Synnefo » snf-ganeti » ganeti-local

{-# LANGUAGE TemplateHaskell #-}

{-| Some common types.

-}

{-

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.Types

  ( Idx

  , Ndx

  , Gdx

  , NameAssoc

  , Score

  , Weight

  , GroupID

  , AllocPolicy(..)

  , allocPolicyFromRaw

  , allocPolicyToRaw

  , InstanceStatus(..)

  , instanceStatusFromRaw

  , instanceStatusToRaw

  , RSpec(..)

  , DynUtil(..)

  , zeroUtil

  , baseUtil

  , addUtil

  , subUtil

  , defVcpuRatio

  , defReservedDiskRatio

  , unitMem

  , unitCpu

  , unitDsk

  , unknownField

  , Placement

  , IMove(..)

  , DiskTemplate(..)

  , diskTemplateToRaw

  , diskTemplateFromRaw

  , MoveJob

  , JobSet

  , Result(..)

  , isOk

  , isBad

  , eitherToResult

  , Element(..)

  , FailMode(..)

  , FailStats

  , OpResult(..)

  , opToResult

  , connTimeout

  , queryTimeout

  , EvacMode(..)

  ) where

import Control.Monad

import qualified Data.Map as M

import qualified Text.JSON as JSON

import qualified Ganeti.Constants as C

import qualified Ganeti.THH as THH

-- | The instance index type.

type Idx = Int

-- | The node index type.

type Ndx = Int

-- | The group index type.

type Gdx = Int

-- | The type used to hold name-to-idx mappings.

type NameAssoc = M.Map String Int

-- | A separate name for the cluster score type.

type Score = Double

-- | A separate name for a weight metric.

type Weight = Double

-- | The Group UUID type.

type GroupID = String

-- | The Group allocation policy type.

--

-- Note that the order of constructors is important as the automatic

-- Ord instance will order them in the order they are defined, so when

-- changing this data type be careful about the interaction with the

-- desired sorting order.

$(THH.declareSADT "AllocPolicy"

       [ ("AllocPreferred",   'C.allocPolicyPreferred)

       , ("AllocLastResort",  'C.allocPolicyLastResort)

       , ("AllocUnallocable", 'C.allocPolicyUnallocable)

       ])

$(THH.makeJSONInstance ''AllocPolicy)

-- | The Instance real state type.

$(THH.declareSADT "InstanceStatus"

       [ ("AdminDown", 'C.inststAdmindown)

       , ("AdminOffline", 'C.inststAdminoffline)

       , ("ErrorDown", 'C.inststErrordown)

       , ("ErrorUp", 'C.inststErrorup)

       , ("NodeDown", 'C.inststNodedown)

       , ("NodeOffline", 'C.inststNodeoffline)

       , ("Running", 'C.inststRunning)

       , ("WrongNode", 'C.inststWrongnode)

       ])

$(THH.makeJSONInstance ''InstanceStatus)

-- | The resource spec type.

data RSpec = RSpec

  { rspecCpu  :: Int  -- ^ Requested VCPUs

  , rspecMem  :: Int  -- ^ Requested memory

  , rspecDsk  :: Int  -- ^ Requested disk

  } deriving (Show, Read, Eq)

-- | The dynamic resource specs of a machine (i.e. load or load

-- capacity, as opposed to size).

data DynUtil = DynUtil

  { cpuWeight :: Weight -- ^ Standardised CPU usage

  , memWeight :: Weight -- ^ Standardised memory load

  , dskWeight :: Weight -- ^ Standardised disk I\/O usage

  , netWeight :: Weight -- ^ Standardised network usage

  } deriving (Show, Read, Eq)

-- | Initial empty utilisation.

zeroUtil :: DynUtil

zeroUtil = DynUtil { cpuWeight = 0, memWeight = 0

                   , dskWeight = 0, netWeight = 0 }

-- | Base utilisation (used when no actual utilisation data is

-- supplied).

baseUtil :: DynUtil

baseUtil = DynUtil { cpuWeight = 1, memWeight = 1

                   , dskWeight = 1, netWeight = 1 }

-- | Sum two utilisation records.

addUtil :: DynUtil -> DynUtil -> DynUtil

addUtil (DynUtil a1 a2 a3 a4) (DynUtil b1 b2 b3 b4) =

  DynUtil (a1+b1) (a2+b2) (a3+b3) (a4+b4)

-- | Substracts one utilisation record from another.

subUtil :: DynUtil -> DynUtil -> DynUtil

subUtil (DynUtil a1 a2 a3 a4) (DynUtil b1 b2 b3 b4) =

  DynUtil (a1-b1) (a2-b2) (a3-b3) (a4-b4)

-- | The description of an instance placement. It contains the

-- instance index, the new primary and secondary node, the move being

-- performed and the score of the cluster after the move.

type Placement = (Idx, Ndx, Ndx, IMove, Score)

-- | An instance move definition.

data IMove = Failover                -- ^ Failover the instance (f)

           | ReplacePrimary Ndx      -- ^ Replace primary (f, r:np, f)

           | ReplaceSecondary Ndx    -- ^ Replace secondary (r:ns)

           | ReplaceAndFailover Ndx  -- ^ Replace secondary, failover (r:np, f)

           | FailoverAndReplace Ndx  -- ^ Failover, replace secondary (f, r:ns)

             deriving (Show, Read)

-- | Instance disk template type.

