Safe Haskell	Safe-Infered

Ganeti.HTools.Cluster

Contents

Types
Utility functions
Balancing functions
Allocation functions
Formatting functions
Node group functions

Description

Implementation of cluster-wide logic.

This module holds all pure cluster-logic; I/O related functionality goes into the Main module for the individual binaries.

Synopsis

Types

data AllocSolution Source

Allocation/relocation solution.

Constructors

AllocSolution
Fields asFailures :: [FailMode] Failure counts asAllocs :: Int Good allocation count asSolution :: Maybe AllocElement The actual allocation result asLog :: [String] Informational messages

data EvacSolution Source

Node evacuation/group change iallocator result type. This result type consists of actual opcodes (a restricted subset) that are transmitted back to Ganeti.

Constructors

EvacSolution
Fields esMoved :: [(Idx, Gdx, [Ndx])] Instances moved successfully esFailed :: [(Idx, String)] Instances which were not relocated esOpCodes :: [[OpCode]] List of jobs

Instances

Show EvacSolution

type AllocResult = (FailStats, List, List, [Instance], [CStats])Source

Allocation results, as used in iterateAlloc and tieredAlloc.

type AllocSolutionList = [(Instance, AllocSolution)]Source

Type alias for easier handling.

type AllocNodes = Either [Ndx] [(Ndx, [Ndx])]Source

emptyAllocSolution :: AllocSolution Source

emptyEvacSolution :: EvacSolution Source

data Table Source

The complete state for the balancing solution.

Constructors

Table List List Score [Placement]

Instances

Show Table

data CStats Source

Cluster statistics data type.

Constructors

CStats

Fields

csFmem :: Integer: Cluster free mem
csFdsk :: Integer: Cluster free disk
csAmem :: Integer: Cluster allocatable mem
csAdsk :: Integer: Cluster allocatable disk
csAcpu :: Integer: Cluster allocatable cpus
csMmem :: Integer: Max node allocatable mem
csMdsk :: Integer: Max node allocatable disk
csMcpu :: Integer: Max node allocatable cpu
csImem :: Integer: Instance used mem
csIdsk :: Integer: Instance used disk
csIcpu :: Integer: Instance used cpu
csTmem :: Double: Cluster total mem
csTdsk :: Double: Cluster total disk
csTcpu :: Double: Cluster total cpus
csVcpu :: Integer: Cluster total virtual cpus
csNcpu :: Double: Equivalent to csIcpu but in terms of physical CPUs, i.e. normalised used phys CPUs
csXmem :: Integer: Unnacounted for mem
csNmem :: Integer: Node own memory
csScore :: Score: The cluster score
csNinst :: Int: The total number of instances

Instances

Show CStats

type AllocMethod Source

Arguments

= List	Node list
-> List	Instance list
-> Maybe Int	Optional allocation limit
-> Instance	Instance spec for allocation
-> AllocNodes	Which nodes we should allocate on
-> [Instance]	Allocated instances
-> [CStats]	Running cluster stats
-> Result AllocResult	Allocation result

A simple type for allocation functions.

type EvacInnerState = Either String (List, Instance, Score, Ndx)Source

Utility functions

verifyN1 :: [Node] -> [Node]Source

computeBadItems :: List -> List -> ([Node], [Instance])Source

Computes the pair of bad nodes and instances.

The bad node list is computed via a simple verifyN1 check, and the bad instance list is the list of primary and secondary instances of those nodes.

instanceNodes :: List -> Instance -> (Ndx, Ndx, Node, Node)Source

emptyCStats :: CStats Source

updateCStats :: CStats -> Node -> CStats Source

totalResources :: List -> CStats Source

Compute the total free disk and memory in the cluster.

computeAllocationDelta :: CStats -> CStats -> AllocStats Source

Compute the delta between two cluster state.

