root / htools / Ganeti / HTools / Instance.hs @ 084565ac
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{-| Module describing an instance. |
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|
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The instance data type holds very few fields, the algorithm |
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intelligence is in the "Node" and "Cluster" modules. |
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|
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-} |
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{- |
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|
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Copyright (C) 2009, 2010, 2011, 2012 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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-} |
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module Ganeti.HTools.Instance |
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( Instance(..) |
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, AssocList |
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, List |
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, create |
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, isRunning |
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, isOffline |
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, notOffline |
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, instanceDown |
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, usesSecMem |
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, applyIfOnline |
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, setIdx |
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, setName |
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, setAlias |
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, setPri |
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, setSec |
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, setBoth |
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, setMovable |
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, specOf |
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, instBelowISpec |
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, instAboveISpec |
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, instMatchesPolicy |
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, shrinkByType |
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, localStorageTemplates |
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, hasSecondary |
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, requiredNodes |
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, allNodes |
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, usesLocalStorage |
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) where |
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import qualified Ganeti.HTools.Types as T |
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import qualified Ganeti.HTools.Container as Container |
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import Ganeti.HTools.Utils |
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|
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-- * Type declarations |
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-- | The instance type. |
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data Instance = Instance |
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{ name :: String -- ^ The instance name |
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, alias :: String -- ^ The shortened name |
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, mem :: Int -- ^ Memory of the instance |
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, dsk :: Int -- ^ Disk size of instance |
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, vcpus :: Int -- ^ Number of VCPUs |
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, runSt :: T.InstanceStatus -- ^ Original run status |
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, pNode :: T.Ndx -- ^ Original primary node |
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, sNode :: T.Ndx -- ^ Original secondary node |
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, idx :: T.Idx -- ^ Internal index |
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, util :: T.DynUtil -- ^ Dynamic resource usage |
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, movable :: Bool -- ^ Can and should the instance be moved? |
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, autoBalance :: Bool -- ^ Is the instance auto-balanced? |
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, tags :: [String] -- ^ List of instance tags |
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, diskTemplate :: T.DiskTemplate -- ^ The disk template of the instance |
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} deriving (Show, Read, Eq) |
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instance T.Element Instance where |
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nameOf = name |
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idxOf = idx |
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setAlias = setAlias |
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setIdx = setIdx |
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allNames n = [name n, alias n] |
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|
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-- | Check if instance is running. |
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isRunning :: Instance -> Bool |
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isRunning (Instance {runSt = T.Running}) = True |
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isRunning (Instance {runSt = T.ErrorUp}) = True |
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isRunning _ = False |
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-- | Check if instance is offline. |
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isOffline :: Instance -> Bool |
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isOffline (Instance {runSt = T.AdminOffline}) = True |
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isOffline _ = False |
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-- | Helper to check if the instance is not offline. |
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notOffline :: Instance -> Bool |
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notOffline = not . isOffline |
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-- | Check if instance is down. |
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instanceDown :: Instance -> Bool |
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instanceDown inst | isRunning inst = False |
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instanceDown inst | isOffline inst = False |
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instanceDown _ = True |
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-- | Apply the function if the instance is online. Otherwise use |
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-- the initial value |
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applyIfOnline :: Instance -> (a -> a) -> a -> a |
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applyIfOnline = applyIf . notOffline |
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-- | Helper for determining whether an instance's memory needs to be |
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-- taken into account for secondary memory reservation. |
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usesSecMem :: Instance -> Bool |
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usesSecMem inst = notOffline inst && autoBalance inst |
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-- | Constant holding the local storage templates. |
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-- |
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-- /Note:/ Currently Ganeti only exports node total/free disk space |
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-- for LVM-based storage; file-based storage is ignored in this model, |
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-- so even though file-based storage uses in reality disk space on the |
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-- node, in our model it won't affect it and we can't compute whether |
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-- there is enough disk space for a file-based instance. Therefore we |
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-- will treat this template as \'foreign\' storage. |
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localStorageTemplates :: [T.DiskTemplate] |
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localStorageTemplates = [ T.DTDrbd8, T.DTPlain ] |
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-- | Constant holding the movable disk templates. |
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-- |
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-- This only determines the initial 'movable' state of the |
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-- instance. Further the movable state can be restricted more due to |
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-- user choices, etc. |
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movableDiskTemplates :: [T.DiskTemplate] |
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movableDiskTemplates = [ T.DTDrbd8, T.DTBlock, T.DTSharedFile ] |
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-- | A simple name for the int, instance association list. |
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type AssocList = [(T.Idx, Instance)] |
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-- | A simple name for an instance map. |
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type List = Container.Container Instance |
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-- * Initialization |
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-- | Create an instance. |
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-- |
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-- Some parameters are not initialized by function, and must be set |
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-- later (via 'setIdx' for example). |
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create :: String -> Int -> Int -> Int -> T.InstanceStatus |
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-> [String] -> Bool -> T.Ndx -> T.Ndx -> T.DiskTemplate -> Instance |
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create name_init mem_init dsk_init vcpus_init run_init tags_init |
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auto_balance_init pn sn dt = |
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Instance { name = name_init |
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, alias = name_init |
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, mem = mem_init |
