SLO (v1)

SLO represents a target value or range for a service level measured by an SLI.

Examples

Basic

apiVersion: openslo/v1
kind: SLO
metadata:
  name: main-page
  displayName: Main page availability
spec:
  description: Our main page should be available always
  service: web-shop
  indicator:
    metadata:
      name: response-code
      displayName: Response codes of requests to main page
    spec:
      ratioMetric:
        good:
          metricSource:
            type: Any # Here put any service that holds information you need.
            spec: # Fields necessary to query service for the data.
              query: Any # 'query' is just an example field.
        total:
          metricSource:
            type: Any # Here put any service that holds information you need.
            spec: # Fields necessary to query service for the data.
              query: Any # 'query' is just an example field.
  timeWindow:
   - duration: 2w
     isRolling: true
  budgetingMethod: RatioTimeslices
  objectives:
    - displayName: Good
      timeSliceWindow: 1m
      target: 0.99

Properties

apiVersion

string required

Version represents a version of the OpenSLO specification.

Allowed values: openslo/v1

Validation rules

Rule
property is required
must be equal to openslo/v1

kind

string required

Kind represents all the object kinds defined by OpenSLO specification. Keep in mind not all specification versions support every Kind.

Allowed values: SLO

Validation rules

Rule
property is required
must be equal to SLO

metadata

struct required reference

See the metadata definition in the overview.

Validation rules

Rule
property is required

spec

struct required

SLOSpec defines the service association, indicator placement, budgeting method, evaluation window, objectives, and alert policies of an SLO.

Validation rules

Rule	Applies when
property is required
indicator or indicatorRef fields must either be defined on the spec level (standard SLOs) or on the spec.objectives[*] level (composite SLOs)
exactly one of indicator and indicatorRef must be set	indicator or indicatorRef is set

spec.description

string

Description summarizes the SLO.

Validation rules

Rule
property is optional
length must be less than or equal to 1050

spec.service

string required

Service names the associated service. Consumers define how to resolve the name to a Service.

Validation rules

Rule
property is required

spec.indicator

struct reference

Indicator defines a standard SLO's SLI inline. Composite SLOs place indicators on individual Objectives.

Use the metadata and spec properties from the SLI definition. The inline form omits apiVersion and kind.

Validation rules

Rule	Applies when
property is optional	indicator or indicatorRef is set

spec.indicatorRef

string

IndicatorRef names an existing SLI for a standard SLO. Composite SLOs place indicator references on individual Objectives.

Validation rules

Rule	Applies when	Details	Examples
property is optional	indicator or indicatorRef is set
length must be between 1 and 63	indicator or indicatorRef is set
string must match regular expression: ^[a-z0-9]([-a-z0-9]*[a-z0-9])?$	indicator or indicatorRef is set	an RFC-1123 compliant label name must consist of lower case alphanumeric characters or -, and must start and end with an alphanumeric character	my-name 123-abc

spec.budgetingMethod

string required

BudgetingMethod applies the selected error-budget calculation to every objective.

SLOBudgetingMethod identifies how an SLO aggregates SLI results for objective and error-budget evaluation. An objective's error-budget fraction is 1 minus SLOObjective.Target. Its error-budget percentage is 100 minus SLOObjective.TargetPercent. Occurrences uses the ratio of good events to total events. Timeslices counts slices that meet SLOObjective.TimeSliceTarget. RatioTimeslices averages success ratios across slices. Composite calculation rules depend on the method, as the constant comments describe.

Allowed values: Occurrences, Timeslices, RatioTimeslices

Validation rules

Rule
property is required
must be one of: Occurrences, Timeslices, RatioTimeslices

spec.timeWindow

[]struct

TimeWindow defines the period over which the SLO is evaluated.

Validation rules

Rule
length must be between 1 and 1

spec.timeWindow[*]

struct

SLOTimeWindow defines one rolling or calendar-aligned evaluation window.

Validation rules

Rule
calendar must be set when isRolling is false and cannot be set when isRolling is true

spec.timeWindow[*].duration

string required

Duration is the length of the evaluation window.

DurationShorthand represents a duration as an integer and a case-sensitive DurationShorthandUnit, such as "1m" or "10d". A zero value encodes as empty text.

Validation rules

Rule
property is required

Validation of value components

These rules apply to parts of this value.

Component: unit

Possible values: m, h, d, w, M, Q, Y

Rule
property is required
must be one of: m, h, d, w, M, Q, Y

Component: value

Rule
must be greater than or equal to 0

spec.timeWindow[*].isRolling

bool

IsRolling selects a rolling window when true and a calendar-aligned window when false.

spec.timeWindow[*].calendar

struct

Calendar defines the alignment of a calendar window.

SLOCalendar anchors a calendar-aligned SLOTimeWindow in a time zone.

Validation rules

Rule
property is optional

spec.timeWindow[*].calendar.startTime

string

StartTime anchors the first calendar window.

Validation rules

Rule	Details
string must be a valid date and time in 2006-01-02 15:04:05 format	date and time format follows Go's time layout, see https://pkg.go.dev/time#Layout for more details

spec.timeWindow[*].calendar.timeZone

string

TimeZone controls the interpretation of StartTime and later boundaries.

Validation rules

Rule	Examples
string must be a valid IANA Time Zone Database code	UTC America/New_York Europe/Warsaw

spec.objectives

[]struct

Objectives contains the SLO's target definitions.

spec.objectives[*]

struct

SLOObjective defines a success target and, when applicable, a threshold comparison or composite-specific indicator. For example, Target 0.995 and TargetPercent 99.5 both express a 99.5 percent target.

