scheduler

package
v0.6.0-rc2 Latest Latest
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 Go to latest Published: Jul 21, 2017 License: MPL-2.0 Imports: 19 Imported by: 0

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Index

Constants

View Source 
const (
	AnnotationForcesCreate            = "forces create"
	AnnotationForcesDestroy           = "forces destroy"
	AnnotationForcesInplaceUpdate     = "forces in-place update"
	AnnotationForcesDestructiveUpdate = "forces create/destroy update"
)
View Source 
const (
	UpdateTypeIgnore            = "ignore"
	UpdateTypeCreate            = "create"
	UpdateTypeDestroy           = "destroy"
	UpdateTypeMigrate           = "migrate"
	UpdateTypeCanary            = "canary"
	UpdateTypeInplaceUpdate     = "in-place update"
	UpdateTypeDestructiveUpdate = "create/destroy update"
)

UpdateTypes denote the type of update to occur against the task group.

View Source 
const (
	// SchedulerVersion is the version of the scheduler. Changes to the
	// scheduler that are incompatible with prior schedulers will increment this
	// version. It is used to disallow dequeueing when the versions do not match
	// across the leader and the dequeueing scheduler.
	SchedulerVersion uint16 = 1
)

Variables

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

BuiltinSchedulers contains the built in registered schedulers which are available

Functions

func Annotate added in v0.4.0 

func Annotate(diff *structs.JobDiff, annotations *structs.PlanAnnotations) error

Annotate takes the diff between the old and new version of a Job, the scheduler's plan annotations and will add annotations to the diff to aide human understanding of the plan.

Currently the things that are annotated are: * Task group changes will be annotated with:

  • Count up and count down changes
  • Update counts (creates, destroys, migrates, etc)

* Task changes will be annotated with:

  • forces create/destroy update
  • forces in-place update

func NewAllocReconciler added in v0.6.0 

func NewAllocReconciler(logger *log.Logger, allocUpdateFn allocUpdateType, batch bool,
	jobID string, job *structs.Job, deployment *structs.Deployment,
	existingAllocs []*structs.Allocation, taintedNodes map[string]*structs.Node) *allocReconciler

NewAllocReconciler creates a new reconciler that should be used to determine the changes required to bring the cluster state inline with the declared jobspec

func NewPropertySet added in v0.5.5 

func NewPropertySet(ctx Context, job *structs.Job) *propertySet

NewPropertySet returns a new property set used to guarantee unique property values for new allocation placements.

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) SetTaskGroup added in v0.5.0 

func (iter *BinPackIterator) SetTaskGroup(taskGroup *structs.TaskGroup)

type ComputedClassFeasibility added in v0.3.0 

type ComputedClassFeasibility byte
const (
	// EvalComputedClassUnknown is the initial state until the eligibility has
	// been explicitly marked to eligible/ineligible or escaped.
	EvalComputedClassUnknown ComputedClassFeasibility = iota

	// EvalComputedClassIneligible is used to mark the computed class as
	// ineligible for the evaluation.
	EvalComputedClassIneligible

	// EvalComputedClassIneligible is used to mark the computed class as
	// eligible for the evaluation.
	EvalComputedClassEligible

	// EvalComputedClassEscaped signals that computed class can not determine
	// eligibility because a constraint exists that is not captured by computed
	// node classes.
	EvalComputedClassEscaped
)

type ConstraintChecker added in v0.3.0 

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

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

func NewConstraintChecker added in v0.3.0 

func NewConstraintChecker(ctx Context, constraints []*structs.Constraint) *ConstraintChecker

NewConstraintChecker creates a ConstraintChecker for a set of constraints

func (*ConstraintChecker) Feasible added in v0.3.0 

func (c *ConstraintChecker) Feasible(option *structs.Node) bool

func (*ConstraintChecker) SetConstraints added in v0.3.0 

func (c *ConstraintChecker) SetConstraints(constraints []*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)

