sdk

package
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 Go to latest Published: Nov 23, 2020 License: MPL-2.0 Imports: 3 Imported by: 14

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Index

Constants

View Source 
const (
	ScalingPolicyTypeCluster    = "cluster"
	ScalingPolicyTypeHorizontal = "horizontal"
)
View Source 
const (
	// ScaleDirectionDown indicates the target should lower the number of running
	// instances of the resource.
	ScaleDirectionDown = iota - 1

	// ScaleDirectionNone indicates no scaling is required.
	ScaleDirectionNone

	// ScaleDirectionUp indicates the target should increase the number of
	// running instances of the resource.
	ScaleDirectionUp
)

The following constants are used to standardize the possible scaling directions for an Action. They are ordered from riskier to safest, with ScaleDirectionNone as the default and zero value.

View Source 
const (
	// TargetStatusMetaKeyLastEvent is an optional meta key that can be added
	// to the status return. The value represents the last scaling event of the
	// target as seen by the remote providers view point. This helps enforce
	// cooldown where out-of-band scaling activities have been triggered.
	TargetStatusMetaKeyLastEvent = "nomad_autoscaler.last_event"

	// TargetConfigKeyJob is the config key used within horizontal app scaling
	// to identify the Nomad job targeted for autoscaling.
	TargetConfigKeyJob = "Job"

	// TargetConfigKeyTaskGroup is the config key used within horizontal app
	// scaling to identify the Nomad job group targeted for autoscaling.
	TargetConfigKeyTaskGroup = "Group"

	// TargetConfigKeyClass is the config key used with horizontal cluster
	// scaling to identify Nomad clients as part of a pool of resources. This
	// pool of resources forms the scalable target.
	TargetConfigKeyClass = "node_class"

	// TargetConfigKeyDrainDeadline is the config key which defines the
	// override value to use when draining a Nomad client during the scale in
	// action of horizontal cluster scaling.
	TargetConfigKeyDrainDeadline = "node_drain_deadline"

	// TargetConfigKeyNodePurge is the config key which defines whether or not
	// Nomad clients are purged from Nomad once they have been terminated
	// within their provider.
	TargetConfigKeyNodePurge = "node_purge"
)
View Source 
const (

	// StrategyActionMetaValueDryRunCount is a special count value used when
	// performing dry-run scaling activities. The Autoscaler will never set a
	// count to a negative value during normal operation, so the agent is safe
	// to assume a count set to this value implies dry-run.
	StrategyActionMetaValueDryRunCount = -1
)

Variables

This section is empty.

Functions

This section is empty.

Types

type FileDecodePolicyCheckDoc 

type FileDecodePolicyCheckDoc struct {
	Name           string `hcl:"name,label"`
	Source         string `hcl:"source,optional"`
	Query          string `hcl:"query"`
	QueryWindow    time.Duration
	QueryWindowHCL string                 `hcl:"query_window,optional"`
	Strategy       *ScalingPolicyStrategy `hcl:"strategy,block"`
}

func (*FileDecodePolicyCheckDoc) Translate 

func (fdc *FileDecodePolicyCheckDoc) Translate(c *ScalingPolicyCheck)

Translate all values from the decoded policy check into our internal policy check object.

type FileDecodePolicyDoc 

type FileDecodePolicyDoc struct {
	Cooldown              time.Duration
	CooldownHCL           string `hcl:"cooldown,optional"`
	EvaluationInterval    time.Duration
	EvaluationIntervalHCL string                      `hcl:"evaluation_interval,optional"`
	Checks                []*FileDecodePolicyCheckDoc `hcl:"check,block"`
	Target                *ScalingPolicyTarget        `hcl:"target,block"`
}

type FileDecodeScalingPolicies 

type FileDecodeScalingPolicies struct {
	ScalingPolicies []*FileDecodeScalingPolicy `hcl:"scaling,block"`
}

type FileDecodeScalingPolicy 

type FileDecodeScalingPolicy struct {
	Name    string               `hcl:"name,label"`
	Enabled bool                 `hcl:"enabled,optional"`
	Type    string               `hcl:"type,optional"`
	Min     int64                `hcl:"min,optional"`
	Max     int64                `hcl:"max"`
	Doc     *FileDecodePolicyDoc `hcl:"policy,block"`
}

FileDecodeScalingPolicy is used as an intermediate step when decoding a policy from a file. It is needed because the internal Policy object is flattened when compared to the literal HCL version. Therefore we cannot translate into the internal struct but use this.

