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Knative Serving API Specification

Authors: argent@google.com, dangerd@google.com

Status

APPROVED

Created

2019-06-24

Last Updated

2019-11-04

Version

1.0.1

Abstract

The Knative serving platform provides common abstractions for managing request-driven, short-lived, stateless compute resources in the style of common FaaS and PaaS offerings. This document describes the structure, lifecycle and management of Knative resources in the context of the Kubernetes Resource Model. An understanding of the Kubernetes API interface and the capabilities of Kubernetes Custom Resources is assumed. The Knative Serving API surface aims to support the following additional constraints beyond the general Kubernetes model:

  • Client-side orchestration should not be required for common operations such as deployment, rollback, or simple imperative updates ("change environment variable X").
  • Both declarative (aka GitOps) and imperative (command-driven) management of resources should be usable, though not on the same resources at the same time. (I.e. one application may use a checked-in configuration which is automatically pushed, while a different application may be pushed and updated by hand with the authoritative state living on the server.)
  • Developers can effectively use the Knative Serving stack without needing to engage beyond the core Knative resource model. Conversely, platform operators may restrict developers (e.g. via RBAC) to only be able to operate on the core Knative Serving resources, and may provide additional abstractions to manage platform-specific settings.
  • The Knative Serving API may be deployed in a single-tenant or multi-tenant environment; it is assumed that developers may not have access to multiple namespaces or any cluster-level resources.

This document does not define the runtime contract (see this document) nor prescribe specific implementations of supporting services such as access control, observability, or resource management.

This document makes reference in a few places to different profiles for Knative Serving installations. A profile in this context is a set of operations, resources, and fields that are accessible to a developer interacting with a Knative installation. Currently, only a single (minimal) profile for Knative Serving is defined, but additional profiles may be defined in the future to standardize advanced functionality. A minimal profile is one that implements all of the "MUST", "MUST NOT", and "REQUIRED" conditions of this document.

Background

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in RFC 2119.

There is no formal specification of the Kubernetes API and Resource Model. This document assumes Kubernetes 1.13 behavior; this behavior will typically be supported by many future Kubernetes versions. Additionally, this document may reference specific core Kubernetes resources; these references may be illustrative (i.e. an implementation on Kubernetes) or descriptive (i.e. this Kubernetes resource MUST be exposed). References to these core Kubernetes resources will be annotated as either illustrative or descriptive.

This document considers two users of a given Knative Serving environment, and is particularly concerned with the expectations of developers (and language and tooling developers, by extension) deploying applications to the environment.

  • Developers write code which is packaged into a container which is run on the Knative Serving cluster.
    • Language and tooling developers typically write tools used by developers to package code into containers. As such, they are concerned that tooling which wraps developer code to produce resources which match the Knative API contract.
  • Operators (also known as platform providers) provision the compute resources and manage the software configuration of Knative Serving and the underlying abstractions (for example: Linux, Kubernetes, Istio, etc).

RBAC Profile

In order to validate the controls described in Resource Overview, the following Kubernetes RBAC profile may be applied in a Kubernetes cluster. This Kubernetes RBAC is an illustrative example of the minimal profile rather than a requirement. This Role should be sufficient to develop, deploy, and manage a set of serving applications within a single namespace. Knative Conformance tests against "MUST", "MUST NOT", and "REQUIRED" conditions are expected to pass when using this profile:

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: knative-developer
rules:
  - apiGroups: ["serving.knative.dev"]
    resources: ["services"]
    verbs: ["get", "list", "create", "update", "delete"]
  - apiGroups: ["serving.knative.dev"]
    resources: ["configurations", "routes", "revisions"]
    verbs: ["get", "list"]

Resource Overview

The Knative Serving API provides a set of Kubernetes Custom Resources to manage stateless request-triggered (i.e. on-demand) autoscaled containers. Knative Serving assumes the use of HTTP (including HTTP/2 and layered protocols such as gRPC) as a request transport. In addition to low-level scaling and routing objects, Knative Serving provides a high-level Service object to reduce the cognitive overhead for application developers – the Service object should provide sufficient controls to cover most of application deployment scenarios (by frequency).

