Restrict move list based on offline node status

[ganeti-local] / Ganeti / HTools / Cluster.hs

diff --git a/Ganeti/HTools/Cluster.hs b/Ganeti/HTools/Cluster.hs
index c7b7350..72ab0ff 100644 (file)
--- a/Ganeti/HTools/Cluster.hs
+++ b/Ganeti/HTools/Cluster.hs
@@ -1,7 +1,7 @@
 {-| Implementation of cluster-wide logic.
 
 This module holds all pure cluster-logic; I\/O related functionality
-goes into the "Main" module.
+goes into the "Main" module for the individual binaries.
 
 -}
 
@@ -45,6 +45,7 @@ import Ganeti.HTools.Utils
 
 type NodeList = Container.Container Node.Node
 type InstanceList = Container.Container Instance.Instance
+-- | A separate name for the cluster score type
 type Score = Double
 
 -- | The description of an instance placement.
@@ -430,6 +431,21 @@ checkSingleStep ini_tbl target cur_tbl move =
           in
             compareTables cur_tbl upd_tbl
 
+-- | Given the status of the current secondary as a valid new node
+-- and the current candidate target node,
+-- generate the possible moves for a instance.
+possibleMoves :: Bool -> Int -> [IMove]
+possibleMoves True tdx =
+    [ReplaceSecondary tdx,
+     ReplaceAndFailover tdx,
+     ReplacePrimary tdx,
+     FailoverAndReplace tdx]
+
+possibleMoves False tdx =
+    [ReplaceSecondary tdx,
+     ReplaceAndFailover tdx]
+
+-- | Compute the best move for a given instance.
 checkInstanceMove :: [Int]             -- Allowed target node indices
                   -> Table             -- Original table
                   -> Instance.Instance -- Instance to move
@@ -439,11 +455,11 @@ checkInstanceMove nodes_idx ini_tbl target =
         opdx = Instance.pnode target
         osdx = Instance.snode target
         nodes = filter (\idx -> idx /= opdx && idx /= osdx) nodes_idx
-        aft_failover = checkSingleStep ini_tbl target ini_tbl Failover
-        all_moves = concatMap (\idx -> [ReplacePrimary idx,
-                                        ReplaceSecondary idx,
-                                        ReplaceAndFailover idx,
-                                        FailoverAndReplace idx]) nodes
+        use_secondary = elem osdx nodes_idx
+        aft_failover = if use_secondary -- if allowed to failover
+                       then checkSingleStep ini_tbl target ini_tbl Failover
+                       else ini_tbl
+        all_moves = concatMap (possibleMoves use_secondary) nodes
     in
       -- iterate over the possible nodes for this instance
       foldl' (checkSingleStep ini_tbl target) aft_failover all_moves