[Pacemaker] Resource capacity limit

[Andrew Beekhof]

On Fri, Nov 13, 2009 at 8:23 AM, Yan Gao <ygao at novell.com> wrote:
> Hi Andrew, Lars,
>
> Andrew Beekhof wrote:
>> I'd like to see the while-block from native_color() be a function that
>> is called from native_assign_node().
> It seems to be too late to filter out the nodes without enough capacity from
> native_assign_node(). I wrote a have_enough_capacity() function which is
> called from native_choose_node() to achieve that.

Ah, yes, thats what I meant.
Well done interpreting my vague design :-)

>
>> And instead of a limit-utilization option, we'd have
>> placement-strategy=(default|utilization|minimal)
> Done. And added a "balanced" option as Lars advised.
>
>>
>> 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).
> Done.
>
> Minimal:
> Consider the utilization of nodes and resources. While if a resource has
> the same score for several available nodes, do _not_ balance the load.
> That implies that the resources  will be concentrated to minimal number of nodes.
>
> Balanced:
> Consider the utilization of nodes and resources. If a resource has
> the same score for several available nodes:
> * First, balance the load according to the remaining capacity of nodes.
> (implemented from compare_capacity())
> * If the nodes still have the equal remaining capacity, then balance
> the load according to the numbers of resources that the nodes will run.
>
> The strategies are determined mainly from sort_node_weight(), so I changed the
> prototypes of some functions a bit.
>
> Please help to review and test it. Any comments and suggestions are welcome:-)

Will do.  Thanks!