Service

The Knative Service represents an instantiation of a single serverless container environment (e.g. a microservice) over time. As such, a Service includes both a network address by which the Service may be reached as well as the application code and configuration needed to run the Service. The following table details which operations must be made available to a developer accessing a Knative Service using a minimal profile:

API Operation Developer Access Requirements
Create (POST) REQUIRED
Patch (PATCH)^ RECOMMENDED
Replace (PUT) REQUIRED
Delete (DELETE) REQUIRED
Read (GET) REQUIRED
List (GET) REQUIRED
Watch (GET) OPTIONAL
DeleteCollection (DELETE) OPTIONAL

^ Kubernetes only allows JSON merge patch for CRD types. It is recommended that if allowed, at least JSON Merge patch be made available. JSON Merge Patch Spec (RFC 7386)

Revision

The Knative Revision represents a stateless, autoscaling snapshot-in-time of application code and configuration. Revisions enable progressive rollout and rollback of application changes by changing the HTTP routing between Service names and Revision instances. As such, Revisions are generally immutable, except where they may reference mutable core Kubernetes resources such as ConfigMaps and Secrets. Revisions can also be mutated by changes in Revision defaults. Changes to defaults that mutate Revisions are generally syntactic and not semantic.

Developers MUST NOT be able to create Revisions or update Revision spec directly; Revisions MUST be created in response to updates to a Configuration spec. It is RECOMMENDED that developers are able to force the deletion of Revisions to both handle the possibility of leaked resources as well as for removal of known-bad Revisions to avoid future errors in managing the service.

The following table details which operations must be made available to a developer accessing a Knative Revision using a minimal profile:

API Operation Developer Access Requirements
Create (POST) FORBIDDEN
Patch (PATCH)^ OPTIONAL (spec disallowed)
Replace (PUT) OPTIONAL (spec changes disallowed)
Delete (DELETE) RECOMMENDED
Read (GET) REQUIRED
List (GET) REQUIRED
Watch (GET) OPTIONAL
DeleteCollection (DELETE) OPTIONAL

^ Kubernetes only allows JSON merge patch for CRD types. It is recommended that if allowed, at least JSON Merge patch be made available. JSON Merge Patch Spec (RFC 7386)

Route

The Knative Route represents the current HTTP request routing state against a set of Revisions. To enable progressive rollout of serverless applications, a Route supports percentage-based request distribution across multiple application code and configuration states (Revisions).

Routes which are owned (controlled) by a Service SHOULD NOT be updated by developers; any changes will be reset by the Service controller.

The table below details which operations must be made available to a developer accessing a Knative Route using a minimal profile. For any non-minimal profile, the POST, PUT, or DELETE operations MUST be enabled as a group. This ensures that the developer has the ability to control the complete lifecycle of the object from create through deletion.

API Operation Developer Access Requirements
Create (POST) OPTIONAL
Patch (PATCH)^ OPTIONAL
Replace (PUT) OPTIONAL
Delete (DELETE) OPTIONAL
Read (GET) REQUIRED
List (GET) REQUIRED
Watch (GET) OPTIONAL
DeleteCollection (DELETE) OPTIONAL

^ Kubernetes only allows JSON merge patch for CRD types. It is recommended that if allowed, at least JSON Merge patch be made available. JSON Merge Patch Spec (RFC 7386)

Configuration

The Knative Configuration represents the desired future state (after deployments complete) of a single autoscaled container application and configuration. The Configuration provides a template for creating Revisions as the desired state of the application changes.

Configurations which are owned (controlled) by a Service SHOULD NOT be updated by developers; any changes will be reset by the Service controller. These changes MAY still generate side effects such as the creation of additional Revisions.

The table below details which operations must be made available to a developer accessing a Knative Configuration using a minimal profile. For any advanced profile, the POST, PUT, or DELETE operations MUST be enabled as a group. This ensures that the developer has the ability to control the complete lifecycle of the object from create through deletion.

API Operation Developer Access Requirements
Create (POST) OPTIONAL
Patch (PATCH)^ OPTIONAL
Replace (PUT) OPTIONAL
Delete (DELETE) OPTIONAL
Read (GET) REQUIRED
List (GET) REQUIRED
Watch (GET) OPTIONAL
DeleteCollection (DELETE) OPTIONAL

^ Kubernetes only allows JSON merge patch for CRD types. It is recommended that if allowed, at least JSON Merge patch be made available. JSON Merge Patch Spec (RFC 7386)

Error Signalling

The Knative API uses the Kubernetes Conditions convention to communicate errors and problems to the user. Each user-visible resource described in Resource Overview MUST have a conditions field in status, which must be a list of Condition objects of the following form (note that the actual API object types may be named FooCondition to allow better code generation and disambiguation between similar fields in the same apiGroup):

Field Type Description Default Value
type string The category of the condition, as a short, CamelCase word or phrase.

This is the primary key of the Conditions list when viewed as a map.

