp
Description: PGP signature