[Linux-ha-dev] A curious question about the Order constr aint

[Andrew Beekhof]

On 8/13/06, fancitron <fancitron at 163.com> wrote:
> Hi, all. I'm just starting to explore the rich features of Heartbeat 2.0.x.
> I read from the changelog in heartbeat.spec that (wish I interpret it
> correctly): if there exists an Order constraint such that resource R1
> "before" resource R2 (action is implied to be "start", according to the cib
> dtd), then, if I try to stop R1 while R1 and R2 are both running, R2 will be
> automatically stopped before R1 is stopped, although its target_role is
> still "started". Did I interpret it correctly?

Thats how its supposed to work IIRC

> If the above is true, is it also true that, when I try to start R2 when R1
> and R2 are both NOT running, R1 shall be automatically started before R2 is
> started?

Right again.
And if R1 cant be started, R2 wont be either.

>
> Finally the curious question is, if I define an Order constraint that R1
> start before R1, how will pengine handle it when I try to start/stop R1? Aha
> this question is really non-realistic, but just for theoretical
> completeness, I mean ;-)

Again IIRC, R1 would not get started.  Please dont do this :-)

> A possible generalization might be R1 before R2, R2
> before R1...

Right, thats a logic loop.  "Dont do that."