REQUIRED – No default
status Enum:
  • "True"
  • "False"
  • "Unknown"
The last measured status of this condition. "Unknown"
reason string One-word CamelCase reason for the condition's last transition. ""
message string Human-readable sentence describing the last transition. ""
severity Enum:
  • ""
  • "Warning"
  • "Info"
If present, represents the severity of the condition. An empty severity represents a severity level of "Error". ""
lastTransitionTime Timestamp Last update time for this condition. "" – may be unset

Additionally, the resource's status.conditions field MUST be managed as follows to enable clients (particularly user interfaces) to present useful diagnostic and error message to the user. In the following section, conditions are referred to by their type (aka the string value of the type field on the Condition).

  1. Each resource MUST have either a Ready condition (for ongoing systems) or Succeeded condition (for resources that run to completion) with severity="", which MUST use the True, False, and Unknown status values as follows:

    1. False MUST indicate a failure condition.
    2. Unknown SHOULD indicate that reconciliation is not yet complete and success or failure is not yet determined.
    3. True SHOULD indicate that the application is fully reconciled and operating correctly.

    Unknown and True are specified as SHOULD rather than MUST requirements because there may be errors which prevent serving which cannot be determined by the API stack (e.g. DNS record configuration in certain environments). Implementations are expected to treat these as "MUST" for factors within the control of the implementation.

  2. For non-Ready conditions, any conditions with severity="" (aka "Error conditions") must be aggregated into the "Ready" condition as follows:

    1. If the condition is False, Ready MUST be False.
    2. If the condition is Unknown, Ready MUST be False or Unknown.
    3. If the condition is True, Ready may be any of True, False, or Unknown.

    Implementations MAY choose to report that Ready is False or Unknown even if all Error conditions report a status of True (i.e. there may be additional hidden implementation conditions which feed into the Ready condition which are not reported.)

  3. Non-Ready conditions with non-error severity MAY be surfaced by the implementation. Examples of Warning or Info conditions could include: missing health check definitions, scale-to-zero status, or non-fatal capacity limits.

Conditions type names should be chosen to describe positive conditions where True means that the condition has been satisfied. Some conditions may be transient (for example, ResourcesAllocated might change between True and False as an application scales to and from zero). It is RECOMMENDED that transient conditions be indicated with a severity="Info".

Resource Lifecycle

Revisions are created by updates to the spec of Configuration resources, which own the Revision lifecycle. Similarly, Service resources create and own (control) Routes and Configurations. In some profiles, Route and Configuration may be directly created without creating an owning Service; this is considered an advanced environment, as it exposes more concepts and higher-cardinality relationships to the developer.

This section describes the rules by which the different resources interact. The general Kubernetes model is that of continuous reconciliation across eventually-consistent resources.

Ownership

In several of the following sections, resources are said to "own" another resource. Ownership indicates that the owned resource is being managed by the owning resource and MUST be recorded using an OwnerReference in metadata.ownerReferences on the owned resource with controller set to True and uid set to the UID of the owning resource.

If the owning resource determines an ownership conflict and does not hold an OwnerReference, the owning resource SHOULD NOT modify the resource, and SHOULD signal the conflict with an error Condition.

Deleting an owning resource MUST trigger deletion of all owned resources; this deletion MAY be immediate or eventually consistent. This process can be implemented using Kubernetes cascading deletion.

Service

When a Service is created, it MUST create and own a Configuration and Route with the same name as the Service. Updates to spec, metadata.labels, and metadata.annotations of the Service MUST be copied to the appropriate Configuration or Route, as follows:

  • metadata changes MUST be copied to both Configuration and Route.
  • In addition, the serving.knative.dev/service label on the Route and Configuration MUST be set to the name of the Service.
  • Additional labels and annotations on the Configuration and Route not specified above MUST be removed.
  • See the documentation of spec in the detailed resource fields section for the mapping of specific spec fields to the corresponding fields in Configuration and Route.

Similarly, the Service MUST update its status fields based on the corresponding status of its owned Route and Configuration. The Service MUST include conditions of ConfigurationsReady and RoutesReady in addition to the generic Ready condition; other conditions MAY also be present.

Configuration

When a Configuration is created or its spec updated, the following steps MUST be taken to create a new Revision (on creation, the previous state for all fields is an empty value):

  • If the spec.template field has changed from the previous state, a new owned Revision MUST be created. If the Revision name is not provided by the user through the spec.template.metadata.name field, it MUST be system generated. The system generated name should be treated opaquely as no semantics are defined. The values of spec.template.metadata and spec.template.spec MUST be copied to the newly created Revision. If the Revision cannot be created, the Configuration MUST signal that the Configuration is not Ready.
  • metadata.labels and metadata.annotations from the Configuration MUST NOT be copied to the newly-created Revision.