func (*FileDecodeScalingPolicy) Translate 

func (fpd *FileDecodeScalingPolicy) Translate() *ScalingPolicy

Translate all values from the decoded policy file into our internal policy object.

type ScaleDirection 

type ScaleDirection int8

ScaleDirection is an identifier used by strategy plugins to identify how the target should scale the named resource.

func (ScaleDirection) String 

func (d ScaleDirection) String() string

String satisfies the Stringer interface and returns as string representation of the scaling direction.

type ScalingAction 

type ScalingAction struct {

	// Count represents the desired count of the target resource. It should
	// always be zero or above, expect in the event of dry-run where it can use
	// the StrategyActionMetaValueDryRunCount value.
	Count int64

	// Reason is the top level string that provides a user friendly description
	// of why the strategy decided the action was required.
	Reason string

	// Error indicates whether the Reason string is an error condition. This
	// allows the Reason to be flexible in its use.
	Error bool

	// Direction is the scaling direction the strategy has decided should
	// happen. This is particularly helpful for non-Nomad target
	// implementations whose APIs dead with increment changes rather than
	// absolute counts.
	Direction ScaleDirection

	// Meta
	Meta map[string]interface{}
}

ScalingAction represents a strategy plugins intention to change the current target state. It includes all the required information to enact the change, along with useful meta information for operators and admins.

func PreemptScalingAction 

func PreemptScalingAction(a *ScalingAction, b *ScalingAction) *ScalingAction

PreemptScalingAction determines which ScalingAction should take precedence.

The result is based on the scaling direction and count. The order of precedence for the scaling directions is defined by the order in which they are declared in the above enum.

If the scaling direction is the same, the priority is given to the safest option, where safest is defined as lowest impact in the underlying infrastructure:

  • ScaleDirectionUp: Action with highest count
  • ScaleDirectionDown: Action with highest count

func (*ScalingAction) Canonicalize 

func (a *ScalingAction) Canonicalize()

Canonicalize ensures Action has proper default values.

func (*ScalingAction) CapCount 

func (a *ScalingAction) CapCount(min, max int64)

CapCount caps the value of Count so it remains within the specified limits. If Count is StrategyActionMetaValueDryRunCount this method has no effect.

func (*ScalingAction) SetDryRun 

func (a *ScalingAction) SetDryRun()

SetDryRun marks the Action to be executed in dry-run mode. Dry-run mode is indicated using Meta tags. A dry-run action doesn't modify the Target's count value.

type ScalingCheckEvaluation 

type ScalingCheckEvaluation struct {

	// Check is the individual ScalingPolicyCheck that this eval is concerned
	// with.
	Check *ScalingPolicyCheck

	// Metrics is the metric resulting from querying the APM.
	Metrics TimestampedMetrics

	// Action is the calculated desired state and is populated by strategy.Run.
	Action *ScalingAction
}

ScalingCheckEvaluation is the evaluation of an individual policy check. Each check eval within a ScalingEvaluation is performed concurrently and a single "winner" picked once all have returned.

type ScalingEvaluation 

type ScalingEvaluation struct {
	ID               string
	Policy           *ScalingPolicy
	TargetStatus     *TargetStatus
	CheckEvaluations []*ScalingCheckEvaluation
	CreateTime       time.Time
}

ScalingEvaluation forms an individual analysis undertaken by the autoscaler in order to determine the desired state of a target.

func NewScalingEvaluation 

func NewScalingEvaluation(p *ScalingPolicy, status *TargetStatus) *ScalingEvaluation

NewScalingEvaluation creates a new ScalingEvaluation based off the passed policy and status. It is responsible for hydrating all the fields to a basic level for safe usage throughout the scaling evaluation phase.

type ScalingPolicy 

type ScalingPolicy struct {

	// ID is a UUID which uniquely identifies this scaling policy. Depending on
	// the policy source this will be sourced in different manners.
	ID string

	// Type is the type of scaling this policy will perform.
	Type string

	// Priority controls the order in which a policy is picked for evaluation.
	Priority int

	// Min forms a lower bound at which the target should never be asked to
	// break. The autoscaler will actively adjust recommendations to ensure
	// this value is not violated.
	Min int64

	// Max forms an upper bound at which the target should never be asked to
	// exceed. The autoscaler will actively adjust recommendations to ensure
	// this value is not violated.
	Max int64

	// Enabled indicates whether the autoscaler should actively evaluate the
	// policy or not.
	Enabled bool

	// Cooldown is the time period after a scaling action if performed, during
	// which no policy evaluations will be started.
	Cooldown time.Duration

