root / htools / Ganeti / HTools / Types.hs @ 2c9336a4
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{-| Some common types. |
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-} |
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{- |
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Copyright (C) 2009, 2010, 2011 Google Inc. |
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|
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This program is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 2 of the License, or |
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(at your option) any later version. |
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|
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This program is distributed in the hope that it will be useful, but |
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WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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General Public License for more details. |
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|
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You should have received a copy of the GNU General Public License |
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along with this program; if not, write to the Free Software |
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
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02110-1301, USA. |
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-} |
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module Ganeti.HTools.Types |
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( Idx |
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, Ndx |
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, Gdx |
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, NameAssoc |
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, Score |
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, Weight |
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, GroupID |
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, AllocPolicy(..) |
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, allocPolicyFromString |
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, allocPolicyToString |
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, RSpec(..) |
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, DynUtil(..) |
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, zeroUtil |
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, baseUtil |
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, addUtil |
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, subUtil |
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, defVcpuRatio |
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, defReservedDiskRatio |
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, unitMem |
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, unitCpu |
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, unitDsk |
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, unknownField |
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, Placement |
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, IMove(..) |
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, DiskTemplate(..) |
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, diskTemplateToString |
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, diskTemplateFromString |
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, MoveJob |
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, JobSet |
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, Result(..) |
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, isOk |
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, isBad |
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, eitherToResult |
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, Element(..) |
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, FailMode(..) |
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, FailStats |
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, OpResult(..) |
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, opToResult |
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, connTimeout |
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, queryTimeout |
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, EvacMode(..) |
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) where |
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import Control.Monad |
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import qualified Data.Map as M |
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import qualified Text.JSON as JSON |
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|
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import qualified Ganeti.Constants as C |
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-- | The instance index type. |
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type Idx = Int |
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|
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-- | The node index type. |
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type Ndx = Int |
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-- | The group index type. |
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type Gdx = Int |
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-- | The type used to hold name-to-idx mappings. |
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type NameAssoc = M.Map String Int |
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|
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-- | A separate name for the cluster score type. |
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type Score = Double |
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|
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-- | A separate name for a weight metric. |
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type Weight = Double |
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|
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-- | The Group UUID type. |
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type GroupID = String |
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|
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-- | The Group allocation policy type. |
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-- |
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-- Note that the order of constructors is important as the automatic |
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-- Ord instance will order them in the order they are defined, so when |
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-- changing this data type be careful about the interaction with the |
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-- desired sorting order. |
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data AllocPolicy |
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= AllocPreferred -- ^ This is the normal status, the group |
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-- should be used normally during allocations |
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| AllocLastResort -- ^ This group should be used only as |
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-- last-resort, after the preferred groups |
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| AllocUnallocable -- ^ This group must not be used for new |
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-- allocations |
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deriving (Show, Read, Eq, Ord, Enum, Bounded) |
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|
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-- | Convert a string to an alloc policy. |
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allocPolicyFromString :: (Monad m) => String -> m AllocPolicy |
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allocPolicyFromString s = |
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case () of |
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_ | s == C.allocPolicyPreferred -> return AllocPreferred |
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| s == C.allocPolicyLastResort -> return AllocLastResort |
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| s == C.allocPolicyUnallocable -> return AllocUnallocable |
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| otherwise -> fail $ "Invalid alloc policy mode: " ++ s |
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-- | Convert an alloc policy to the Ganeti string equivalent. |
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allocPolicyToString :: AllocPolicy -> String |
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allocPolicyToString AllocPreferred = C.allocPolicyPreferred |
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allocPolicyToString AllocLastResort = C.allocPolicyLastResort |
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allocPolicyToString AllocUnallocable = C.allocPolicyUnallocable |
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|
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instance JSON.JSON AllocPolicy where |
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showJSON = JSON.showJSON . allocPolicyToString |