Configuration MUST track the status of owned Revisions in order of creation, and report the name of the most recently created Revision in status.latestCreatedRevisionName and the name of the most recently created Revision where the Ready Condition is True in status.latestReadyRevisionName. These fields MAY be used by client software and Route objects to determine the status of the Configuration and the best target Revision for requests.

Revision

A Revision is automatically scaled by the underlying infrastructure; a Revision with no referencing Routes MAY be automatically scaled to zero instances and backing resources collected. Additionally, Revisions which are older than the oldest live Revision (referenced by at least one Route or latest for the Configuration) MAY be automatically deleted by the system.

Route

Route does not directly own any Knative resources, but may refer to multiple Revisions which will receive incoming requests either directly or through a reference to a Configuration's status.latestReadyRevisionName field. In these cases, the Route MAY use a serving.knative.dev/route label to indicate that a Configuration or Revision is currently referenced by the Route. This label or other mechanisms MAY be used to prevent user deletion of Revisions referenced by a Route.

Request Routing

Knative uses fractional host-based HTTP routing to deliver requests to autoscaled instances. Knative Routes specify request routing from HTTP virtual hosts (Host-header based routing) to fractional assignments to Revisions. The following semantics apply to Knative request routing:

  • Each HTTP/1.1 request MUST be treated as a separate "request" using the following semantics.
  • If supported by the Knative installation, each HTTP/2 stream MUST be treated as a separate "request" using the following semantics. Note that this maps naturally for HTTP requests over HTTP/2, but is also well-defined for other applications like gRPC.
  • DNS Hostnames allocated to Routes MUST be unique.
  • DNS Hostnames allocated to Routes SHOULD resolve. Wildcard DNS records associated with a domain assigned to the namespace are the RECOMMENDED implementation.
  • Requests to a specific Host MUST be dispatched to Revision instances in accordance with the weights specified in the Route, even if the number of container instances per Revision does not match the weights specified in the Route.
  • When a selected Revision does not have available instances, the routing infrastructure MUST hold (delay) requests until an available instance is ready, scheduling a new container instance if needed. This is sometimes referred to as a "cold start".
  • Requests which cause a new container instance to be created ("cold start") SHOULD be sent to the initially selected Revision, rather than to a different Revision.
  • Multiple simultaneous or subsequent requests from a single client (even over the same TCP connection) MAY be dispatched to different instances or different Revisions (traffic routing MUST NOT be "sticky" in a way which violates the weight distributions). Developers SHOULD NOT assume that subsequent requests from the same client will reach the same application instance.

Detailed Resources – v1beta1

The following schema defines a set of REQUIRED or RECOMMENDED resource fields on the Knative resource types. Whether a field is REQUIRED or RECOMMENDED is denoted in the "Schema Requirement" column. Additional spec and status fields MAY be provided by particular implementations, however it is expected that most extension will be accomplished via the metadata.labels and metadata.annotations fields, as Knative implementations MAY validate supplied resources against these fields and refuse resources which specify unknown fields. Knative implementations MUST NOT require spec fields outside this implementation; to do so would break interoperability between such implementations and implementations which implement validation of field names.

Service

Metadata:

Standard Kubernetes meta.v1/ObjectMeta resource.

Service labels and annotations MUST be copied to the labels and annotations on the owned Configuration and Route. Additionally, the owned Configuration and Route MUST have the serving.knative.dev/service label set to the name of the Service.

Spec:

Field Name Field Type Description Schema Requirement
template RevisionTemplateSpec
(Required)
A template for the current desired application state. Changes to template will cause a new Revision to be created as defined in the lifecycle section. The contents of the Service's RevisionTemplateSpec is used to create a corresponding Configuration. REQUIRED
traffic []TrafficTarget
(Optional)
Traffic specifies how to distribute traffic over a collection of Revisions belonging to the Service. If traffic is empty or not provided, defaults to 100% traffic to the latest Ready Revision. The contents of the Service's TrafficTarget is used to create a corresponding Route. REQUIRED

Status:

FieldName Field Type Description Schema Requirement
conditions See Error Signalling Used for signalling errors, see link. Conditions of type Ready MUST be present. Conditions of type ConfigurationsReady and RoutesReady MAY be present. REQUIRED
observedGeneration int The latest metadata.generation that the reconciler has observed. If observedGeneration is updated, conditions MUST be updated with current status in the same transaction. REQUIRED
url string (url) A URL which may be used to reach the application, copied from the owned Route. The URL MUST contain the scheme (i.e. "http://", etc.). REQUIRED
address An implementation of the

Addressable contract (an object with a url string).

