x/gantt
Code Issues Proposed changes

Removed scheduler doc costs section

Browse Source 
Since commit 820f43fc (Change-Id
Ie3e7611347c334c359dea98d759345b97c66c9c1)
costs are no longer used, so all references to them have been removed.

Change-Id: I6e02bc47643be9f9dfe9d2e42b2335626bf039e7
This commit is contained in:
Alvaro Lopez Garcia
2013-07-31 09:36:46 +02:00
parent f0f4d050a1
commit 047697c912
1 changed files with 6 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
doc/source/devref/filter_scheduler.rst
View File

@@ -12,11 +12,11 @@ Filtering
During its work Filter Scheduler firstly makes dictionary of unfiltered hosts, During its work Filter Scheduler firstly makes dictionary of unfiltered hosts,
then filters them using filter properties and finally chooses hosts for the then filters them using filter properties and finally chooses hosts for the
requested number of instances (each time it chooses the least costed host and requested number of instances (each time it chooses the most weighed host and
appends it to the list of selected costs). appends it to the list of selected hosts).
If it turns up, that it can't find candidates for the next instance, it means If it turns up, that it can't find candidates for the next instance, it means
that there are no more appropriate instances locally. that there are no more appropriate hosts where the instance could be scheduled.
If we speak about `filtering` and `weighting`, their work is quite flexible If we speak about `filtering` and `weighting`, their work is quite flexible
in the Filter Scheduler. There are a lot of filtering strategies for the in the Filter Scheduler. There are a lot of filtering strategies for the
@@ -259,19 +259,10 @@ driver. The standard nova filters and MyFilter are available to the
FilterScheduler. The RamFilter, ComputeFilter, and MyFilter are used by FilterScheduler. The RamFilter, ComputeFilter, and MyFilter are used by
default when no filters are specified in the request. default when no filters are specified in the request.
Costs and weights Weights
----------------- -------
Filter Scheduler uses so-called **weights** and **costs** during its work. Filter Scheduler uses so-called **weights** during its work.
`Costs` are the computed integers, expressing hosts measure of fitness to be
chosen as a result of the request. Of course, costs are computed due to hosts
characteristics compared with characteristics from the request. So trying to
put instance on a not appropriate host (for example, trying to put really
simple and plain instance on a high performance host) would have high cost, and
putting instance on an appropriate host would have low.
So let's find out, how does all this computing work happen.
The Filter Scheduler weights hosts based on the config option The Filter Scheduler weights hosts based on the config option
``scheduler_weight_classes``, this defaults to ``scheduler_weight_classes``, this defaults to