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{-| Cluster rebalancer.

-}

{-

Copyright (C) 2009, 2010, 2011 Google Inc.

This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful, but

WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

02110-1301, USA.

-}

module Ganeti.HTools.Program.Hbal (main) where

import Control.Concurrent (threadDelay)

import Control.Exception (bracket)

import Control.Monad

import Data.List

import Data.Maybe (isJust, isNothing, fromJust)

import Data.IORef

import System (exitWith, ExitCode(..))

import System.IO

import System.Posix.Process

import System.Posix.Signals

import qualified System

import Text.Printf (printf, hPrintf)

import qualified Ganeti.HTools.Container as Container

import qualified Ganeti.HTools.Cluster as Cluster

import qualified Ganeti.HTools.Group as Group

import qualified Ganeti.HTools.Node as Node

import qualified Ganeti.HTools.Instance as Instance

import Ganeti.HTools.CLI

import Ganeti.HTools.ExtLoader

import Ganeti.HTools.Utils

import Ganeti.HTools.Types

import Ganeti.HTools.Loader

import qualified Ganeti.Luxi as L

import Ganeti.Jobs

-- | Options list and functions.

options :: [OptType]

options =

    [ oPrintNodes

    , oPrintInsts

    , oPrintCommands

    , oOneline

    , oDataFile

    , oEvacMode

    , oRapiMaster

    , oLuxiSocket

    , oExecJobs

    , oGroup

    , oMaxSolLength

    , oVerbose

    , oQuiet

    , oOfflineNode

    , oMinScore

    , oMaxCpu

    , oMinDisk

    , oMinGain

    , oMinGainLim

    , oDiskMoves

    , oSelInst

    , oInstMoves

    , oDynuFile

    , oExTags

    , oExInst

    , oSaveCluster

    , oShowVer

    , oShowHelp

    ]

{- | Start computing the solution at the given depth and recurse until

we find a valid solution or we exceed the maximum depth.

-}

iterateDepth :: Cluster.Table    -- ^ The starting table

             -> Int              -- ^ Remaining length

             -> Bool             -- ^ Allow disk moves

             -> Bool             -- ^ Allow instance moves

             -> Int              -- ^ Max node name len

             -> Int              -- ^ Max instance name len

             -> [MoveJob]        -- ^ Current command list

             -> Bool             -- ^ Whether to be silent

             -> Score            -- ^ Score at which to stop

             -> Score            -- ^ Min gain limit

             -> Score            -- ^ Min score gain

             -> Bool             -- ^ Enable evacuation mode

             -> IO (Cluster.Table, [MoveJob]) -- ^ The resulting table

                                              -- and commands

iterateDepth ini_tbl max_rounds disk_moves inst_moves nmlen imlen

             cmd_strs oneline min_score mg_limit min_gain evac_mode =

    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 ini_tbl disk_moves inst_moves

                         evac_mode mg_limit min_gain

                    else Nothing

    in

      case m_fin_tbl of

        Just fin_tbl ->

            do

              let

                  (Cluster.Table _ _ _ fin_plc) = fin_tbl

                  fin_plc_len = length fin_plc

                  cur_plc@(idx, _, _, move, _) = head 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

              unless oneline $ do

                       putStrLn sol_line

                       hFlush stdout

              iterateDepth fin_tbl max_rounds disk_moves inst_moves

                           nmlen imlen upd_cmd_strs oneline min_score

                           mg_limit min_gain evac_mode

        Nothing -> return (ini_tbl, cmd_strs)

-- | Formats the solution for the oneline display.

formatOneline :: Double -> Int -> Double -> String

formatOneline ini_cv plc_len fin_cv =

    printf "%.8f %d %.8f %8.3f" ini_cv plc_len fin_cv

               (if fin_cv == 0 then 1 else ini_cv / fin_cv)

-- | Polls a set of jobs at a fixed interval until all are finished

-- one way or another.

waitForJobs :: L.Client -> [String] -> IO (Result [JobStatus])

waitForJobs client jids = do

  sts <- L.queryJobsStatus client jids

  case sts of

    Bad x -> return $ Bad x

    Ok s -> if any (<= JOB_STATUS_RUNNING) s

            then do

              -- TODO: replace hardcoded value with a better thing

              threadDelay (1000000 * 15)

              waitForJobs client jids

            else return $ Ok s

-- | Check that a set of job statuses is all success.

checkJobsStatus :: [JobStatus] -> Bool

checkJobsStatus = all (== JOB_STATUS_SUCCESS)

-- | Wrapper over execJobSet checking for early termination.