A duck-typed interface for loading the delivery address of the destination, copied from the owned Route. The URL provided in address MAY only be internally-routable. REQUIRED
traffic []TrafficTarget Detailed current traffic split routing information. REQUIRED
latestReadyRevisionName string The most recently created Revision with where the Ready Condition is True. REQUIRED
latestCreatedRevisionName string The most recently created Revision. REQUIRED

Configuration

Metadata:

Standard Kubernetes meta.v1/ObjectMeta resource.

Configuration labels and annotations MUST NOT be copied to the labels and annotations on newly-created Revisions. Configuration metadata MUST NOT be continuously copied to existing Revisions, which should remain immutable after creation. Additionally, the newly-created Revision MUST have the serving.knative.dev/configuration label set to the name of the Configuration. The Revision MUST also have the serving.knative.dev/configurationGeneration label set to the Configuration's metadata.generation from which this Revision was created.

Spec:

FieldName Field Type Description Schema Requirement
template

RevisionTemplateSpec
(Required)

A template for the current desired application state. Changes to template will cause a new Revision to be created

as defined in the lifecycle section.

REQUIRED

Status:

FieldName Field Type Description Schema Requirement
conditions

See Error Signalling

Used for signalling errors, see link. Condition of type Ready MUST be present. REQUIRED
observedGeneration int The latest metadata.generation that the reconciler has attempted. If observedGeneration is updated, conditions MUST be updated with current status in the same transaction. REQUIRED
latestReadyRevisionName string The most recently created Revision with where the Ready Condition is True. REQUIRED
latestCreatedRevisionName string The most recently created Revision. REQUIRED

Route

Metadata:

Standard Kubernetes meta.v1/ObjectMeta resource.

Spec:

FieldName Field Type Description Schema Requirement
traffic []TrafficTarget
(Optional)
Traffic specifies how to distribute traffic over a collection of Revisions belonging to the Service. If traffic is empty or not provided, defaults to 100% traffic to the latest Ready Revision. REQUIRED

Status:

FieldName Field Type Description Schema Requirement
conditions

See Error Signalling

Used for signalling errors, see link. Conditions of types Ready MUST be present. `AllTrafficAssigned`, `IngressReady`, and `CertificateProvisioned` MAY be present. REQUIRED
observedGeneration int The latest `metadata.generation` that the reconciler has observed. If observedGeneration is updated, conditions MUST be updated with current status in the same transaction. REQUIRED
url string (url) A URL which may be used to reach the application. The URL MUST contain the scheme (i.e. "http://", etc.). REQUIRED
address An implementation of the Addressable contract (an object with a url string). A duck-typed interface for loading the delivery address of the destination. The URL provided in address MAY only be internally-routable. REQUIRED
traffic []TrafficTarget Detailed current traffic split routing information. REQUIRED

Revision

Metadata:

Standard Kubernetes meta.v1/ObjectMeta resource.

Spec:

FieldName Field Type Description Schema Requirement
containers []Container
(Required)
Min: 1
Max: 1
Specifies the parameters used to execute each container instance corresponding to this Revision. REQUIRED
volumes []Volume
(Optional)
A list of Volumes to make available to containers[0]. RECOMMENDED
timeoutSeconds int
(Optional)
The maximum duration in seconds that the request routing layer will wait for a request delivered to a container to progress (send network traffic). If unspecified, a system default will be provided. REQUIRED
containerConcurrency int
(Optional)
Default: 0
The maximum number of concurrent requests being handled by a single instance of containers[0]. The default value is 0, which means that the system decides.

See

Request Routing for more details on what constitutes a request.

REQUIRED
serviceAccountName string
(Optional)
The name of a Service Account which containers[0] should be run as. The Service Account should be used to provide access and authorization to the container. RECOMMENDED
imagePullSecrets []LocalObjectReference
(Optional)
The list of secrets for pulling images from private repositories. RECOMMENDED

Status:

FieldName Field Type Description Schema Requirement
conditions

See Error Signalling

Used for signalling errors, see link. Conditions of type Ready MUST be present. Conditions of type Active, ContainerHealthy, ResourcesAvailable MAY be present. REQUIRED
logUrl string (url) A URL which may be used to retrieve logs specific to this Revision. The destination MAY require authentication and/or use a format (such as a web UI) which requires additional configuration. There is no further standardization of this URL or the targeted endpoint. REQUIRED
imageDigest string The resolved image digest for the requested Container. This MAY be omitted by the implementation. RECOMMENDED

Detailed Resource Types - v1beta1

Although container, volumes, and types that they reference are based upon core Kubernetes objects, there are additional limitations applied to ensure that created containers can statelessly autoscale. The set of fields that have been determined to be compatible with statelessly scaling are detailed below. Restrictions to the values of the field are noted in the Description column.