This is used when doing allocations, to understand better the available cluster resources. The return value is a triple of the current used values, the delta that was still allocated, and what was left unallocated.

detailedCVInfo :: [(Double, String)]Source

detailedCVWeights :: [Double]Source

compDetailedCV :: [Node] -> [Double]Source

Compute the mem and disk covariance.

compCVNodes :: [Node] -> DoubleSource

Compute the total variance.

compCV :: List -> DoubleSource

Wrapper over compCVNodes for callers that have a List.

getOnline :: List -> [Node]Source

Balancing functions

compareTables :: Table -> Table -> Table Source

applyMove :: List -> Instance -> IMove -> OpResult (List, Instance, Ndx, Ndx)Source

allocateOnSingle :: List -> Instance -> Ndx -> OpResult AllocElement Source

allocateOnPair :: List -> Instance -> Ndx -> Ndx -> OpResult AllocElement Source

checkSingleStep :: Table -> Instance -> Table -> IMove -> Table Source

possibleMoves :: MirrorType -> Bool -> Bool -> Ndx -> [IMove]Source

checkInstanceMove :: [Ndx] -> Bool -> Bool -> Table -> Instance -> Table Source

checkMove Source

Arguments

:: [Ndx]	Allowed target node indices
-> Bool	Whether disk moves are allowed
-> Bool	Whether instance moves are allowed
-> Table	The current solution
-> [Instance]	List of instances still to move
-> Table	The new solution

Compute the best next move.

doNextBalance Source

Arguments

:: Table	The starting table
-> Int	Remaining length
-> Score	Score at which to stop
-> Bool	The resulting table and commands

Check if we are allowed to go deeper in the balancing.

tryBalance Source

Arguments

:: Table	The starting table
-> Bool	Allow disk moves
-> Bool	Allow instance moves
-> Bool	Only evacuate moves
-> Score	Min gain threshold
-> Score	Min gain
-> Maybe Table	The resulting table and commands

Run a balance move.

Allocation functions

collapseFailures :: [FailMode] -> FailStats Source

Build failure stats out of a list of failures.

bestAllocElement :: Maybe AllocElement -> Maybe AllocElement -> Maybe AllocElement Source

concatAllocs :: AllocSolution -> OpResult AllocElement -> AllocSolution Source

sumAllocs :: AllocSolution -> AllocSolution -> AllocSolution Source

describeSolution :: AllocSolution -> StringSource

annotateSolution :: AllocSolution -> AllocSolution Source

reverseEvacSolution :: EvacSolution -> EvacSolution Source

genAllocNodes Source

Arguments

:: List	Group list
-> List	The node map
-> Int	The number of nodes required
-> Bool	Whether to drop or not unallocable nodes
-> Result AllocNodes	The (monadic) result

Generate the valid node allocation singles or pairs for a new instance.

tryAlloc Source

Arguments

:: Monad m
=> List	The node list
-> List	The instance list
-> Instance	The instance to allocate
-> AllocNodes	The allocation targets
-> m AllocSolution	Possible solution list

Try to allocate an instance on the cluster.

solutionDescription :: List -> (Gdx, Result AllocSolution) -> [String]Source

filterMGResults :: List -> [(Gdx, Result AllocSolution)] -> [(Gdx, AllocSolution)]Source

sortMGResults :: List -> [(Gdx, AllocSolution)] -> [(Gdx, AllocSolution)]Source

findBestAllocGroup :: List -> List -> List -> Maybe [Gdx] -> Instance -> Int -> Result (Gdx, AllocSolution, [String])Source

tryMGAlloc Source

Arguments

:: List	The group list
-> List	The node list
-> List	The instance list
-> Instance	The instance to allocate
-> Int	Required number of nodes
-> Result AllocSolution	Possible solution list

Try to allocate an instance on a multi-group cluster.

updateIl :: List -> Maybe AllocElement -> List Source

extractNl :: List -> Maybe AllocElement -> List Source

allocList Source

Arguments

:: List	The group list
-> List	The node list
-> List	The instance list
-> [(Instance, Int)]	The instance to allocate
-> AllocSolutionList	Possible solution list
-> Result (List, List, AllocSolutionList)	The final solution list

Try to allocate a list of instances on a multi-group cluster.

