> > On Wed, Jul 02, 2003 at 03:18:36PM +0800, Niall Young wrote:
> > I'm using a custom package pool for deploying software, but we need to
> > cleanly rollback if an upgrade doesn't go as expected.
> In easy cases it is possible to first test a package with some testing
> machine and only put in in the used archive when it suites your needs.
Agreed, I meant in *addition* to pre-deployment testing - say if testing
didn't pick up all bugs and you discover fatal problems post deployment.
> > How about a postrm::downgrade hook to reverse any changes made in the
> > new version's preinst::upgrade so that when the old version's
> > preinst::upgrade
> > is applied you're not left with a potential mix of configuration?
> > seamlessly - i.e. reverse all changes made in the upgrade. Is there
> > another way?
> You'd need more than that. Apt would need to be changed to handle
> undoing of package splitting (Conflicts/Replaces), and is not always
> possible anyway, new packages, might use new file-formats which can be
> converted from the old-version but not back again.
Yeah - it's a minefield of nightmares I know. Debian handles upgrades
really well, but downgrades aren't as seamless. A postrm::downgrade
hook is a pretty major change, it would take years to roll out - just
wondering if anyone has thought about the problem before and if/when
Debian could address this? A remove and clean install seems to be the only
option which is unfortunate. Something to think about at least...
Niall Young Chime Communications Pty Ltd
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Ph: (+61) 08 9213 1330 / 0408 192 797 Perth, Western Australia 6000
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-- Jodie Evans, Feb 2003