Synnefo » snf-ganeti

    , oMinResources

-- | The tag-prefix indicating that hsqueeze should consider a node

-- as being standby.

standbyPrefix :: String

standbyPrefix = "htools:standby:"

-- | Predicate of having a standby tag.

hasStandbyTag :: Node.Node -> Bool

hasStandbyTag = any (standbyPrefix `isPrefixOf`) . Node.nTags

-- | In a configuration, mark a node as online or offline.

onlineOfflineNode :: Bool -> (Node.List, Instance.List) -> Ndx ->

                     (Node.List, Instance.List)

onlineOfflineNode offline (nl, il) ndx =

      nd' = Node.setOffline nd offline

-- | Offline or online a list nodes, and return the state after a balancing

-- attempt.

onlineOfflineNodes :: Bool -> [Ndx] -> (Node.List, Instance.List)

                      -> (Node.List, Instance.List)

onlineOfflineNodes offline ndxs conf =

  let conf' = foldl (onlineOfflineNode offline) conf ndxs

-- | Offline a list of nodes, and return the state after balancing.

offlineNodes :: [Ndx] -> (Node.List, Instance.List)

                -> (Node.List, Instance.List)

offlineNodes = onlineOfflineNodes True

-- | Online a list of nodes, and return the state after balancing.

onlineNodes :: [Ndx] -> (Node.List, Instance.List)

               -> (Node.List, Instance.List)

onlineNodes = onlineOfflineNodes False

-- | Predicate on whether a list of nodes can be offlined or onlined

-- simultaneously in a given configuration, while still leaving enough

-- capacity on every node for the given instance.

canOnlineOffline :: Bool -> Instance.Instance -> (Node.List, Instance.List)

                    -> [Node.Node] ->Bool

canOnlineOffline offline inst conf nds = 

  let conf' = onlineOfflineNodes offline (map Node.idx nds) conf

-- | Predicate on whether a list of nodes can be offlined simultaneously.

canOffline :: Instance.Instance -> (Node.List, Instance.List) ->

              [Node.Node] -> Bool

canOffline = canOnlineOffline True

-- | Predicate on whether onlining a list of nodes suffices to get enough

-- free resources for given instance.

sufficesOnline :: Instance.Instance -> (Node.List, Instance.List)

                  -> [Node.Node] ->  Bool

sufficesOnline = canOnlineOffline False

  in if canOffline inst conf (nd:nds') then nd:nds' else nds'

-- | Try to provide enough resources by onlining an initial segment of

-- a list of nodes. Return Nothing, if even onlining all of them is not

-- enough.

tryOnline :: Instance.Instance -> (Node.List, Instance.List) -> [Node.Node]

             -> Maybe [Node.Node]

tryOnline inst conf = listToMaybe . filter (sufficesOnline inst conf) . inits

      minf = optMinResources opts

  let nodelist = IntMap.elems nlf

      offlineCandidates = 

        $ nodelist

      onlineCandidates =

        filter (liftA2 (&&) Node.offline hasStandbyTag) nodelist

      minInstance = instanceFromSpecAndFactor "targetInstance" minf std

      (fin_off_nl, fin_off_il) = offlineNodes (map Node.idx toOffline) conf

      final_off_cdata =

        ini_cdata { cdNodes = fin_off_nl, cdInstances = fin_off_il }

      toOnline = tryOnline minInstance conf onlineCandidates

      nodesToOnline = fromMaybe onlineCandidates toOnline

      (fin_on_nl, fin_on_il) = onlineNodes (map Node.idx nodesToOnline) conf

      final_on_cdata =

        ini_cdata { cdNodes = fin_on_nl, cdInstances = fin_on_il }

  when (verbose > 1) . putStrLn

    $ "Online candidates: " ++ commaJoin (map Node.name onlineCandidates)

  if not (allNodesCapacityFor minInstance conf)

    then do

      unless (optNoHeaders opts) $

        putStrLn "'Nodes to online'"

      mapM_ (putStrLn . Node.name) nodesToOnline

      when (verbose > 1 && isNothing toOnline) . putStrLn $

        "Onlining all nodes will not yield enough capacity"

      maybeSaveData (optSaveCluster opts)

         "squeezed" "after hsqueeze expansion" final_on_cdata

    else

      if null toOffline

        then do      

          unless (optNoHeaders opts) $

            putStrLn "'No action'"

          maybeSaveData (optSaveCluster opts)

            "squeezed" "after hsqueeze doing nothing" ini_cdata

        else do

          unless (optNoHeaders opts) $

            putStrLn "'Nodes to offline'"

          mapM_ (putStrLn . Node.name) toOffline

          maybeSaveData (optSaveCluster opts)

            "squeezed" "after hsqueeze run" final_off_cdata