content: {-| Cluster rebalancer.
  
  -}
  
  {-
  
  Copyright (C) 2009, 2010, 2011, 2012, 2013 Google Inc.
  All rights reserved.
  
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are
  met:
  
  1. Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer.
  
  2. Redistributions in binary form must reproduce the above copyright
  notice, this list of conditions and the following disclaimer in the
  documentation and/or other materials provided with the distribution.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  -}
  
  module Ganeti.HTools.Program.Hbal
    ( main
    , options
    , arguments
    , iterateDepth
    ) where
  
  import Control.Arrow ((&&&))
  import Control.Lens (over)
  import Control.Monad
  import Data.List
  import Data.Maybe (isNothing, fromMaybe)
  import System.Exit
  import System.IO
  
  import Text.Printf (printf)
  
  import Ganeti.HTools.AlgorithmParams (AlgorithmOptions(..), fromCLIOptions)
  import qualified Ganeti.HTools.Container as Container
  import qualified Ganeti.HTools.Cluster as Cluster
  import qualified Ganeti.HTools.Cluster.Metrics as Metrics
  import qualified Ganeti.HTools.Cluster.Utils as ClusterUtils
  import qualified Ganeti.HTools.Group as Group
  import qualified Ganeti.HTools.Node as Node
  import qualified Ganeti.HTools.Instance as Instance
  
  import Ganeti.BasicTypes
  import Ganeti.Common
  import Ganeti.HTools.CLI
  import Ganeti.HTools.ExtLoader
  import Ganeti.HTools.Types
  import Ganeti.HTools.Loader
  import Ganeti.OpCodes (wrapOpCode, setOpComment, setOpPriority)
  import Ganeti.OpCodes.Lens (metaParamsL, opReasonL)
  import Ganeti.JQueue (currentTimestamp, reasonTrailTimestamp)
  import Ganeti.JQueue.Objects (Timestamp)
  import Ganeti.Jobs as Jobs
  import Ganeti.Utils
  
  import Ganeti.Version (version)
  
  -- | Options list and functions.
  options :: IO [OptType]
  options = do
    luxi <- oLuxiSocket
    return
      [ oPrintNodes
      , oPrintInsts
      , oPrintCommands
      , oDataFile
      , oEvacMode
      , oRestrictedMigrate
      , oRapiMaster
      , luxi
      , oIAllocSrc
      , oExecJobs
      , oFirstJobGroup
      , oReason
      , oGroup
      , oMaxSolLength
      , oVerbose
      , oQuiet
      , oOfflineNode
      , oStaticKvmNodeMemory
      , oMinScore
      , oMaxCpu
      , oMinDisk
      , oMinGain
      , oMinGainLim
      , oDiskMoves
      , oSelInst
      , oInstMoves
      , oIgnoreSoftErrors
      , oDynuFile
      , oIgnoreDyn 
      , oMonD
      , oMonDDataFile
      , oMonDExitMissing
      , oMonDXen
      , oExTags
      , oExInst
      , oSaveCluster
      , oPriority
      ]
  
  -- | The list of arguments supported by the program.
  arguments :: [ArgCompletion]
  arguments = []
  
  -- | Wraps an 'OpCode' in a 'MetaOpCode' while also adding a comment
  -- about what generated the opcode.
  annotateOpCode :: Maybe String -> Timestamp -> Jobs.Annotator
  annotateOpCode reason ts =
    over (metaParamsL . opReasonL)
        (++ [( "hbal", fromMaybe ("hbal " ++ version ++ " called") reason
             , reasonTrailTimestamp ts)])
    . setOpComment ("rebalancing via hbal " ++ version)
    . wrapOpCode
  
  {- | Start computing the solution at the given depth and recurse until
  we find a valid solution or we exceed the maximum depth.
  
  -}
  iterateDepth :: Bool             -- ^ Whether to print moves
               -> AlgorithmOptions -- ^ Algorithmic options to apply
               -> Cluster.Table    -- ^ The starting table
               -> Int              -- ^ Remaining length
               -> Int              -- ^ Max node name len
               -> Int              -- ^ Max instance name len
               -> [MoveJob]        -- ^ Current command list
               -> Score            -- ^ Score at which to stop
               -> IO (Cluster.Table, [MoveJob]) -- ^ The resulting table
                                                -- and commands
  iterateDepth printmove algOpts ini_tbl max_rounds nmlen imlen cmd_strs
               min_score =
    let Cluster.Table ini_nl ini_il _ _ = ini_tbl
        allowed_next = Cluster.doNextBalance ini_tbl max_rounds min_score
        m_fin_tbl = if allowed_next
                      then Cluster.tryBalance algOpts ini_tbl
                      else Nothing
    in case m_fin_tbl of
         Just fin_tbl ->
           do
             let (Cluster.Table _ _ _ fin_plc) = fin_tbl
             cur_plc@(idx, _, _, move, _) <-
               exitIfEmpty "Empty placement list returned for solution?!" fin_plc
             let fin_plc_len = length fin_plc
                 (sol_line, cmds) = Cluster.printSolutionLine ini_nl ini_il
                                    nmlen imlen cur_plc fin_plc_len
                 afn = Cluster.involvedNodes ini_il cur_plc
                 upd_cmd_strs = (afn, idx, move, cmds):cmd_strs
             when printmove $ do
                 putStrLn sol_line
                 hFlush stdout
             iterateDepth printmove algOpts fin_tbl max_rounds
                          nmlen imlen upd_cmd_strs min_score
         Nothing -> return (ini_tbl, cmd_strs)
  