TrafficTarget

FieldName Field Type Description Schema Requirement
revisionName string

(Optional)

A specific revision to which to send this portion of traffic. This is mutually exclusive with configurationName. REQUIRED
configurationName string

(Optional)

ConfigurationName of a configuration to whose latest Revision we will send this portion of traffic. Tracks latestReadyRevisionName for the Configuration. This field is never set in status, only in spec. This is mutually exclusive with revisionName. This field is disallowed when used in

ServiceSpec.

REQUIRED
latestRevision bool

(Optional)

latestRevision may be optionally provided to indicate that the latest ready Revision of the Configuration should be used for this traffic target. When provided latestRevision MUST be true if revisionName is empty, and it MUST be false when revisionName is non-empty. REQUIRED
tag string

(Optional)

Tag is optionally used to expose a dedicated URL for referencing this target exclusively. The dedicated URL MUST include in it the string provided by tag. REQUIRED
percent int
(Required)
Min: 0
Max: 100
The

percentage of requests which should be allocated from the main Route domain name to the specified revisionName or configurationName.

All percent values in traffic MUST sum to 100.

REQUIRED
url string The URL at which the tag endpoint is reachable. It MUST not be taken as input, and is only provided on Status. REQUIRED

RevisionTemplateSpec

FieldName Field Type Description Schema Requirement
metadata

RevisionMetadata

The requested metadata for the Revision. REQUIRED
spec

RevisionSpec

The requested spec for the Revision. REQUIRED

Container

FieldName Field Type Description Schema Requirement
args []string

(Optional)

As specified in Kubernetes core/v1.Container. REQUIRED
command []string

(Optional)

As specified in Kubernetes core/v1.Container. REQUIRED
env []EnvVar

(Optional)

As specified in Kubernetes core/v1.Container. REQUIRED
envFrom []EnvFromSource

(Optional)

As specified in Kubernetes core/v1.Container. RECOMMENDED
image string

(Required)

As specified in Kubernetes core/v1.Container. REQUIRED
imagePullPolicy string

(Optional)

As specified in Kubernetes core/v1.Container. However, Knative resolves the image to a digest. The pull policy will be applied against the digest of the resolved image and not the image tag. RECOMMENDED
livenessProbe Probe

(Optional)

As specified in Kubernetes core/v1.Container. RECOMMENDED
name string

(Optional)

As specified in Kubernetes core/v1.Container. RECOMMENDED
ports []ContainerPort
(Optional)
Min: 0
Max: 1
Only a single port may be specified. The port must be named as described in the runtime contract. REQUIRED
readinessProbe Probe
(Optional)
As specified in Kubernetes core/v1.Container. RECOMMENDED
resources ResourceRequirements
(Optional)
As specified in Kubernetes core/v1.Container. REQUIRED
securityContext SecurityContext
(Optional)
In securityContext, only runAsUser MAY be set. RECOMMENDED
terminationMessagePath string
(Optional)
As specified in Kubernetes core/v1.Container. RECOMMENDED
terminationMessagePolicy string
(Optional)
As specified in Kubernetes core/v1.Container. RECOMMENDED
volumeMounts []VolumeMount
(Optional)
volumeMounts MUST correspond to a volume and specify an absolute mount path which does not shadow the runtime contract directories. REQUIRED, if volumes is supported.
workingDir string
(Optional)
As specified in Kubernetes core/v1.Container. REQUIRED

EnvVar

FieldName Field Type Description Schema Requirement
name string
(Required)
As specified in Kubernetes core/v1.EnvVar REQUIRED
value string
(Optional)
As specified in Kubernetes core/v1.EnvVar. Must have one of value or valueFrom. REQUIRED
valueFrom EnvVarSource
(Optional)
As specified in Kubernetes core/v1.EnvVar. Must have one of value or valueFrom. RECOMMENDED

EnvVarSource

FieldName Field Type Description Schema Requirement
configMapKeyRef ConfigMapKeySelector
(Optional)
As specified in Kubernetes core/v1.EnvVarSource. Must have one of configMapKeyRef or secretKeyRef. REQUIRED, if valueFrom is supported.
secretKeyRef SecretKeySelector
(Optional)
As specified in Kubernetes core/v1.EnvVarSource. Must have one of configMapKeyRef or secretKeyRef. RECOMMENDED