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readJSON s = case JSON.readJSON s of |
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JSON.Ok s' -> allocPolicyFromString s' |
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JSON.Error e -> JSON.Error $ |
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"Can't parse alloc_policy: " ++ e |
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|
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-- | The resource spec type. |
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data RSpec = RSpec |
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{ rspecCpu :: Int -- ^ Requested VCPUs |
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, rspecMem :: Int -- ^ Requested memory |
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, rspecDsk :: Int -- ^ Requested disk |
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} deriving (Show, Read, Eq) |
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-- | The dynamic resource specs of a machine (i.e. load or load |
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-- capacity, as opposed to size). |
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data DynUtil = DynUtil |
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{ cpuWeight :: Weight -- ^ Standardised CPU usage |
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, memWeight :: Weight -- ^ Standardised memory load |
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, dskWeight :: Weight -- ^ Standardised disk I\/O usage |
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, netWeight :: Weight -- ^ Standardised network usage |
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} deriving (Show, Read, Eq) |
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-- | Initial empty utilisation. |
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zeroUtil :: DynUtil |
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zeroUtil = DynUtil { cpuWeight = 0, memWeight = 0 |
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, dskWeight = 0, netWeight = 0 } |
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-- | Base utilisation (used when no actual utilisation data is |
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-- supplied). |
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baseUtil :: DynUtil |
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baseUtil = DynUtil { cpuWeight = 1, memWeight = 1 |
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, dskWeight = 1, netWeight = 1 } |
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-- | Sum two utilisation records. |
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addUtil :: DynUtil -> DynUtil -> DynUtil |
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addUtil (DynUtil a1 a2 a3 a4) (DynUtil b1 b2 b3 b4) = |
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DynUtil (a1+b1) (a2+b2) (a3+b3) (a4+b4) |
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-- | Substracts one utilisation record from another. |
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subUtil :: DynUtil -> DynUtil -> DynUtil |
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subUtil (DynUtil a1 a2 a3 a4) (DynUtil b1 b2 b3 b4) = |
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DynUtil (a1-b1) (a2-b2) (a3-b3) (a4-b4) |
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-- | The description of an instance placement. It contains the |
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-- instance index, the new primary and secondary node, the move being |
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-- performed and the score of the cluster after the move. |
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type Placement = (Idx, Ndx, Ndx, IMove, Score) |
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-- | An instance move definition. |
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data IMove = Failover -- ^ Failover the instance (f) |
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| ReplacePrimary Ndx -- ^ Replace primary (f, r:np, f) |
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| ReplaceSecondary Ndx -- ^ Replace secondary (r:ns) |
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| ReplaceAndFailover Ndx -- ^ Replace secondary, failover (r:np, f) |
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| FailoverAndReplace Ndx -- ^ Failover, replace secondary (f, r:ns) |
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deriving (Show, Read) |
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-- | Instance disk template type. |
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data DiskTemplate = DTDiskless |
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| DTFile |
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| DTSharedFile |
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| DTPlain |
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| DTBlock |
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| DTDrbd8 |
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deriving (Show, Read, Eq, Enum, Bounded) |
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-- | Converts a DiskTemplate to String. |
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diskTemplateToString :: DiskTemplate -> String |
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diskTemplateToString DTDiskless = C.dtDiskless |
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diskTemplateToString DTFile = C.dtFile |
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diskTemplateToString DTSharedFile = C.dtSharedFile |
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diskTemplateToString DTPlain = C.dtPlain |
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diskTemplateToString DTBlock = C.dtBlock |
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diskTemplateToString DTDrbd8 = C.dtDrbd8 |
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-- | Converts a DiskTemplate from String. |
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diskTemplateFromString :: (Monad m) => String -> m DiskTemplate |
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diskTemplateFromString s = |
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case () of |
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_ | s == C.dtDiskless -> return DTDiskless |
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| s == C.dtFile -> return DTFile |
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| s == C.dtSharedFile -> return DTSharedFile |
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| s == C.dtPlain -> return DTPlain |
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| s == C.dtBlock -> return DTBlock |
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| s == C.dtDrbd8 -> return DTDrbd8 |
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| otherwise -> fail $ "Invalid disk template: " ++ s |
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instance JSON.JSON DiskTemplate where |
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showJSON = JSON.showJSON . diskTemplateToString |
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readJSON s = case JSON.readJSON s of |
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JSON.Ok s' -> diskTemplateFromString s' |
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JSON.Error e -> JSON.Error $ |
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"Can't parse disk_template as string: " ++ e |
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-- | Formatted solution output for one move (involved nodes and |
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-- commands. |
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type MoveJob = ([Ndx], Idx, IMove, [String]) |
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-- | Unknown field in table output. |
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unknownField :: String |
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unknownField = "<unknown field>" |
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-- | A list of command elements. |
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type JobSet = [MoveJob] |
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-- | Connection timeout (when using non-file methods). |
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connTimeout :: Int |
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connTimeout = 15 |
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-- | The default timeout for queries (when using non-file methods). |
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queryTimeout :: Int |
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queryTimeout = 60 |
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-- | Default vcpu-to-pcpu ratio (randomly chosen value). |
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defVcpuRatio :: Double |
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defVcpuRatio = 64 |
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-- | Default max disk usage ratio. |
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defReservedDiskRatio :: Double |
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defReservedDiskRatio = 0 |
