[Pacemaker] Resource capacity limit

[Lars Marowsky-Bree]

On 2009-11-06T12:45:17, Andrew Beekhof <andrew at beekhof.net> wrote:

> 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

These two are obvious, since we can already do them with existing code.

The following:

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

(Basically, concentrate load on as few nodes as possible. Rucksack
problem.)

To this I'd like to add 

Balanced ::= try to spread the load as evenly as possible. This is hard
to define - perhaps "maximise average free resources on nodes".

These latter two are harder, and basically require a linear optimization
engine to be integrated. But I'd, of course, love to see them. 

(Automatically powering down nodes is not that trivial, since we'd need
some way to wake them up in-time; STONITH actually can do that, but it
needs some thinking to get right. At least though those nodes could go
to power savings mode, so it'd definitely help.)

With those, Pacemaker would be a full-scale replacement for certain data
center management and automation frameworks ;-)


Regards,
    Lars

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