	// EvaluationInterval indicates the frequency at which the policy is
	// evaluated. A lower value means more frequent evaluation and can result
	// in a high rate of change in the target.
	EvaluationInterval time.Duration

	// Checks is an array of checks which will be triggered in parallel to
	// determine the desired state of the ScalingPolicyTarget.
	Checks []*ScalingPolicyCheck

	// Target identifies the scaling target which the autoscaler will interact
	// with to ensure it meets the desired state as determined by the Checks.
	Target *ScalingPolicyTarget
}

ScalingPolicy is the internal representation of a scaling document and encompasses all the required information for the autoscaler to perform scaling evaluations on a target.

type ScalingPolicyCheck 

type ScalingPolicyCheck struct {

	// Name is a human readable name for this check and allows operators to
	// create clearly identified policy checks.
	Name string

	// Source is the APM plugin that should be used to perform the query and
	// obtain the metric that will be used to perform a calculation.
	Source string

	// Query is run against the Source in order to receive a metric response.
	Query string

	// QueryWindow is used to define how further back in time to query for
	// metrics.
	QueryWindow time.Duration

	// Strategy is the ScalingPolicyStrategy to use when performing the
	// ScalingPolicyCheck evaluation.
	Strategy *ScalingPolicyStrategy
}

ScalingPolicyCheck is an individual check within a scaling policy.This check will be executed in isolation alongside other checks within the policy.

type ScalingPolicyStrategy 

type ScalingPolicyStrategy struct {

	// Name is the strategy that will be used to perform the desired state
	// calculation.
	Name string `hcl:"name,label"`

	// Config is the mapping of config values used by the strategy plugin. Each
	// plugin has a set of potentially uniquely supported keys.
	Config map[string]string `hcl:",remain"`
}

ScalingPolicyStrategy contains the plugin and configuration details for calculating the desired target state from the current state.

type ScalingPolicyTarget 

type ScalingPolicyTarget struct {

	// Name identifies the target plugin which can handle performing target
	// requests for this ScalingPolicy.
	Name string `hcl:"name,label"`

	// Config is the mapping of config values used by the target plugin. Each
	// plugin has a set of potentially uniquely supported keys.
	Config map[string]string `hcl:",remain"`
}

ScalingPolicyTarget identifies the target for which the ScalingPolicy as a whole is configured for.

func (*ScalingPolicyTarget) IsJobTaskGroupTarget 

func (t *ScalingPolicyTarget) IsJobTaskGroupTarget() bool

IsJobTaskGroupTarget identifies whether the ScalingPolicyTarget relates to a Nomad job group.

func (*ScalingPolicyTarget) IsNodePoolTarget 

func (t *ScalingPolicyTarget) IsNodePoolTarget() bool

IsNodePoolTarget identifies whether the ScalingPolicyTarget relates to Nomad client nodes and therefore horizontal cluster scaling.

type TargetStatus 

type TargetStatus struct {

	// Ready indicates whether the target is currently in a state where scaling
	// is permitted.
	Ready bool

	// Count is the current value of the target and thus performs the current
	// state basis when performing strategy calculations to identify the
	// desired state.
	Count int64

	// Meta is a mapping that provides additional information about the target
	// that can be used during the policy evaluation to ensure the correct
	// calculations and logic are applied to the target.
	Meta map[string]string
}

TargetStatus is the response object when performing the Status call of the target plugin interface. The response details key information about the current state of the target.

type TimeRange 

type TimeRange struct {
	From time.Time
	To   time.Time
}

TimeRange defines a range of time.

type TimestampedMetric 

type TimestampedMetric struct {
	Timestamp time.Time
	Value     float64
}

TimestampedMetric contains a single metric Value along with its associated Timestamp.

type TimestampedMetrics 

type TimestampedMetrics []TimestampedMetric

TimestampedMetrics is an array of timestamped metric values. This type is used so we can sort metrics based on the timestamp.

func (TimestampedMetrics) Len 

func (t TimestampedMetrics) Len() int

Len satisfies the Len function of the sort.Interface interface.

func (TimestampedMetrics) Less 

func (t TimestampedMetrics) Less(i, j int) bool

Less satisfies the Less function of the sort.Interface interface.

func (TimestampedMetrics) Swap 

func (t TimestampedMetrics) Swap(i, j int)

Swap satisfies the Swap function of the sort.Interface interface.

Source Files

View all Source files

Directories

Path Synopsis
helper
blocking
file
flag
nomad
ptr
scaleutils
uuid

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