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-- | Base memory unit. |
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unitMem :: Int |
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unitMem = 64 |
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-- | Base disk unit. |
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unitDsk :: Int |
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unitDsk = 256 |
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-- | Base vcpus unit. |
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unitCpu :: Int |
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unitCpu = 1 |
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-- | This is similar to the JSON library Result type - /very/ similar, |
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-- but we want to use it in multiple places, so we abstract it into a |
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-- mini-library here. |
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-- |
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-- The failure value for this monad is simply a string. |
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data Result a |
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= Bad String |
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| Ok a |
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deriving (Show, Read, Eq) |
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instance Monad Result where |
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(>>=) (Bad x) _ = Bad x |
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(>>=) (Ok x) fn = fn x |
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return = Ok |
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fail = Bad |
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instance MonadPlus Result where |
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mzero = Bad "zero Result when used as MonadPlus" |
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-- for mplus, when we 'add' two Bad values, we concatenate their |
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-- error descriptions |
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(Bad x) `mplus` (Bad y) = Bad (x ++ "; " ++ y) |
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(Bad _) `mplus` x = x |
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x@(Ok _) `mplus` _ = x |
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-- | Simple checker for whether a 'Result' is OK. |
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isOk :: Result a -> Bool |
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isOk (Ok _) = True |
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isOk _ = False |
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-- | Simple checker for whether a 'Result' is a failure. |
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isBad :: Result a -> Bool |
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isBad = not . isOk |
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-- | Converter from Either String to 'Result'. |
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eitherToResult :: Either String a -> Result a |
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eitherToResult (Left s) = Bad s |
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eitherToResult (Right v) = Ok v |
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-- | Reason for an operation's falure. |
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data FailMode = FailMem -- ^ Failed due to not enough RAM |
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| FailDisk -- ^ Failed due to not enough disk |
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| FailCPU -- ^ Failed due to not enough CPU capacity |
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| FailN1 -- ^ Failed due to not passing N1 checks |
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| FailTags -- ^ Failed due to tag exclusion |
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deriving (Eq, Enum, Bounded, Show, Read) |
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-- | List with failure statistics. |
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type FailStats = [(FailMode, Int)] |
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-- | Either-like data-type customized for our failure modes. |
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-- |
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-- The failure values for this monad track the specific allocation |
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-- failures, so this is not a general error-monad (compare with the |
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-- 'Result' data type). One downside is that this type cannot encode a |
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-- generic failure mode, hence 'fail' for this monad is not defined |
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-- and will cause an exception. |
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data OpResult a = OpFail FailMode -- ^ Failed operation |
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| OpGood a -- ^ Success operation |
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deriving (Show, Read) |
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instance Monad OpResult where |
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(OpGood x) >>= fn = fn x |
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(OpFail y) >>= _ = OpFail y |
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return = OpGood |
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-- | Conversion from 'OpResult' to 'Result'. |
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opToResult :: OpResult a -> Result a |
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opToResult (OpFail f) = Bad $ show f |
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opToResult (OpGood v) = Ok v |
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-- | A generic class for items that have updateable names and indices. |
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class Element a where |
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-- | Returns the name of the element |
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nameOf :: a -> String |
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-- | Returns all the known names of the element |
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allNames :: a -> [String] |
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-- | Returns the index of the element |
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idxOf :: a -> Int |
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-- | Updates the alias of the element |
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setAlias :: a -> String -> a |
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-- | Compute the alias by stripping a given suffix (domain) from |
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-- the name |
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computeAlias :: String -> a -> a |
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computeAlias dom e = setAlias e alias |
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where alias = take (length name - length dom) name |
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name = nameOf e |
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-- | Updates the index of the element |
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setIdx :: a -> Int -> a |
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-- | The iallocator node-evacuate evac_mode type. |
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data EvacMode = ChangePrimary |
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| ChangeSecondary |
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| ChangeAll |
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deriving (Show, Read) |
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instance JSON.JSON EvacMode where |
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showJSON mode = case mode of |
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ChangeAll -> JSON.showJSON C.iallocatorNevacAll |
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ChangePrimary -> JSON.showJSON C.iallocatorNevacPri |
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ChangeSecondary -> JSON.showJSON C.iallocatorNevacSec |
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readJSON v = |
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case JSON.readJSON v of |
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JSON.Ok s | s == C.iallocatorNevacAll -> return ChangeAll |
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| s == C.iallocatorNevacPri -> return ChangePrimary |
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| s == C.iallocatorNevacSec -> return ChangeSecondary |
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| otherwise -> fail $ "Invalid evacuate mode " ++ s |
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JSON.Error e -> JSON.Error $ |
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"Can't parse evacuate mode as string: " ++ e |