$(THH.declareSADT "DiskTemplate"

       [ ("DTDiskless",   'C.dtDiskless)

       , ("DTFile",       'C.dtFile)

       , ("DTSharedFile", 'C.dtSharedFile)

       , ("DTPlain",      'C.dtPlain)

       , ("DTBlock",      'C.dtBlock)

       , ("DTDrbd8",      'C.dtDrbd8)

       ])

$(THH.makeJSONInstance ''DiskTemplate)

-- | Formatted solution output for one move (involved nodes and

-- commands.

type MoveJob = ([Ndx], Idx, IMove, [String])

-- | Unknown field in table output.

unknownField :: String

unknownField = "<unknown field>"

-- | A list of command elements.

type JobSet = [MoveJob]

-- | Connection timeout (when using non-file methods).

connTimeout :: Int

connTimeout = 15

-- | The default timeout for queries (when using non-file methods).

queryTimeout :: Int

queryTimeout = 60

-- | Default vcpu-to-pcpu ratio (randomly chosen value).

defVcpuRatio :: Double

defVcpuRatio = 64

-- | Default max disk usage ratio.

defReservedDiskRatio :: Double

defReservedDiskRatio = 0

-- | Base memory unit.

unitMem :: Int

unitMem = 64

-- | Base disk unit.

unitDsk :: Int

unitDsk = 256

-- | Base vcpus unit.

unitCpu :: Int

unitCpu = 1

-- | This is similar to the JSON library Result type - /very/ similar,

-- but we want to use it in multiple places, so we abstract it into a

-- mini-library here.

--

-- The failure value for this monad is simply a string.

data Result a

    = Bad String

    | Ok a

    deriving (Show, Read, Eq)

instance Monad Result where

  (>>=) (Bad x) _ = Bad x

  (>>=) (Ok x) fn = fn x

  return = Ok

  fail = Bad

instance MonadPlus Result where

  mzero = Bad "zero Result when used as MonadPlus"

  -- for mplus, when we 'add' two Bad values, we concatenate their

  -- error descriptions

  (Bad x) `mplus` (Bad y) = Bad (x ++ "; " ++ y)

  (Bad _) `mplus` x = x

  x@(Ok _) `mplus` _ = x

-- | Simple checker for whether a 'Result' is OK.

isOk :: Result a -> Bool

isOk (Ok _) = True

isOk _ = False

-- | Simple checker for whether a 'Result' is a failure.

isBad :: Result a  -> Bool

isBad = not . isOk

-- | Converter from Either String to 'Result'.

eitherToResult :: Either String a -> Result a

eitherToResult (Left s) = Bad s

eitherToResult (Right v) = Ok v

-- | Reason for an operation's falure.

data FailMode = FailMem  -- ^ Failed due to not enough RAM

              | FailDisk -- ^ Failed due to not enough disk

              | FailCPU  -- ^ Failed due to not enough CPU capacity

              | FailN1   -- ^ Failed due to not passing N1 checks

              | FailTags -- ^ Failed due to tag exclusion

                deriving (Eq, Enum, Bounded, Show, Read)

-- | List with failure statistics.

type FailStats = [(FailMode, Int)]

-- | Either-like data-type customized for our failure modes.

--

-- The failure values for this monad track the specific allocation

-- failures, so this is not a general error-monad (compare with the

-- 'Result' data type). One downside is that this type cannot encode a

-- generic failure mode, hence 'fail' for this monad is not defined

-- and will cause an exception.

data OpResult a = OpFail FailMode -- ^ Failed operation

                | OpGood a        -- ^ Success operation

                  deriving (Show, Read)

instance Monad OpResult where

  (OpGood x) >>= fn = fn x

  (OpFail y) >>= _ = OpFail y

  return = OpGood

-- | Conversion from 'OpResult' to 'Result'.

opToResult :: OpResult a -> Result a

opToResult (OpFail f) = Bad $ show f

opToResult (OpGood v) = Ok v

-- | A generic class for items that have updateable names and indices.

class Element a where

  -- | Returns the name of the element

  nameOf  :: a -> String

  -- | Returns all the known names of the element

  allNames :: a -> [String]

  -- | Returns the index of the element

  idxOf   :: a -> Int

  -- | Updates the alias of the element

  setAlias :: a -> String -> a

  -- | Compute the alias by stripping a given suffix (domain) from

  -- the name

  computeAlias :: String -> a -> a

  computeAlias dom e = setAlias e alias

    where alias = take (length name - length dom) name

          name = nameOf e

  -- | Updates the index of the element

  setIdx  :: a -> Int -> a

-- | The iallocator node-evacuate evac_mode type.

$(THH.declareSADT "EvacMode"

       [ ("ChangePrimary",   'C.iallocatorNevacPri)

       , ("ChangeSecondary", 'C.iallocatorNevacSec)

       , ("ChangeAll",       'C.iallocatorNevacAll)

       ])

$(THH.makeJSONInstance ''EvacMode)