execWrapper :: String -> Node.List

           -> Instance.List -> IORef Int -> [JobSet] -> IO Bool

execWrapper _      _  _  _    [] = return True

execWrapper master nl il cref alljss = do

  cancel <- readIORef cref

  (if cancel > 0

   then do

     hPrintf stderr "Exiting early due to user request, %d\

                    \ jobset(s) remaining." (length alljss)::IO ()

     return False

   else execJobSet master nl il cref alljss)

-- | Execute an entire jobset.

execJobSet :: String -> Node.List

           -> Instance.List -> IORef Int -> [JobSet] -> IO Bool

execJobSet _      _  _  _    [] = return True

execJobSet master nl il cref (js:jss) = do

  -- map from jobset (htools list of positions) to [[opcodes]]

  let jobs = map (\(_, idx, move, _) ->

                      Cluster.iMoveToJob nl il idx move) js

  let descr = map (\(_, idx, _, _) -> Container.nameOf il idx) js

  putStrLn $ "Executing jobset for instances " ++ commaJoin descr

  jrs <- bracket (L.getClient master) L.closeClient

         (\client -> do

            jids <- L.submitManyJobs client jobs

            case jids of

              Bad x -> return $ Bad x

              Ok x -> do

                putStrLn $ "Got job IDs " ++ commaJoin x

                waitForJobs client x

         )

  (case jrs of

     Bad x -> do

       hPutStrLn stderr $ "Cannot compute job status, aborting: " ++ show x

       return False

     Ok x -> if checkJobsStatus x

             then execWrapper master nl il cref jss

             else do

               hPutStrLn stderr $ "Not all jobs completed successfully: " ++

                         show x

               hPutStrLn stderr "Aborting."

               return False)

-- | Signal handler for graceful termination.

hangleSigInt :: IORef Int -> IO ()

hangleSigInt cref = do

  writeIORef cref 1

  putStrLn ("Cancel request registered, will exit at" ++

            " the end of the current job set...")

-- | Signal handler for immediate termination.

hangleSigTerm :: IORef Int -> IO ()

hangleSigTerm cref = do

  -- update the cref to 2, just for consistency

  writeIORef cref 2

  putStrLn "Double cancel request, exiting now..."

  exitImmediately $ ExitFailure 2

-- | Runs a job set with handling of signals.

runJobSet :: String -> Node.List -> Instance.List -> [JobSet] -> IO Bool

runJobSet master fin_nl il cmd_jobs = do

  cref <- newIORef 0

  mapM_ (\(hnd, sig) -> installHandler sig (Catch (hnd cref)) Nothing)

    [(hangleSigTerm, softwareTermination), (hangleSigInt, keyboardSignal)]

  execWrapper master fin_nl il cref cmd_jobs

-- | Main function.

main :: IO ()

main = do

  cmd_args <- System.getArgs

  (opts, args) <- parseOpts cmd_args "hbal" options

  unless (null args) $ do

         hPutStrLn stderr "Error: this program doesn't take any arguments."

         exitWith $ ExitFailure 1

  let oneline = optOneline opts

      verbose = optVerbose opts

      shownodes = optShowNodes opts

      showinsts = optShowInsts opts

  ini_cdata@(ClusterData gl fixed_nl ilf ctags) <- loadExternalData opts

  let offline_passed = optOffline opts

      all_nodes = Container.elems fixed_nl

      offline_lkp = map (lookupName (map Node.name all_nodes)) offline_passed

      offline_wrong = filter (not . goodLookupResult) offline_lkp

      offline_names = map lrContent offline_lkp

      offline_indices = map Node.idx $

                        filter (\n -> Node.name n `elem` offline_names)

                               all_nodes

      m_cpu = optMcpu opts

      m_dsk = optMdsk opts

      csf = commonSuffix fixed_nl ilf

  when (not (null offline_wrong)) $ do

         hPrintf stderr "Error: Wrong node name(s) set as offline: %s\n"

                     (commaJoin (map lrContent offline_wrong)) :: IO ()

         exitWith $ ExitFailure 1

  let nm = Container.map (\n -> if Node.idx n `elem` offline_indices

                                then Node.setOffline n True

                                else n) fixed_nl

      nlf = Container.map (flip Node.setMdsk m_dsk . flip Node.setMcpu m_cpu)

            nm

  when (not oneline && verbose > 1) $

       putStrLn $ "Loaded cluster tags: " ++ intercalate "," ctags

  when (Container.size ilf == 0) $ do

         (if oneline then putStrLn $ formatOneline 0 0 0

          else printf "Cluster is empty, exiting.\n")

         exitWith ExitSuccess

  let split_insts = Cluster.findSplitInstances nlf ilf

  when (not . null $ split_insts) $ do

    hPutStrLn stderr "Found instances belonging to multiple node groups:"

    mapM_ (\i -> hPutStrLn stderr $ "  " ++ Instance.name i) split_insts

    hPutStrLn stderr "Aborting."