failOnSecondaryChange :: Monad m => EvacMode -> DiskTemplate -> m ()Source

nodeEvacInstance :: List -> List -> EvacMode -> Instance -> Gdx -> [Ndx] -> Result (List, List, [OpCode])Source

evacOneNodeOnly :: List -> List -> Instance -> Gdx -> [Ndx] -> Result (List, List, [OpCode])Source

evacOneNodeInner :: List -> Instance -> Gdx -> (Ndx -> IMove) -> EvacInnerState -> Ndx -> EvacInnerState Source

evacDrbdAllInner :: List -> List -> Instance -> Gdx -> (Ndx, Ndx) -> Result (List, List, [OpCode], Score)Source

availableGroupNodes :: [(Gdx, [Ndx])] -> IntSet -> Gdx -> Result [Ndx]Source

updateEvacSolution :: (List, List, EvacSolution) -> Idx -> Result (List, List, [OpCode]) -> (List, List, EvacSolution)Source

tryNodeEvac Source

Arguments

:: List	The cluster groups
-> List	The node list (cluster-wide, not per group)
-> List	Instance list (cluster-wide)
-> EvacMode	The evacuation mode
-> [Idx]	List of instance (indices) to be evacuated
-> Result (List, List, EvacSolution)

Node-evacuation IAllocator mode main function.

tryChangeGroup Source

Arguments

:: List	The cluster groups
-> List	The node list (cluster-wide)
-> List	Instance list (cluster-wide)
-> [Gdx]	Target groups; if empty, any groups not being evacuated
-> [Idx]	List of instance (indices) to be evacuated
-> Result (List, List, EvacSolution)

Change-group IAllocator mode main function.

This is very similar to tryNodeEvac, the only difference is that we don't choose as target group the current instance group, but instead:

at the start of the function, we compute which are the target groups; either no groups were passed in, in which case we choose all groups out of which we don't evacuate instance, or there were some groups passed, in which case we use those
for each instance, we use findBestAllocGroup to choose the best group to hold the instance, and then we do what tryNodeEvac does, except for this group instead of the current instance group.

Note that the correct behaviour of this function relies on the function nodeEvacInstance to be able to do correctly both intra-group and inter-group moves when passed the ChangeAll mode.

iterateAlloc :: AllocMethod Source

Standard-sized allocation method.

This places instances of the same size on the cluster until we're out of space. The result will be a list of identically-sized instances.

tieredAlloc :: AllocMethod Source

Tiered allocation method.

This places instances on the cluster, and decreases the spec until we can allocate again. The result will be a list of decreasing instance specs.

Formatting functions

computeMoves :: Instance -> String -> IMove -> String -> String -> (String, [String])Source

printSolutionLine Source

Arguments

:: List	The node list
-> List	The instance list
-> Int	Maximum node name length
-> Int	Maximum instance name length
-> Placement	The current placement
-> Int	The index of the placement in the solution
-> (String, [String])

Converts a placement to string format.

involvedNodes Source

Arguments

:: List	Instance list, used for retrieving the instance from its index; note that this must be the original instance list, so that we can retrieve the old nodes
-> Placement	The placement we're investigating, containing the new nodes and instance index
-> [Ndx]	Resulting list of node indices

Return the instance and involved nodes in an instance move.

Note that the output list length can vary, and is not required nor guaranteed to be of any specific length.

mergeJobs :: ([JobSet], [Ndx]) -> MoveJob -> ([JobSet], [Ndx])Source

splitJobs :: [MoveJob] -> [JobSet]Source

Break a list of moves into independent groups. Note that this will reverse the order of jobs.

formatJob :: Int -> Int -> (Int, MoveJob) -> [String]Source

formatCmds :: [JobSet] -> StringSource

Given a list of commands, prefix them with gnt-instance and also beautify the display a little.

printNodes :: List -> [String] -> StringSource

Print the node list.

printInsts :: List -> List -> StringSource

Print the instance list.

printStats :: String -> List -> StringSource

Shows statistics for a given node list.

iMoveToJob Source

Arguments

:: List	The node list; only used for node names, so any version is good (before or after the operation)
-> List	The instance list; also used for names only
-> Idx	The index of the instance being moved
-> IMove	The actual move to be described
-> [OpCode]	The list of opcodes equivalent to the given move

Convert a placement into a list of OpCodes (basically a job).

Node group functions

instanceGroup :: List -> Instance -> Result Gdx Source

Computes the group of an instance.

instancePriGroup :: List -> Instance -> Gdx Source

findSplitInstances :: List -> List -> [Instance]Source

Compute the list of badly allocated instances (split across node groups).

splitCluster :: List -> List -> [(Gdx, (List, List))]Source

Splits a cluster into the component node groups.

nodesToEvacuate :: List -> EvacMode -> [Idx] -> IntSetSource