Validation rules

Rule	Applies when
exactly one of target and targetPercent must be set
exactly one of indicator and indicatorRef must be set	is composite SLO and indicator or indicatorRef is set

spec.objectives[*].displayName

string

DisplayName is the objective's human-readable name.

spec.objectives[*].op

string conditionally required

Operator compares threshold-metric samples with Value.

Operator identifies a comparison applied to a metric value.

Possible values: gt, lt, gte, lte

The applicable values depend on the conditions in the validation rules below.

Validation rules

Rule	Applies when
property is forbidden	indicator.spec.ratioMetric is set
property is required	indicator.spec.thresholdMetric is set
must be one of: gt, lt, gte, lte	indicator.spec.thresholdMetric is set

spec.objectives[*].value

float64 conditionally required

Value sets the threshold for metric sample comparisons. It is distinct from the success target expressed by Target or TargetPercent.

Validation rules

Rule	Applies when
property is forbidden	indicator.spec.ratioMetric is set
property is required	indicator.spec.thresholdMetric is set

spec.objectives[*].target

float64

Target expresses the success target as a fraction.

Validation rules

Rule
property is optional
must be greater than or equal to 0
must be less than 1

spec.objectives[*].targetPercent

float64

TargetPercent expresses the success target as a percentage.

Validation rules

Rule
property is optional
must be greater than or equal to 0
must be less than 100

spec.objectives[*].timeSliceTarget

float64 conditionally required

TimeSliceTarget classifies a slice as good when BudgetingMethod is SLOBudgetingMethodTimeslices.

Validation rules

Rule	Applies when
property is required	budgetingMethod is Timeslices
must be greater than 0	budgetingMethod is Timeslices
must be less than or equal to 1	budgetingMethod is Timeslices

spec.objectives[*].timeSliceWindow

string conditionally required

TimeSliceWindow sets the slice size and query interval. It applies to SLOBudgetingMethodTimeslices and SLOBudgetingMethodRatioTimeslices. This Go model supports DurationShorthand only. OpenSLO also permits a number, which it interprets as minutes.

DurationShorthand represents a duration as an integer and a case-sensitive DurationShorthandUnit, such as "1m" or "10d". A zero value encodes as empty text.

Validation rules

Rule	Applies when
property is required	budgetingMethod is Timeslices
property is required	budgetingMethod is RatioTimeslices

Validation of value components

These rules apply to parts of this value.

Component: unit

Possible values: M, Q, Y, d, h, m, w

Rule	Applies when
property is required	budgetingMethod is Timeslices
must be one of: m, h, d, w, M, Q, Y	budgetingMethod is Timeslices
property is required	budgetingMethod is RatioTimeslices
must be one of: m, h, d, w, M, Q, Y	budgetingMethod is RatioTimeslices

Component: value

Rule	Applies when
must be greater than or equal to 0	budgetingMethod is Timeslices
must be greater than or equal to 0	budgetingMethod is RatioTimeslices

spec.objectives[*].indicator

struct reference

Indicator defines this objective's SLI inline for a composite SLO.

Use the metadata and spec properties from the SLI definition. The inline form omits apiVersion and kind.

Validation rules

Rule	Applies when
property is optional	is composite SLO and indicator or indicatorRef is set

spec.objectives[*].indicatorRef

string

IndicatorRef names this objective's SLI for a composite SLO.

Validation rules

Rule	Applies when	Details	Examples
property is optional	is composite SLO and indicator or indicatorRef is set
length must be between 1 and 63	is composite SLO and indicator or indicatorRef is set
string must match regular expression: ^[a-z0-9]([-a-z0-9]*[a-z0-9])?$	is composite SLO and indicator or indicatorRef is set	an RFC-1123 compliant label name must consist of lower case alphanumeric characters or -, and must start and end with an alphanumeric character	my-name 123-abc

spec.objectives[*].compositeWeight

float64

CompositeWeight scales this objective's contribution to a composite SLO. OpenSLO defaults it to 1, but this SDK preserves an omitted value as nil.

Validation rules

Rule	Applies when
property is optional	is composite SLO
must be greater than 0	is composite SLO

spec.alertPolicies

[]struct

AlertPolicies contains inline alert policies or references to existing AlertPolicy objects.

spec.alertPolicies[*]

struct

SLOAlertPolicy supplies an inline or referenced alert policy to an SLO.

Validation rules

Rule
exactly one of alertPolicyRef and spec must be set
property is optional

spec.alertPolicies[*].kind

string required

Kind represents all the object kinds defined by OpenSLO specification. Keep in mind not all specification versions support every Kind.

Allowed values: AlertPolicy

Validation rules

Rule
property is required
must be equal to AlertPolicy

spec.alertPolicies[*].metadata

struct required reference

See the metadata definition in the overview.

Validation rules

Rule
property is required

spec.alertPolicies[*].spec

struct required reference

See the AlertPolicy specification.

Validation rules

Rule
property is required

spec.alertPolicies[*].alertPolicyRef

string required

AlertPolicyRef matches the Metadata.Name of an existing AlertPolicy.

Validation rules

Rule	Details	Examples
property is required
length must be between 1 and 63
string must match regular expression: ^[a-z0-9]([-a-z0-9]*[a-z0-9])?$	an RFC-1123 compliant label name must consist of lower case alphanumeric characters or -, and must start and end with an alphanumeric character	my-name 123-abc