[Pacemaker] [RFC] [Patch] DC node preferences (dc-priority)

[Lars Ellenberg]

On Fri, May 25, 2012 at 09:05:54PM +1000, Andrew Beekhof wrote:
> On Fri, May 25, 2012 at 7:48 PM, Florian Haas <florian at hastexo.com> wrote:
> > On Fri, May 25, 2012 at 11:38 AM, Lars Ellenberg
> > <lars.ellenberg at linbit.com> wrote:
> >> On Fri, May 25, 2012 at 11:15:32AM +0200, Florian Haas wrote:
> >>> On Fri, May 25, 2012 at 10:45 AM, Lars Ellenberg
> >>> <lars.ellenberg at linbit.com> wrote:
> >>> > Sorry, sent to early.
> >>> >
> >>> > That would not catch the case of cluster partitions joining,
> >>> > only the pacemaker startup with fully connected cluster communication
> >>> > already up.
> >>> >
> >>> > I thought about a dc-priority default of 100,
> >>> > and only triggering a re-election if I am DC,
> >>> > my dc-priority is < 50, and I see a node joining.
> >>>
> >>> Hardcoded arbitrary defaults aren't that much fun. "You can use any
> >>> number, but 100 is the magic threshold" is something I wouldn't want
> >>> to explain to people over and over again.
> >>
> >> Then don't ;-)
> >>
> >> Not helping, and irrelevant to this case.
> >>
> >> Besides that was an example.
> >> Easily possible: move the "I want to lose" vs "I want to win"
> >> magic number to be 0, and allow both positive and negative priorities.
> >> You get to decide whether positive or negative is the "I'd rather lose"
> >> side. Want to make that configurable as well? Right.
> >
> > Nope, 0 is used as a threshold value in Pacemaker all over the place.
> > So allowing both positive and negative priorities and making 0 the
> > default sounds perfectly sane to me.
> >
> >> I don't think this can be made part of the cib configuration,
> >> DC election takes place before cibs are resynced, so if you have
> >> diverging cibs, you possibly end up with a never ending election?
> >>
> >> Then maybe the election is stable enough,
> >> even after this change to the algorithm.
> >
> > Andrew?
> 
> This whole thread makes me want to hurt kittens.

Yep...

Sorry for that :(

	Lars