	// RegexpCache is a cache of regular expressions
	RegexpCache() map[string]*regexp.Regexp

	// ConstraintCache is a cache of version constraints
	ConstraintCache() map[string]version.Constraints

	// Eligibility returns a tracker for node eligibility in the context of the
	// eval.
	Eligibility() *EvalEligibility
}

Context is used to track contextual information used for placement

type DistinctHostsIterator added in v0.5.5 

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

DistinctHostsIterator is a FeasibleIterator which returns nodes that pass the distinct_hosts constraint. The constraint ensures that multiple allocations do not exist on the same node.

func NewDistinctHostsIterator added in v0.5.5 

func NewDistinctHostsIterator(ctx Context, source FeasibleIterator) *DistinctHostsIterator

NewDistinctHostsIterator creates a DistinctHostsIterator from a source.

func (*DistinctHostsIterator) Next added in v0.5.5 

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

func (*DistinctHostsIterator) Reset added in v0.5.5 

func (iter *DistinctHostsIterator) Reset()

func (*DistinctHostsIterator) SetJob added in v0.5.5 

func (iter *DistinctHostsIterator) SetJob(job *structs.Job)

func (*DistinctHostsIterator) SetTaskGroup added in v0.5.5 

func (iter *DistinctHostsIterator) SetTaskGroup(tg *structs.TaskGroup)

type DistinctPropertyIterator added in v0.5.5 

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

DistinctPropertyIterator is a FeasibleIterator which returns nodes that pass the distinct_property constraint. The constraint ensures that multiple allocations do not use the same value of the given property.

func NewDistinctPropertyIterator added in v0.5.5 

func NewDistinctPropertyIterator(ctx Context, source FeasibleIterator) *DistinctPropertyIterator

NewDistinctPropertyIterator creates a DistinctPropertyIterator from a source.

func (*DistinctPropertyIterator) Next added in v0.5.5 

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

func (*DistinctPropertyIterator) Reset added in v0.5.5 

func (iter *DistinctPropertyIterator) Reset()

func (*DistinctPropertyIterator) SetJob added in v0.5.5 

func (iter *DistinctPropertyIterator) SetJob(job *structs.Job)

func (*DistinctPropertyIterator) SetTaskGroup added in v0.5.5 

func (iter *DistinctPropertyIterator) SetTaskGroup(tg *structs.TaskGroup)

type DriverChecker added in v0.3.0 

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

DriverChecker is a FeasibilityChecker which returns whether a node has the drivers necessary to scheduler a task group.

func NewDriverChecker added in v0.3.0 

func NewDriverChecker(ctx Context, drivers map[string]struct{}) *DriverChecker

NewDriverChecker creates a DriverChecker from a set of drivers

func (*DriverChecker) Feasible added in v0.3.0 

func (c *DriverChecker) Feasible(option *structs.Node) bool

func (*DriverChecker) SetDrivers added in v0.3.0 

func (c *DriverChecker) SetDrivers(d map[string]struct{})

type EvalCache added in v0.2.0 

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

EvalCache is used to cache certain things during an evaluation

func (*EvalCache) ConstraintCache added in v0.2.0 

func (e *EvalCache) ConstraintCache() map[string]version.Constraints

func (*EvalCache) RegexpCache added in v0.2.0 

func (e *EvalCache) RegexpCache() map[string]*regexp.Regexp

type EvalContext 

type EvalContext struct {
	EvalCache
	// 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) Eligibility added in v0.3.0 

func (e *EvalContext) Eligibility() *EvalEligibility

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 EvalEligibility added in v0.3.0 

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

EvalEligibility tracks eligibility of nodes by computed node class over the course of an evaluation.

func NewEvalEligibility added in v0.3.0 

func NewEvalEligibility() *EvalEligibility

NewEvalEligibility returns an eligibility tracker for the context of an evaluation.

func (*EvalEligibility) GetClasses added in v0.3.0 

func (e *EvalEligibility) GetClasses() map[string]bool

GetClasses returns the tracked classes to their eligibility, across the job and task groups.

