Synnefo » snf-ganeti

-- | Check that multiple instances can allocated correctly, without

-- rebalances needed.

prop_IterateAlloc_sane :: Instance.Instance -> Property

prop_IterateAlloc_sane inst =

  forAll (choose (5, 10)) $ \count ->

  forAll genOnlineNode $ \node ->

  forAll (choose (2, 5)) $ \limit ->

  let (nl, il, inst') = makeSmallEmptyCluster node count inst

      reqnodes = Instance.requiredNodes $ Instance.diskTemplate inst

      allocnodes = Cluster.genAllocNodes defGroupList nl reqnodes True

  in case allocnodes >>= \allocnodes' ->

     Cluster.iterateAlloc nl il (Just limit) inst' allocnodes' [] [] of

       Bad msg -> failTest msg

       Ok (_, xnl, xil, _, _) ->

         let old_score = Cluster.compCV xnl

             tbl = Cluster.Table xnl xil old_score []

         in case Cluster.tryBalance tbl True True False 0 1e-4 of

              Nothing -> passTest

              Just (Cluster.Table ynl _ new_score plcs) ->

                -- note that with a "min_gain" of zero, sometime

                -- rounding errors can trigger a rebalance that

                -- improves the score by e.g. 2e-14; in order to

                -- prevent such no-real-change moves from happening,

                -- we check for a min-gain of 1e-9

                -- FIXME: correct rebalancing to not do no-ops

                printTestCase

                  ("Cluster can be balanced after allocation\n" ++

                   " old cluster (score " ++ show old_score ++

                   "):\n" ++ Cluster.printNodes xnl [] ++

                   " new cluster (score " ++ show new_score ++

                   "):\n" ++ Cluster.printNodes ynl [] ++

                   "placements:\n" ++ show plcs ++ "\nscore delta: " ++

                   show (old_score - new_score))

                  (old_score - new_score < 1e-9)