    exitWith $ ExitFailure 1

  let ngroups = Cluster.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

    hPutStrLn stderr "Aborting."

    exitWith $ ExitFailure 1

  maybeSaveData (optSaveCluster opts) "original" "before balancing" ini_cdata

  unless oneline $ printf "Loaded %d nodes, %d instances\n"

             (Container.size nlf)

             (Container.size ilf)

  (gname, (nl, il)) <- case optGroup opts of

    Nothing -> do

         let (gidx, cdata) = head ngroups

             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)

        hPutStrLn stderr "Aborting."

        exitWith $ ExitFailure 1

      Just grp ->

          case lookup (Group.idx grp) ngroups of

            Nothing -> do

              -- TODO: while this is unlikely to happen, log here the

              -- actual group data to help debugging

              hPutStrLn stderr "Internal failure, missing group idx"

              exitWith $ ExitFailure 1

            Just cdata -> return (Group.name grp, cdata)

  unless oneline $ printf "Group size %d nodes, %d instances\n"

             (Container.size nl)

             (Container.size il)

  putStrLn $ "Selected node group: " ++ gname

  when (length csf > 0 && not oneline && verbose > 1) $

       printf "Note: Stripping common suffix of '%s' from names\n" csf

  let (bad_nodes, bad_instances) = Cluster.computeBadItems nl il

  unless (oneline || verbose == 0) $ printf

             "Initial check done: %d bad nodes, %d bad instances.\n"

             (length bad_nodes) (length bad_instances)

  when (length bad_nodes > 0) $

         putStrLn "Cluster is not N+1 happy, continuing but no guarantee \

                  \that the cluster will end N+1 happy."

  maybePrintInsts showinsts "Initial" (Cluster.printInsts nl il)

  maybePrintNodes shownodes "Initial cluster" (Cluster.printNodes nl)

  let ini_cv = Cluster.compCV nl

      ini_tbl = Cluster.Table nl il ini_cv []

      min_cv = optMinScore opts

  when (ini_cv < min_cv) $ do

         (if oneline then

              putStrLn $ formatOneline ini_cv 0 ini_cv

          else printf "Cluster is already well balanced (initial score %.6g,\n\

                      \minimum score %.6g).\nNothing to do, exiting\n"

                      ini_cv min_cv)

         exitWith ExitSuccess

  unless oneline (if verbose > 2 then

                      printf "Initial coefficients: overall %.8f, %s\n"

                      ini_cv (Cluster.printStats nl)

                  else

                      printf "Initial score: %.8f\n" ini_cv)

  unless oneline $ 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 ini_tbl (optMaxLength opts)

                         (optDiskMoves opts)

                         (optInstMoves opts)

                         nmlen imlen [] oneline min_cv

                         (optMinGainLim opts) (optMinGain opts)

                         (optEvacMode opts)

  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, %s\n"

                        fin_cv (Cluster.printStats fin_nl)

                    | otherwise ->

                        printf "Cluster score improved from %.8f to %.8f\n"

                        ini_cv fin_cv ::String

  unless oneline $ putStr sol_msg

  unless (oneline || verbose == 0) $

         printf "Solution length=%d\n" (length ord_plc)

  let cmd_jobs = Cluster.splitJobs cmd_strs

      cmd_data = Cluster.formatCmds cmd_jobs

  when (isJust $ optShowCmds opts) $

       do

         let out_path = fromJust $ optShowCmds opts

         putStrLn ""

         (if out_path == "-" then

              printf "Commands to run to reach the above solution:\n%s"

                     (unlines . map ("  " ++) .

                      filter (/= "  check") .

                      lines $ cmd_data)

          else do

            writeFile out_path (shTemplate ++ cmd_data)

            printf "The commands have been written to file '%s'\n" out_path)

  maybeSaveData (optSaveCluster opts) "balanced" "after balancing"

                (ClusterData gl fin_nl fin_il ctags)

  maybePrintInsts showinsts "Final" (Cluster.printInsts fin_nl fin_il)

  maybePrintNodes shownodes "Final cluster" (Cluster.printNodes fin_nl)

  when (verbose > 3) $ do

         let ini_cs = Cluster.totalResources 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)

  when oneline $

         putStrLn $ formatOneline ini_cv (length ord_plc) fin_cv

  eval <-

      if optExecJobs opts && not (null ord_plc)

      then (case optLuxi opts of

              Nothing -> do

                hPutStrLn stderr "Execution of commands possible only on LUXI"

                return False

              Just master -> runJobSet master fin_nl il cmd_jobs)

      else return True

  unless eval (exitWith (ExitFailure 1))