On Tue, Mar 17, 2015 at 06:29:56PM +0100, 'Klaus Aehlig' via ganeti-devel wrote:
With the addition of the total relative reserved memory, the optimal
cluster score no longer is 0 but the fraction of a machine that in
total is unused to keep N+1 redundancy. Add a function computing this
optimal value.
Signed-off-by: Klaus Aehlig <[email protected]>
---
src/Ganeti/HTools/Cluster.hs | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/src/Ganeti/HTools/Cluster.hs b/src/Ganeti/HTools/Cluster.hs
index b62a426..73a0978 100644
--- a/src/Ganeti/HTools/Cluster.hs
+++ b/src/Ganeti/HTools/Cluster.hs
@@ -76,6 +76,7 @@ module Ganeti.HTools.Cluster
, doNextBalance
, tryBalance
, compCV
+ , optimalCVScore
, compCVNodes
, compDetailedCV
, printStats
@@ -117,6 +118,7 @@ import qualified Ganeti.HTools.Container as Container
import qualified Ganeti.HTools.Instance as Instance
import qualified Ganeti.HTools.Nic as Nic
import qualified Ganeti.HTools.Node as Node
+import qualified Ganeti.HTools.PeerMap as P
import qualified Ganeti.HTools.Group as Group
import Ganeti.HTools.Types
import Ganeti.Compat
@@ -357,6 +359,12 @@ computeAllocationDelta cini cfin =
}
in (rini, rfin, runa)
+-- | Coefficient for the total reserved memory in the cluster metric. We
+-- use a (local) constant here, as it is also used in the computation of
+-- the best possible cluster score.
+reservedMemRtotalCoeff :: Double
+reservedMemRtotalCoeff = 0.25
+
-- | The names and weights of the individual elements in the CV list, together
-- with their statistical accumulation function and a bit to decide whether it
-- is a statistics for online nodes.
@@ -382,9 +390,27 @@ detailedCVInfoExt = [ ((0.5, "free_mem_cv"),
(getStdDevStatistics, True))
, (getStdDevStatistics, True))
, ((0.5, "spindles_cv_forth"), (getStdDevStatistics, True))
, ((1, "location_score"), (getSumStatistics, True))
- , ((0.25, "reserved_mem_rtotal"), (getSumStatistics,
True))
+ , ( (reservedMemRtotalCoeff, "reserved_mem_rtotal")
+ , (getSumStatistics, True))
]
+-- | Compute the lower bound of the cluster score, i.e., the sum of the minimal
+-- values for all cluster score values that are not 0 on a perfectly balanced
+-- cluster.
+optimalCVScore :: Node.List -> Double
+optimalCVScore nodelist = fromMaybe 0 $ do
+ let nodes = Container.elems nodelist
+ unless (length nodes > 1) Nothing
+ let nodeMems = map Node.tMem nodes
+ totalMem = sum nodeMems
+ totalMemOneLessNode = totalMem - maximum nodeMems
+ unless (totalMemOneLessNode > 0) Nothing
+ let totalDrbdMem = fromIntegral . sum $ map (P.sumElems . Node.peers) nodes
+ optimalUsage = totalDrbdMem / totalMem
+ optimalUsageOneLessNode = totalDrbdMem / totalMemOneLessNode
+ relativeReserved = optimalUsageOneLessNode - optimalUsage
+ return $ reservedMemRtotalCoeff * relativeReserved
Just nitpicking:
unless p Nothing
can be replaced by
guard p
+
-- | The names and weights of the individual elements in the CV list.
detailedCVInfo :: [(Double, String)]
detailedCVInfo = map fst detailedCVInfoExt
--
2.2.0.rc0.207.ga3a616c
In any case LGTM
