scheduler

package
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 Go to latest Published: Oct 6, 2015 License: MPL-2.0 Imports: 9 Imported by: 0

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Constants

This section is empty.

Variables

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var BuiltinSchedulers = map[string]Factory{
	"service": NewServiceScheduler,
	"batch":   NewBatchScheduler,
}

BuiltinSchedulers contains the built in registered schedulers which are available

Functions

This section is empty.

Types

type BinPackIterator 

type BinPackIterator struct {
	// contains filtered or unexported fields
}

BinPackIterator is a RankIterator that scores potential options based on a bin-packing algorithm.

func NewBinPackIterator 

func NewBinPackIterator(ctx Context, source RankIterator, evict bool, priority int) *BinPackIterator

NewBinPackIterator returns a BinPackIterator which tries to fit tasks potentially evicting other tasks based on a given priority.

func (*BinPackIterator) Next 

func (iter *BinPackIterator) Next() *RankedNode

func (*BinPackIterator) Reset 

func (iter *BinPackIterator) Reset()

func (*BinPackIterator) SetPriority 

func (iter *BinPackIterator) SetPriority(p int)

func (*BinPackIterator) SetTasks 

func (iter *BinPackIterator) SetTasks(tasks []*structs.Task)

type ConstraintIterator 

type ConstraintIterator struct {
	// contains filtered or unexported fields
}

ConstraintIterator is a FeasibleIterator which returns nodes that match a given set of constraints. This is used to filter on job, task group, and task constraints.

func NewConstraintIterator 

func NewConstraintIterator(ctx Context, source FeasibleIterator, constraints []*structs.Constraint) *ConstraintIterator

NewConstraintIterator creates a ConstraintIterator from a source and set of constraints

func (*ConstraintIterator) Next 

func (iter *ConstraintIterator) Next() *structs.Node

func (*ConstraintIterator) Reset 

func (iter *ConstraintIterator) Reset()

func (*ConstraintIterator) SetConstraints 

func (iter *ConstraintIterator) SetConstraints(c []*structs.Constraint)

type Context 

type Context interface {
	// State is used to inspect the current global state
	State() State

	// Plan returns the current plan
	Plan() *structs.Plan

	// Logger provides a way to log
	Logger() *log.Logger

	// Metrics returns the current metrics
	Metrics() *structs.AllocMetric

	// Reset is invoked after making a placement
	Reset()

	// ProposedAllocs returns the proposed allocations for a node
	// which is the existing allocations, removing evictions, and
	// adding any planned placements.
	ProposedAllocs(nodeID string) ([]*structs.Allocation, error)
}

Context is used to track contextual information used for placement

type DriverIterator 

type DriverIterator struct {
	// contains filtered or unexported fields
}

DriverIterator is a FeasibleIterator which returns nodes that have the drivers necessary to scheduler a task group.

func NewDriverIterator 

func NewDriverIterator(ctx Context, source FeasibleIterator, drivers map[string]struct{}) *DriverIterator

NewDriverIterator creates a DriverIterator from a source and set of drivers

func (*DriverIterator) Next 

func (iter *DriverIterator) Next() *structs.Node

func (*DriverIterator) Reset 

func (iter *DriverIterator) Reset()

func (*DriverIterator) SetDrivers 

func (iter *DriverIterator) SetDrivers(d map[string]struct{})

type EvalContext 

type EvalContext struct {
	// contains filtered or unexported fields
}

EvalContext is a Context used during an Evaluation

func NewEvalContext 

func NewEvalContext(s State, p *structs.Plan, log *log.Logger) *EvalContext

NewEvalContext constructs a new EvalContext

func (*EvalContext) Logger 

func (e *EvalContext) Logger() *log.Logger

func (*EvalContext) Metrics 

func (e *EvalContext) Metrics() *structs.AllocMetric

func (*EvalContext) Plan 

func (e *EvalContext) Plan() *structs.Plan

func (*EvalContext) ProposedAllocs 

func (e *EvalContext) ProposedAllocs(nodeID string) ([]*structs.Allocation, error)

func (*EvalContext) Reset 

func (e *EvalContext) Reset()

func (*EvalContext) SetState 

func (e *EvalContext) SetState(s State)

func (*EvalContext) State 

func (e *EvalContext) State() State

type Factory 

type Factory func(*log.Logger, State, Planner) Scheduler

Factory is used to instantiate a new Scheduler

type FeasibleIterator 

type FeasibleIterator interface {
	// Next yields a feasible node or nil if exhausted
	Next() *structs.Node

	// Reset is invoked when an allocation has been placed
	// to reset any stale state.
	Reset()
}

FeasibleIterator is used to iteratively yield nodes that match feasibility constraints. The iterators may manage some state for performance optimizations.

type FeasibleRankIterator 

type FeasibleRankIterator struct {
	// contains filtered or unexported fields
}

FeasibleRankIterator is used to consume from a FeasibleIterator and return an unranked node with base ranking.

