[Pacemaker] Resource capacity limit

[Andrew Beekhof]

On Fri, Nov 6, 2009 at 8:27 AM, Yan Gao <ygao at novell.com> wrote:
> Hi Andrew,
>
> Andrew Beekhof wrote:

>> Whats the behavior if a node has either no utilization block or no
>> value for that attribute?
> If so, it would be regarded that the node has no any capacity or no that
> specific capacity.
>
>> Can a resource with a utilization block still be placed there?
> No, unless the utilization block is blank. As long as any attribute is set
> in resource utilization, which means the resource requests some kind of
> capacity, while a node has no that capacity, the node would not be considered.
>
> A interesting case is, if a resource has no utilization block, it would be regarded
> that the resource doesn't consume any capacity. so it could be placed on any node,
> even the node has no utilization block (no any capacity).
>
> Do you think the behavior is reasonable?

I think so.

I've been thinking about this more and while this will work, I think
we can make it better.

I'd like to see the while-block from native_color() be a function that
is called from native_assign_node().
And instead of a limit-utilization option, we'd have
placement-strategy=(default|utilization|minimal)

Default ::= what we do now
Utilization ::= what you've implemented
Minimal ::= what you've implemented _without_ the load balancing we
currently do.

(Maybe the names could be improved, but hopefully you get the idea).

The last one is interesting because it allows us to concentrate
services on the minimum number of required nodes (and potentially
power some of the others down).