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, dsk = dsk_init |
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, vcpus = vcpus_init |
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, runSt = run_init |
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, pNode = pn |
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, sNode = sn |
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, idx = -1 |
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, util = T.baseUtil |
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, tags = tags_init |
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, movable = supportsMoves dt |
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, autoBalance = auto_balance_init |
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, diskTemplate = dt |
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} |
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-- | Changes the index. |
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-- |
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-- This is used only during the building of the data structures. |
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setIdx :: Instance -- ^ The original instance |
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-> T.Idx -- ^ New index |
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-> Instance -- ^ The modified instance |
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setIdx t i = t { idx = i } |
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-- | Changes the name. |
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-- |
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-- This is used only during the building of the data structures. |
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setName :: Instance -- ^ The original instance |
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-> String -- ^ New name |
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-> Instance -- ^ The modified instance |
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setName t s = t { name = s, alias = s } |
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-- | Changes the alias. |
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-- |
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-- This is used only during the building of the data structures. |
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setAlias :: Instance -- ^ The original instance |
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-> String -- ^ New alias |
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-> Instance -- ^ The modified instance |
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setAlias t s = t { alias = s } |
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-- * Update functions |
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-- | Changes the primary node of the instance. |
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setPri :: Instance -- ^ the original instance |
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-> T.Ndx -- ^ the new primary node |
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-> Instance -- ^ the modified instance |
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setPri t p = t { pNode = p } |
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-- | Changes the secondary node of the instance. |
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setSec :: Instance -- ^ the original instance |
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-> T.Ndx -- ^ the new secondary node |
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-> Instance -- ^ the modified instance |
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setSec t s = t { sNode = s } |
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-- | Changes both nodes of the instance. |
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setBoth :: Instance -- ^ the original instance |
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-> T.Ndx -- ^ new primary node index |
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-> T.Ndx -- ^ new secondary node index |
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-> Instance -- ^ the modified instance |
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setBoth t p s = t { pNode = p, sNode = s } |
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-- | Sets the movable flag on an instance. |
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setMovable :: Instance -- ^ The original instance |
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-> Bool -- ^ New movable flag |
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-> Instance -- ^ The modified instance |
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setMovable t m = t { movable = m } |
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-- | Try to shrink the instance based on the reason why we can't |
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-- allocate it. |
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shrinkByType :: Instance -> T.FailMode -> T.Result Instance |
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shrinkByType inst T.FailMem = let v = mem inst - T.unitMem |
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in if v < T.unitMem |
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then T.Bad "out of memory" |
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else T.Ok inst { mem = v } |
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shrinkByType inst T.FailDisk = let v = dsk inst - T.unitDsk |
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in if v < T.unitDsk |
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then T.Bad "out of disk" |
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else T.Ok inst { dsk = v } |
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shrinkByType inst T.FailCPU = let v = vcpus inst - T.unitCpu |
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in if v < T.unitCpu |
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then T.Bad "out of vcpus" |
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else T.Ok inst { vcpus = v } |
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shrinkByType _ f = T.Bad $ "Unhandled failure mode " ++ show f |
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-- | Return the spec of an instance. |
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specOf :: Instance -> T.RSpec |
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specOf Instance { mem = m, dsk = d, vcpus = c } = |
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T.RSpec { T.rspecCpu = c, T.rspecMem = m, T.rspecDsk = d } |
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-- | Checks if an instance is smaller than a given spec. Returns |
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-- OpGood for a correct spec, otherwise OpFail one of the possible |
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-- failure modes. |
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instBelowISpec :: Instance -> T.ISpec -> T.OpResult () |
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instBelowISpec inst ispec |
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| mem inst > T.iSpecMemorySize ispec = T.OpFail T.FailMem |
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| dsk inst > T.iSpecDiskSize ispec = T.OpFail T.FailDisk |
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| vcpus inst > T.iSpecCpuCount ispec = T.OpFail T.FailCPU |
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| otherwise = T.OpGood () |
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-- | Checks if an instance is bigger than a given spec. |
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instAboveISpec :: Instance -> T.ISpec -> T.OpResult () |
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instAboveISpec inst ispec |
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| mem inst < T.iSpecMemorySize ispec = T.OpFail T.FailMem |
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| dsk inst < T.iSpecDiskSize ispec = T.OpFail T.FailDisk |
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| vcpus inst < T.iSpecCpuCount ispec = T.OpFail T.FailCPU |
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| otherwise = T.OpGood () |
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-- | Checks if an instance matches a policy. |
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instMatchesPolicy :: Instance -> T.IPolicy -> T.OpResult () |
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instMatchesPolicy inst ipol = do |
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instAboveISpec inst (T.iPolicyMinSpec ipol) |
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instBelowISpec inst (T.iPolicyMaxSpec ipol) |
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if (diskTemplate inst `elem` T.iPolicyDiskTemplates ipol) |
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then T.OpGood () |
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else T.OpFail T.FailDisk |
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-- | Checks whether the instance uses a secondary node. |
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-- |
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-- /Note:/ This should be reconciled with @'sNode' == |
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-- 'Node.noSecondary'@. |
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hasSecondary :: Instance -> Bool |
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hasSecondary = (== T.DTDrbd8) . diskTemplate |
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-- | Computed the number of nodes for a given disk template. |
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requiredNodes :: T.DiskTemplate -> Int |
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requiredNodes T.DTDrbd8 = 2 |
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requiredNodes _ = 1 |
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-- | Computes all nodes of an instance. |
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allNodes :: Instance -> [T.Ndx] |
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allNodes inst = case diskTemplate inst of |
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T.DTDrbd8 -> [pNode inst, sNode inst] |
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_ -> [pNode inst] |
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-- | Checks whether a given disk template uses local storage. |
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usesLocalStorage :: Instance -> Bool |
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usesLocalStorage = (`elem` localStorageTemplates) . diskTemplate |
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-- | Checks whether a given disk template supported moves. |
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supportsMoves :: T.DiskTemplate -> Bool |
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supportsMoves = (`elem` movableDiskTemplates) |