func NewFeasibleRankIterator 

func NewFeasibleRankIterator(ctx Context, source FeasibleIterator) *FeasibleRankIterator

NewFeasibleRankIterator is used to return a new FeasibleRankIterator from a FeasibleIterator source.

func (*FeasibleRankIterator) Next 

func (iter *FeasibleRankIterator) Next() *RankedNode

func (*FeasibleRankIterator) Reset 

func (iter *FeasibleRankIterator) Reset()

type GenericScheduler 

type GenericScheduler struct {
	// contains filtered or unexported fields
}

GenericScheduler is used for 'service' and 'batch' type jobs. This scheduler is designed for long-lived services, and as such spends more time attemping to make a high quality placement. This is the primary scheduler for most workloads. It also supports a 'batch' mode to optimize for fast decision making at the cost of quality.

func (*GenericScheduler) Process 

func (s *GenericScheduler) Process(eval *structs.Evaluation) error

Process is used to handle a single evaluation

type GenericStack 

type GenericStack struct {
	// contains filtered or unexported fields
}

GenericStack is the Stack used for the Generic scheduler. It is designed to make better placement decisions at the cost of performance.

func NewGenericStack 

func NewGenericStack(batch bool, ctx Context, baseNodes []*structs.Node) *GenericStack

NewGenericStack constructs a stack used for selecting service placements

func (*GenericStack) Select 

func (s *GenericStack) Select(tg *structs.TaskGroup) (*RankedNode, *structs.Resources)

func (*GenericStack) SetJob 

func (s *GenericStack) SetJob(job *structs.Job)

func (*GenericStack) SetNodes 

func (s *GenericStack) SetNodes(baseNodes []*structs.Node)

type JobAntiAffinityIterator 

type JobAntiAffinityIterator struct {
	// contains filtered or unexported fields
}

JobAntiAffinityIterator is used to apply an anti-affinity to allocating along side other allocations from this job. This is used to help distribute load across the cluster.

func NewJobAntiAffinityIterator 

func NewJobAntiAffinityIterator(ctx Context, source RankIterator, penalty float64, jobID string) *JobAntiAffinityIterator

NewJobAntiAffinityIterator is used to create a JobAntiAffinityIterator that applies the given penalty for co-placement with allocs from this job.

func (*JobAntiAffinityIterator) Next 

func (iter *JobAntiAffinityIterator) Next() *RankedNode

func (*JobAntiAffinityIterator) Reset 

func (iter *JobAntiAffinityIterator) Reset()

func (*JobAntiAffinityIterator) SetJob 

func (iter *JobAntiAffinityIterator) SetJob(jobID string)

type LimitIterator 

type LimitIterator struct {
	// contains filtered or unexported fields
}

LimitIterator is a RankIterator used to limit the number of options that are returned before we artifically end the stream.

func NewLimitIterator 

func NewLimitIterator(ctx Context, source RankIterator, limit int) *LimitIterator

NewLimitIterator is returns a LimitIterator with a fixed limit of returned options

func (*LimitIterator) Next 

func (iter *LimitIterator) Next() *RankedNode

func (*LimitIterator) Reset 

func (iter *LimitIterator) Reset()

func (*LimitIterator) SetLimit 

func (iter *LimitIterator) SetLimit(limit int)

type MaxScoreIterator 

type MaxScoreIterator struct {
	// contains filtered or unexported fields
}

MaxScoreIterator is a RankIterator used to return only a single result of the item with the highest score. This iterator will consume all of the possible inputs and only returns the highest ranking result.

func NewMaxScoreIterator 

func NewMaxScoreIterator(ctx Context, source RankIterator) *MaxScoreIterator

MaxScoreIterator returns a MaxScoreIterator over the given source

func (*MaxScoreIterator) Next 

func (iter *MaxScoreIterator) Next() *RankedNode

func (*MaxScoreIterator) Reset 

func (iter *MaxScoreIterator) Reset()

type Planner 

type Planner interface {
	// SubmitPlan is used to submit a plan for consideration.
	// This will return a PlanResult or an error. It is possible
	// that this will result in a state refresh as well.
	SubmitPlan(*structs.Plan) (*structs.PlanResult, State, error)

	// UpdateEval is used to update an evaluation. This should update
	// a copy of the input evaluation since that should be immutable.
	UpdateEval(*structs.Evaluation) error

	// CreateEval is used to create an evaluation. This should set the
	// PreviousEval to that of the current evaluation.
	CreateEval(*structs.Evaluation) error
}

Planner interface is used to submit a task allocation plan.

type RankIterator 

type RankIterator interface {
	// Next yields a ranked option or nil if exhausted
	Next() *RankedNode

	// Reset is invoked when an allocation has been placed
	// to reset any stale state.
	Reset()
}

RankFeasibleIterator is used to iteratively yield nodes along with ranking metadata. The iterators may manage some state for performance optimizations.