  -- | Displays the cluster stats.
  printStats :: Node.List -> Node.List -> IO ()
  printStats ini_nl fin_nl = do
    let ini_cs = Cluster.totalResources ini_nl
        fin_cs = Cluster.totalResources fin_nl
    printf "Original: mem=%d disk=%d\n"
               (Cluster.csFmem ini_cs) (Cluster.csFdsk ini_cs) :: IO ()
    printf "Final:    mem=%d disk=%d\n"
               (Cluster.csFmem fin_cs) (Cluster.csFdsk fin_cs)
  
  -- | Executes the jobs, if possible and desired.
  maybeExecJobs :: Options
                -> [a]
                -> Node.List
                -> Instance.List
                -> [JobSet]
                -> IO (Result ())
  maybeExecJobs opts ord_plc fin_nl il cmd_jobs =
    if optExecJobs opts && not (null ord_plc)
      then (case optLuxi opts of
              Nothing ->
                return $ Bad "Execution of commands possible only on LUXI"
              Just master -> do
                ts <- currentTimestamp
                let annotator = maybe id setOpPriority (optPriority opts) .
                                annotateOpCode (optReason opts) ts
                execWithCancel annotator master $
                  zip (map toOpcodes cmd_jobs) (map toDescr cmd_jobs))
      else return $ Ok ()
    where toOpcodes = map (\(_, idx, move, _) ->
                            Cluster.iMoveToJob fin_nl il idx move)
          toDescr job = "Executing jobset for instances " ++ commaJoin
                         (map (\(_, idx, _, _) -> Container.nameOf il idx) job)
  
  -- | Select the target node group.
  selectGroup :: Options -> Group.List -> Node.List -> Instance.List
              -> IO (String, (Node.List, Instance.List))
  selectGroup opts gl nlf ilf = do
    let ngroups = ClusterUtils.splitCluster nlf ilf
    when (length ngroups > 1 && isNothing (optGroup opts)) $ do
      hPutStrLn stderr "Found multiple node groups:"
      mapM_ (hPutStrLn stderr . ("  " ++) . Group.name .
             flip Container.find gl . fst) ngroups
      exitErr "Aborting."
  
    case optGroup opts of
      Nothing -> do
        (gidx, cdata) <- exitIfEmpty "No groups found by splitCluster?!" ngroups
        let grp = Container.find gidx gl
        return (Group.name grp, cdata)
      Just g -> case Container.findByName gl g of
        Nothing -> do
          hPutStrLn stderr $ "Node group " ++ g ++
            " not found. Node group list is:"
          mapM_ (hPutStrLn stderr . ("  " ++) . Group.name ) (Container.elems gl)
          exitErr "Aborting."
        Just grp ->
            case lookup (Group.idx grp) ngroups of
              Nothing ->
                -- This will only happen if there are no nodes assigned
                -- to this group
                return (Group.name grp, (Container.empty, Container.empty))
              Just cdata -> return (Group.name grp, cdata)
  
  -- | Do a few checks on the cluster data.
  checkCluster :: Int -> Node.List -> Instance.List -> IO ()
  checkCluster verbose nl il = do
    -- nothing to do on an empty cluster
    when (Container.null il) $ do
           printf "Cluster is empty, exiting.\n"::IO ()
           exitSuccess
  
    -- hbal doesn't currently handle split clusters
    let split_insts = Cluster.findSplitInstances nl il
    unless (null split_insts || verbose <= 1) $ do
      hPutStrLn stderr "Found instances belonging to multiple node groups:"
      mapM_ (\i -> hPutStrLn stderr $ "  " ++ Instance.name i) split_insts
      hPutStrLn stderr "These instances will not be moved."
  
    printf "Loaded %d nodes, %d instances\n"
               (Container.size nl)
               (Container.size il)::IO ()
  
    let csf = commonSuffix nl il
    when (not (null csf) && verbose > 1) $
         printf "Note: Stripping common suffix of '%s' from names\n" csf
  
  -- | Do a few checks on the selected group data.
  checkGroup :: Bool -> Int -> String -> Node.List -> Instance.List -> IO ()
  checkGroup force verbose gname nl il = do
    printf "Group size %d nodes, %d instances\n"
               (Container.size nl)
               (Container.size il)::IO ()
  
    putStrLn $ "Selected node group: " ++ gname
  
    let (bad_nodes, bad_instances) = Cluster.computeBadItems nl il
    unless (verbose < 1) $ printf
               "Initial check done: %d bad nodes, %d bad instances.\n"
               (length bad_nodes) (length bad_instances)
  
    let other_nodes = filter (not . (`elem` bad_nodes)) $ Container.elems nl
        node_status = map (Node.name &&& Node.getPolicyHealth) other_nodes
        policy_bad = filter (isBad . snd) node_status
  
    when (verbose > 4) $ do
      printf "Bad nodes: %s\n" . show $ map Node.name bad_nodes :: IO ()
      printf "N+1 happy nodes: %s\n" . show $ map Node.name other_nodes :: IO ()
      printf "Node policy status: %s\n" $ show node_status :: IO ()
  
    unless (null bad_nodes) $
           putStrLn "Cluster is not N+1 happy, continuing but no guarantee \
                    \that the cluster will end N+1 happy."
  