ConfigMapKeySelector

FieldName Field Type Description Schema Requirement
key string As specified in Kubernetes core/v1.ConfigMapKeySelector. REQUIRED, if configMapKeyRef is supported
name string As specified in Kubernetes core/v1.ConfigMapKeySelector. REQUIRED, if configMapKeyRef is supported
optional boolean As specified in Kubernetes core/v1.ConfigMapKeySelector. REQUIRED, if configMapKeyRef is supported

SecretKeySelector

FieldName Field Type Description Schema Requirement
key string As specified in Kubernetes core/v1.SecretKeySelector. REQUIRED, if secretKeyRef is supported
name string As specified in Kubernetes core/v1.SecretKeySelector. REQUIRED, if secretKeyRef is supported
optional boolean As specified in Kubernetes core/v1.SecretKeySelector. REQUIRED, if secretKeyRef is supported

Probe

FieldName Field Type Description Schema Requirement
exec

ExecAction

As specified in Kubernetes core/v1.Probe. RECOMMENDED
failureThreshold string As specified in Kubernetes core/v1.Probe. REQUIRED, if livenessProbe or readinessProbe is supported
httpGet

HTTPGetAction

As specified in Kubernetes core/v1.Probe. REQUIRED, if livenessProbe or readinessProbe is supported
initialDelaySeconds int As specified in Kubernetes core/v1.Probe. REQUIRED, if livenessProbe or readinessProbe is supported
successThreshold int As specified in Kubernetes core/v1.Probe. REQUIRED, if livenessProbe or readinessProbe is supported
tcpSocket

TCPSocketAction

As specified in Kubernetes core/v1.Probe. REQUIRED, if livenessProbe or readinessProbe is supported
timeoutSeconds int As specified in Kubernetes core/v1.Probe. REQUIRED, if livenessProbe or readinessProbe is supported

EnvFromSource

FieldName Field Type Description Schema Requirement
configMapRef

ConfigMapEnvSource

As specified in Kubernetes core/v1.EnvFromSource. REQUIRED, if envFrom is supported
prefix string As specified in Kubernetes core/v1.EnvFromSource. REQUIRED, if envFrom is supported
secretRef

SecretEnvSource

As specified in Kubernetes core/v1.EnvFromSource. RECOMMENDED

ExecAction

FieldName Field Type Description Schema Requirement
command []string
(Required)
As specified in Kubernetes core/v1.ExecAction. REQUIRED, if exec is supported

HTTPGetAction

FieldName Field Type Description Schema Requirement
host string As specified in Kubernetes core/v1.HTTPGetAction. REQUIRED, if livenessProbe or readinessProbe is supported
httpHeaders

HTTPHeader

As specified in Kubernetes core/v1.HTTPGetAction. REQUIRED, if livenessProbe or readinessProbe is supported
path string As specified in Kubernetes core/v1.HTTPGetAction. REQUIRED, if livenessProbe or readinessProbe is supported
scheme string As specified in Kubernetes core/v1.HTTPGetAction. REQUIRED, if livenessProbe or readinessProbe is supported

TCPSocketAction

FieldName Field Type Description Schema Requirement
host string As specified in Kubernetes core/v1.TCPSocketAction. REQUIRED, if livenessProbe or readinessProbe is supported

HTTPHeader

FieldName Field Type Description Schema Requirement
name string As specified in Kubernetes core/v1.HTTPHeader. REQUIRED, if livenessProbe or readinessProbe is supported
value string As specified in Kubernetes core/v1.HTTPHeader. REQUIRED, if livenessProbe or readinessProbe is supported

ContainerPort

FieldName Field Type Description Schema Requirement
name string
(Optional)
Must be one of "http1" or "h2c" (if supported). Defaults to "http1". REQUIRED
containerPort int The selected port for which Knative will direct traffic to the user container. REQUIRED
protocol string
(Optional)
If specified must be TCP. Defaults to TCP. REQUIRED

ConfigMapEnvSource

FieldName Field Type Description Schema Requirement
name string As specified in Kubernetes core/v1.ConfigMapEnvSource. REQUIRED, if envFrom is supported
optional boolean As specified in Kubernetes core/v1.ConfigMapEnvSource. REQUIRED, if envFrom is supported

SecretEnvSource

FieldName Field Type Description Schema Requirement
name string As specified in Kubernetes core/v1.SecretEnvSource. REQUIRED, if secretRef is supported
optional boolean As specified in Kubernetes core/v1.SecretEnvSource. REQUIRED, if secretRef is supported

ResourceRequirements

FieldName Field Type Description Schema Requirement
limits object Must support at least cpu and memory. See Kubernetes. REQUIRED
requests object Must support at least cpu and memory. See Kubernetes. REQUIRED

SecurityContext

FieldName Field Type Description Schema Requirement
runAsUser int As specified in Kubernetes core/v1.SecurityContext REQUIRED, if securityContext is supported.

