On Mon, Dec 01, 2014 at 02:52:43PM +0100, 'Aaron Karper' via ganeti-devel wrote:
> Specifically it gives a better high-level overview of what is happening
> and what functions are the core.
>
> Signed-off-by: Aaron Karper <[email protected]>
> ---
> src/Ganeti/HTools/Cluster.hs | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/src/Ganeti/HTools/Cluster.hs b/src/Ganeti/HTools/Cluster.hs
> index 368c43f..310400a 100644
> --- a/src/Ganeti/HTools/Cluster.hs
> +++ b/src/Ganeti/HTools/Cluster.hs
> @@ -3,6 +3,12 @@
> This module holds all pure cluster-logic; I\/O related functionality
> goes into the /Main/ module for the individual binaries.
>
> +The purpose is to minimize the Score of a cluster, which is a measure of the
> +imbalance of the nodes (see 'compDetailedCV' and 'compClusterStatistics').
> The
> +optimization searches the space of possible moves and requires each move to
> +improve the score. Since the function optimized is convex, we use
Which notion of convex are you using? Or, more precisely, over which domain are
you considering convexnes? We're trying to find an optimal assignment from
instances
to (pairs of) nodes which is a discrete set of mappings where I don't see an
obvious
vector space structure over the rationals.
Note that you cannot take the space of node resources as a high-dimensional
vector
space over the reals, as the cluster metrics has various counting aspects to it
(like "number of N+1 violations") that are not a function of the free and used
resources (as it also depends on peer-relation induced by the instances.
> +hill-climbing (downhill). This doesn't necessarily give the optimal solution,
> +but it is reasonably good.
> -}
>
> {-
> --
> 2.2.0.rc0.207.ga3a616c
>
--
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