func (*EvalEligibility) HasEscaped added in v0.3.0 

func (e *EvalEligibility) HasEscaped() bool

HasEscaped returns whether any of the constraints in the passed job have escaped computed node classes.

func (*EvalEligibility) JobStatus added in v0.3.0 

func (e *EvalEligibility) JobStatus(class string) ComputedClassFeasibility

JobStatus returns the eligibility status of the job.

func (*EvalEligibility) SetJob added in v0.3.0 

func (e *EvalEligibility) SetJob(job *structs.Job)

SetJob takes the job being evaluated and calculates the escaped constraints at the job and task group level.

func (*EvalEligibility) SetJobEligibility added in v0.3.0 

func (e *EvalEligibility) SetJobEligibility(eligible bool, class string)

SetJobEligibility sets the eligibility status of the job for the computed node class.

func (*EvalEligibility) SetTaskGroupEligibility added in v0.3.0 

func (e *EvalEligibility) SetTaskGroupEligibility(eligible bool, tg, class string)

SetTaskGroupEligibility sets the eligibility status of the task group for the computed node class.

func (*EvalEligibility) TaskGroupStatus added in v0.3.0 

func (e *EvalEligibility) TaskGroupStatus(tg, class string) ComputedClassFeasibility

TaskGroupStatus returns the eligibility status of the task group.

type Factory 

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

Factory is used to instantiate a new Scheduler

type FeasibilityChecker added in v0.3.0 

type FeasibilityChecker interface {
	Feasible(*structs.Node) bool
}

FeasibilityChecker is used to check if a single node meets feasibility constraints.

type FeasibilityWrapper added in v0.3.0 

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

FeasibilityWrapper is a FeasibleIterator which wraps both job and task group FeasibilityCheckers in which feasibility checking can be skipped if the computed node class has previously been marked as eligible or ineligible.

func NewFeasibilityWrapper added in v0.3.0 

func NewFeasibilityWrapper(ctx Context, source FeasibleIterator,
	jobCheckers, tgCheckers []FeasibilityChecker) *FeasibilityWrapper

NewFeasibilityWrapper returns a FeasibleIterator based on the passed source and FeasibilityCheckers.

func (*FeasibilityWrapper) Next added in v0.3.0 

func (w *FeasibilityWrapper) Next() *structs.Node

Next returns an eligible node, only running the FeasibilityCheckers as needed based on the sources computed node class.

func (*FeasibilityWrapper) Reset added in v0.3.0 

func (w *FeasibilityWrapper) Reset()

func (*FeasibilityWrapper) SetTaskGroup added in v0.3.0 

func (w *FeasibilityWrapper) SetTaskGroup(tg string)

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) *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) SelectPreferringNodes added in v0.5.0 

func (s *GenericStack) SelectPreferringNodes(tg *structs.TaskGroup, nodes []*structs.Node) (*RankedNode, *structs.Resources)

SelectPreferredNode returns a node where an allocation of the task group can be placed, the node passed to it is preferred over the other available nodes

func (*GenericStack) SetJob 

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

func (*GenericStack) SetNodes 

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

type Harness added in v0.4.0 

type Harness struct {
	State *state.StateStore

	Planner Planner

	Plans        []*structs.Plan
	Evals        []*structs.Evaluation
	CreateEvals  []*structs.Evaluation
	ReblockEvals []*structs.Evaluation
	// contains filtered or unexported fields
}

Harness is a lightweight testing harness for schedulers. It manages a state store copy and provides the planner interface. It can be extended for various testing uses or for invoking the scheduler without side effects.

func NewHarness added in v0.4.0 

func NewHarness(t *testing.T) *Harness

NewHarness is used to make a new testing harness

func NewHarnessWithState added in v0.5.0 

func NewHarnessWithState(t *testing.T, state *state.StateStore) *Harness

NewHarnessWithState creates a new harness with the given state for testing purposes.

