[ClusterLabs] Antw: [EXT] Any Pacemaker users need negative utilization values?

[Ulrich Windl]

Hi!

I don't use that feature, but couldn't some primitive _add_ to some node's
capacity by running it on that node? Then the number would be negative.
The situation where a nodes capacity could be negative could depend on some
future placement strategy also.

Despite of that, I'd like to see a name change in some future version:
Both, node and resource use "utilization" for two different concepts. I'd like
to see "utilization" for nodes become "provides", while "utilization on
resources will become "requires".

The other thing is: utilization is (AFAIR) an integer; wouldn't it be more
flexible if it were a real/rational/floating-point number? For example: YOu
want to express the node's capacity in GB, but some resource needs less than 1
GB (yes, even today such software exists ;-)) At the moment you'll have to
"scale up" like to MBs or multiplkes of such...

Regards,
Ulrich

>>> Ken Gaillot <kgaillot at redhat.com> schrieb am 19.03.2021 um 22:14 in
Nachricht
<bc21aa9162890d19519d7ae1d7e294bea54fbdd3.camel at redhat.com>:
> Hi,
> 
> While updating some code, I noticed that Pacemaker currently allows
> negative values for resource and node utilization values.
> 
> For those unfamiliar with utilization, it's a way to balance resources
> by node capacity:
> 
>
https://clusterlabs.org/pacemaker/doc/en‑US/Pacemaker/2.0/html‑single/Pacemake

> r_Explained/index.html#idm46061210829040
> 
> Logically, capacities can't be negative, but that doesn't mean someone
> somewhere isn't using them for something ...
> 
> Would anyone object to Pacemaker restricting utilization values to be
> non‑negative? Any negative (or otherwise invalid) values configured
> would be treated as 0.
> ‑‑ 
> Ken Gaillot <kgaillot at redhat.com>
> 
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