    unless (null policy_bad) $ do
      printf "The cluster contains %d policy-violating nodes.\n"
        $ length policy_bad :: IO ()
      putStrLn $ if force
        then "Continuing, ignoring soft errors."
        else "Continuing, but the set of moves might be too restricted;\
             \ consider using the --ignore-soft-errors option."
  
  -- | Check that we actually need to rebalance.
  checkNeedRebalance :: Options -> Score -> Score -> IO ()
  checkNeedRebalance opts ini_cv opt_cv = do
    let min_cv = optMinScore opts
    when (ini_cv - opt_cv < min_cv) $ do
           printf "Cluster is already well balanced (initial score %.6g,\n\
                  \optimum score due to N+1 reservations %.6g,\n\
                  \minimum score %.6g).\nNothing to do, exiting\n"
                  ini_cv opt_cv min_cv:: IO ()
           exitSuccess
  
  -- | Main function.
  main :: Options -> [String] -> IO ()
  main opts args = do
    unless (null args) $ exitErr "This program doesn't take any arguments."
  
    let verbose = optVerbose opts
        shownodes = optShowNodes opts
        showinsts = optShowInsts opts
        force = optIgnoreSoftErrors opts
  
    ini_cdata@(ClusterData gl fixed_nl ilf ctags ipol) <- loadExternalData opts
  
    when (verbose > 1) $ do
         putStrLn $ "Loaded cluster tags: " ++ intercalate "," ctags
         putStrLn $ "Loaded cluster ipolicy: " ++ show ipol
  
    nlf <- setNodeStatus opts fixed_nl
    checkCluster verbose nlf ilf
  
    maybeSaveData (optSaveCluster opts) "original" "before balancing" ini_cdata
  
    (gname, (nl, il)) <- selectGroup opts gl nlf ilf
  
    checkGroup force verbose gname nl il
  
    maybePrintInsts showinsts "Initial" (Cluster.printInsts nl il)
  
    maybePrintNodes shownodes "Initial cluster" (Cluster.printNodes nl)
  
    let ini_cv = Metrics.compCV nl
        opt_cv = Metrics.optimalCVScore nl
        ini_tbl = Cluster.Table nl il ini_cv []
        min_cv = optMinScore opts
  
    if verbose > 2
      then printf "Initial coefficients: overall %.8f\n%s"
             ini_cv (Metrics.printStats "  " nl)::IO ()
      else printf "Initial score: %.8f\n" ini_cv
  
    checkNeedRebalance opts ini_cv opt_cv
  
    putStrLn "Trying to minimize the CV..."
    let imlen = maximum . map (length . Instance.alias) $ Container.elems il
        nmlen = maximum . map (length . Node.alias) $ Container.elems nl
  
    (fin_tbl, cmd_strs) <- iterateDepth True (fromCLIOptions opts) ini_tbl
                           (optMaxLength opts)
                           nmlen imlen [] (opt_cv + min_cv)
    let (Cluster.Table fin_nl fin_il fin_cv fin_plc) = fin_tbl
        ord_plc = reverse fin_plc
        sol_msg = case () of
                    _ | null fin_plc -> printf "No solution found\n"
                      | verbose > 2 ->
                          printf "Final coefficients:   overall %.8f\n%s"
                          fin_cv (Metrics.printStats "  " fin_nl)
                      | otherwise ->
                          printf "Cluster score improved from %.8f to %.8f\n"
                          ini_cv fin_cv ::String
  
    putStr sol_msg
  
    unless (verbose < 1) $
           printf "Solution length=%d\n" (length ord_plc)
  
    let cmd_jobs = (if optFirstJobGroup opts then take 1 else id)
                   $ Cluster.splitJobs cmd_strs
  
    maybeSaveCommands (if optFirstJobGroup opts
                          then "First set of jobs:"
                          else "Commands to run to reach the above solution:")
                      opts
      $ Cluster.formatCmds cmd_jobs
  
    maybeSaveData (optSaveCluster opts) "balanced" "after balancing"
                  ini_cdata { cdNodes = fin_nl, cdInstances = fin_il }
  
    maybePrintInsts showinsts "Final" (Cluster.printInsts fin_nl fin_il)
  
    maybePrintNodes shownodes "Final cluster" (Cluster.printNodes fin_nl)
  
    when (verbose > 3) $ printStats nl fin_nl
  
    exitIfBad "hbal" =<< maybeExecJobs opts ord_plc fin_nl il cmd_jobs
  