func (*Harness) AssertEvalStatus added in v0.4.0 

func (h *Harness) AssertEvalStatus(t *testing.T, state string)

func (*Harness) CreateEval added in v0.4.0 

func (h *Harness) CreateEval(eval *structs.Evaluation) error

func (*Harness) NextIndex added in v0.4.0 

func (h *Harness) NextIndex() uint64

NextIndex returns the next index

func (*Harness) Process added in v0.4.0 

func (h *Harness) Process(factory Factory, eval *structs.Evaluation) error

Process is used to process an evaluation given a factory function to create the scheduler

func (*Harness) ReblockEval added in v0.4.0 

func (h *Harness) ReblockEval(eval *structs.Evaluation) error

func (*Harness) Scheduler added in v0.4.0 

func (h *Harness) Scheduler(factory Factory) Scheduler

Scheduler is used to return a new scheduler from a snapshot of current state using the harness for planning.

func (*Harness) Snapshot added in v0.4.0 

func (h *Harness) Snapshot() State

Snapshot is used to snapshot the current state

func (*Harness) SubmitPlan added in v0.4.0 

func (h *Harness) SubmitPlan(plan *structs.Plan) (*structs.PlanResult, State, error)

SubmitPlan is used to handle plan submission

func (*Harness) UpdateEval added in v0.4.0 

func (h *Harness) UpdateEval(eval *structs.Evaluation) error

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 artificially 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

	// ReblockEval takes a blocked evaluation and re-inserts it into the blocked
	// evaluation tracker. This update occurs only in-memory on the leader. The
	// evaluation must exist in a blocked state prior to this being called such
	// that on leader changes, the evaluation will be reblocked properly.
	ReblockEval(*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 RejectPlan added in v0.4.0 

type RejectPlan struct {
	Harness *Harness
}

RejectPlan is used to always reject the entire plan and force a state refresh

func (*RejectPlan) CreateEval added in v0.4.0 

func (r *RejectPlan) CreateEval(*structs.Evaluation) error

func (*RejectPlan) ReblockEval added in v0.4.0 

func (r *RejectPlan) ReblockEval(*structs.Evaluation) error

func (*RejectPlan) SubmitPlan added in v0.4.0 

func (r *RejectPlan) SubmitPlan(*structs.Plan) (*structs.PlanResult, State, error)

func (*RejectPlan) UpdateEval added in v0.4.0 

func (r *RejectPlan) UpdateEval(eval *structs.Evaluation) error

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

func NewSystemScheduler added in v0.2.0 

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

NewSystemScheduler is a factory function to instantiate a new system 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(ws memdb.WatchSet) (memdb.ResultIterator, error)

	// AllocsByJob returns the allocations by JobID
	AllocsByJob(ws memdb.WatchSet, jobID string, all bool) ([]*structs.Allocation, error)

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

	// AllocsByNodeTerminal returns all the allocations by node filtering by terminal status
	AllocsByNodeTerminal(ws memdb.WatchSet, node string, terminal bool) ([]*structs.Allocation, error)

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

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

	// LatestDeploymentByJobID returns the latest deployment matching the given
	// job ID
	LatestDeploymentByJobID(ws memdb.WatchSet, jobID string) (*structs.Deployment, 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()

type SystemScheduler added in v0.2.0 

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

SystemScheduler is used for 'system' jobs. This scheduler is designed for services that should be run on every client.

func (*SystemScheduler) Process added in v0.2.0 

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

Process is used to handle a single evaluation.

type SystemStack added in v0.2.0 

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

SystemStack is the Stack used for the System scheduler. It is designed to attempt to make placements on all nodes.

func NewSystemStack added in v0.2.0 

func NewSystemStack(ctx Context) *SystemStack

NewSystemStack constructs a stack used for selecting service placements

func (*SystemStack) Select added in v0.2.0 

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

func (*SystemStack) SetJob added in v0.2.0 

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

func (*SystemStack) SetNodes added in v0.2.0 

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

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