type RankedNode 

type RankedNode struct {
	Node          *structs.Node
	Score         float64
	TaskResources map[string]*structs.Resources

	// Allocs is used to cache the proposed allocations on the
	// node. This can be shared between iterators that require it.
	Proposed []*structs.Allocation
}

Rank is used to provide a score and various ranking metadata along with a node when iterating. This state can be modified as various rank methods are applied.

func (*RankedNode) GoString 

func (r *RankedNode) GoString() string

func (*RankedNode) ProposedAllocs 

func (r *RankedNode) ProposedAllocs(ctx Context) ([]*structs.Allocation, error)

func (*RankedNode) SetTaskResources 

func (r *RankedNode) SetTaskResources(task *structs.Task,
	resource *structs.Resources)

type Scheduler 

type Scheduler interface {
	// Process is used to handle a new evaluation. The scheduler is free to
	// apply any logic necessary to make the task placements. The state and
	// planner will be provided prior to any invocations of process.
	Process(*structs.Evaluation) error
}

Scheduler is the top level instance for a scheduler. A scheduler is meant to only encapsulate business logic, pushing the various plumbing into Nomad itself. They are invoked to process a single evaluation at a time. The evaluation may result in task allocations which are computed optimistically, as there are many concurrent evaluations being processed. The task allocations are submitted as a plan, and the current leader will coordinate the commmits to prevent oversubscription or improper allocations based on stale state.

func NewBatchScheduler 

func NewBatchScheduler(logger *log.Logger, state State, planner Planner) Scheduler

NewBatchScheduler is a factory function to instantiate a new batch scheduler

func NewScheduler 

func NewScheduler(name string, logger *log.Logger, state State, planner Planner) (Scheduler, error)

NewScheduler is used to instantiate and return a new scheduler given the scheduler name, initial state, and planner.

func NewServiceScheduler 

func NewServiceScheduler(logger *log.Logger, state State, planner Planner) Scheduler

NewServiceScheduler is a factory function to instantiate a new service scheduler

type SetStatusError 

type SetStatusError struct {
	Err        error
	EvalStatus string
}

SetStatusError is used to set the status of the evaluation to the given error

func (*SetStatusError) Error 

func (s *SetStatusError) Error() string

type Stack 

type Stack interface {
	// SetNodes is used to set the base set of potential nodes
	SetNodes([]*structs.Node)

	// SetTaskGroup is used to set the job for selection
	SetJob(job *structs.Job)

	// Select is used to select a node for the task group
	Select(tg *structs.TaskGroup) (*RankedNode, *structs.Resources)
}

Stack is a chained collection of iterators. The stack is used to make placement decisions. Different schedulers may customize the stack they use to vary the way placements are made.

type State 

type State interface {
	// Nodes returns an iterator over all the nodes.
	// The type of each result is *structs.Node
	Nodes() (memdb.ResultIterator, error)

	// AllocsByJob returns the allocations by JobID
	AllocsByJob(jobID string) ([]*structs.Allocation, error)

	// AllocsByNode returns all the allocations by node
	AllocsByNode(node string) ([]*structs.Allocation, error)

	// GetNodeByID is used to lookup a node by ID
	NodeByID(nodeID string) (*structs.Node, error)

	// GetJobByID is used to lookup a job by ID
	JobByID(id string) (*structs.Job, error)
}

State is an immutable view of the global state. This allows schedulers to make intelligent decisions based on allocations of other schedulers and to enforce complex constraints that require more information than is available to a local state scheduler.

type StaticIterator 

type StaticIterator struct {
	// contains filtered or unexported fields
}

StaticIterator is a FeasibleIterator which returns nodes in a static order. This is used at the base of the iterator chain only for testing due to deterministic behavior.

func NewRandomIterator 

func NewRandomIterator(ctx Context, nodes []*structs.Node) *StaticIterator

NewRandomIterator constructs a static iterator from a list of nodes after applying the Fisher-Yates algorithm for a random shuffle. This is applied in-place

func NewStaticIterator 

func NewStaticIterator(ctx Context, nodes []*structs.Node) *StaticIterator

NewStaticIterator constructs a random iterator from a list of nodes

func (*StaticIterator) Next 

func (iter *StaticIterator) Next() *structs.Node

func (*StaticIterator) Reset 

func (iter *StaticIterator) Reset()

func (*StaticIterator) SetNodes 

func (iter *StaticIterator) SetNodes(nodes []*structs.Node)

type StaticRankIterator 

type StaticRankIterator struct {
	// contains filtered or unexported fields
}

StaticRankIterator is a RankIterator that returns a static set of results. This is largely only useful for testing.

func NewStaticRankIterator 

func NewStaticRankIterator(ctx Context, nodes []*RankedNode) *StaticRankIterator

NewStaticRankIterator returns a new static rank iterator over the given nodes

func (*StaticRankIterator) Next 

func (iter *StaticRankIterator) Next() *RankedNode

func (*StaticRankIterator) Reset 

func (iter *StaticRankIterator) Reset()

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