Open Stack

On 10/09/2015 11:09 AM, Zane Bitter wrote:

> The optimal way to do this would be a weighted random selection, where the
> probability of any given host being selected is proportional to its weighting.
> (Obviously this is limited by the accuracy of the weighting function in
> expressing your actual preferences - and it's at least conceivable that this
> could vary with the number of schedulers running.)
>
> In fact, the choice of the name 'weighting' would normally imply that it's done
> this way; hearing that the 'weighting' is actually used as a 'score' with the
> highest one always winning is quite surprising.

If you've only got one scheduler, there's no need to get fancy, you just pick 
the "best" host based on your weighing function.

It's only when you've got parallel schedulers that things get tricky.

Chris