VolumeMount

FieldName Field Type Description Schema Requirement
mountPath string As specified in Kubernetes core/v1.VolumeMount. REQUIRED, if volumes is supported.
name string As specified in Kubernetes core/v1.VolumeMount. REQUIRED, if volumes is supported.
subPath string As specified in Kubernetes core/v1.VolumeMount. REQUIRED, if volumes is supported.
readOnly bool Must be true. Defaults to true. REQUIRED, if volumes is supported.

Volume

FieldName Field Type Description Schema Requirement
configMap

ConfigMapVolumeSource

As specified in Kubernetes core/v1.Volume. REQUIRED, if volumes is supported.
secret

SecretVolumeSource

As specified in Kubernetes core/v1.Volume. RECOMMENDED
projected

ProjectedVolumeSource

As specified in Kubernetes core/v1.Volume. RECOMMENDED

ConfigMapVolumeSource

FieldName Field Type Description Schema Requirement
defaultMode int As specified in Kubernetes core/v1.ConfigMapVolumeSource. REQUIRED, if volumes is supported.
items []KeyToPath As specified in Kubernetes core/v1.ConfigMapVolumeSource. REQUIRED, if volumes is supported.
name string As specified in Kubernetes core/v1.ConfigMapVolumeSource. REQUIRED, if volumes is supported.
optional bool As specified in Kubernetes core/v1.ConfigMapVolumeSource. REQUIRED, if volumes is supported.

SecretVolumeSource

FieldName Field Type Description Schema Requirement
defaultMode int As specified in Kubernetes core/v1.SecretVolumeSource. REQUIRED, if secret is supported.
items []KeyToPath As specified in Kubernetes core/v1.SecretVolumeSource. REQUIRED, if secret is supported.
secretName string As specified in Kubernetes core/v1.SecretVolumeSource. REQUIRED, if secret is supported.
optional bool As specified in Kubernetes core/v1.SecretVolumeSource. REQUIRED, if secret is supported.

ProjectedVolumeSource

FieldName Field Type Description Schema Requirement
defaultMode int As specified in Kubernetes core/v1.ProjectedVolumeSource. REQUIRED, if projected is supported.
sources []VolumeProjection As specified in Kubernetes core/v1.ProjectedVolumeSource. REQUIRED, if projected is supported.

KeyToPath

FieldName Field Type Description Schema Requirement
key string As specified in Kubernetes core/v1.KeyToPath. REQUIRED, if volumes is supported.
mode int As specified in Kubernetes core/v1.KeyToPath. REQUIRED, if volumes is supported.
path string As specified in Kubernetes core/v1.KeyToPath. REQUIRED, if volumes is supported.

VolumeProjection

FieldName Field Type Description Schema Requirement
configMap

ConfigMapProjection

As specified in Kubernetes core/v1.VolumeProjection. REQUIRED, if projected is supported.
secret

SecretProjection

As specified in Kubernetes core/v1.VolumeProjection. REQUIRED, if projected is supported.

ConfigMapProjection

FieldName Field Type Description Schema Requirement
items []KeyToPath As specified in Kubernetes core/v1.ConfigMapProjection. REQUIRED, if projected is supported.
secret string As specified in Kubernetes core/v1.ConfigMapProjection. REQUIRED, if projected is supported.
optional boolean As specified in Kubernetes core/v1.ConfigMapProjection. REQUIRED, if projected is supported.

SecretProjection

FieldName Field Type Description Schema Requirement
items []KeyToPath As specified in Kubernetes core/v1.SecretProjection. REQUIRED, if projected is supported.
name string As specified in Kubernetes core/v1.SecretProjection. REQUIRED, if projected is supported.
optional boolean As specified in Kubernetes core/v1.SecretProjection. REQUIRED, if projected is supported.

Addressable (Interface)

FieldName Field Type Description Schema Requirement
url string (apis.URL) A generic mechanism for a custom resource definition to indicate a destination for message delivery. REQUIRED

LocalObjectReference

FieldName Field Type Description Schema Requirement
name string As specified in Kubernetes core/v1.LocalObjectReference. REQUIRED, if imagePullSecrets is supported.
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