Chapter 17. StatefulSet [apps/v1] Description StatefulSet represents a set of pods with consistent identities. Identities are defined as: - Network: A single stable DNS and hostname. - Storage: As many VolumeClaims as requested. The StatefulSet guarantees that a given network identity will always map to the same storage identity. Type object 17.1. Specification Property Type Description apiVersion string APIVersion defines the versioned schema of this representation of an object. Servers should convert recognized schemas to the latest internal value, and may reject unrecognized values. More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources kind string Kind is a string value representing the REST resource this object represents. Servers may infer this from the endpoint the client submits requests to. Cannot be updated. In CamelCase. More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds metadata ObjectMeta Standard object's metadata. More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#metadata spec object A StatefulSetSpec is the specification of a StatefulSet. status object StatefulSetStatus represents the current state of a StatefulSet. 17.1.1. .spec Description A StatefulSetSpec is the specification of a StatefulSet. Type object Required selector template serviceName Property Type Description minReadySeconds integer Minimum number of seconds for which a newly created pod should be ready without any of its container crashing for it to be considered available. Defaults to 0 (pod will be considered available as soon as it is ready) ordinals object StatefulSetOrdinals describes the policy used for replica ordinal assignment in this StatefulSet. persistentVolumeClaimRetentionPolicy object StatefulSetPersistentVolumeClaimRetentionPolicy describes the policy used for PVCs created from the StatefulSet VolumeClaimTemplates. podManagementPolicy string podManagementPolicy controls how pods are created during initial scale up, when replacing pods on nodes, or when scaling down. The default policy is OrderedReady , where pods are created in increasing order (pod-0, then pod-1, etc) and the controller will wait until each pod is ready before continuing. When scaling down, the pods are removed in the opposite order. The alternative policy is Parallel which will create pods in parallel to match the desired scale without waiting, and on scale down will delete all pods at once. Possible enum values: - "OrderedReady" will create pods in strictly increasing order on scale up and strictly decreasing order on scale down, progressing only when the pod is ready or terminated. At most one pod will be changed at any time. - "Parallel" will create and delete pods as soon as the stateful set replica count is changed, and will not wait for pods to be ready or complete termination. replicas integer replicas is the desired number of replicas of the given Template. These are replicas in the sense that they are instantiations of the same Template, but individual replicas also have a consistent identity. If unspecified, defaults to 1. revisionHistoryLimit integer revisionHistoryLimit is the maximum number of revisions that will be maintained in the StatefulSet's revision history. The revision history consists of all revisions not represented by a currently applied StatefulSetSpec version. The default value is 10. selector LabelSelector selector is a label query over pods that should match the replica count. It must match the pod template's labels. More info: https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#label-selectors serviceName string serviceName is the name of the service that governs this StatefulSet. This service must exist before the StatefulSet, and is responsible for the network identity of the set. Pods get DNS/hostnames that follow the pattern: pod-specific-string.serviceName.default.svc.cluster.local where "pod-specific-string" is managed by the StatefulSet controller. template PodTemplateSpec template is the object that describes the pod that will be created if insufficient replicas are detected. Each pod stamped out by the StatefulSet will fulfill this Template, but have a unique identity from the rest of the StatefulSet. Each pod will be named with the format <statefulsetname>-<podindex>. For example, a pod in a StatefulSet named "web" with index number "3" would be named "web-3". The only allowed template.spec.restartPolicy value is "Always". updateStrategy object StatefulSetUpdateStrategy indicates the strategy that the StatefulSet controller will use to perform updates. It includes any additional parameters necessary to perform the update for the indicated strategy. volumeClaimTemplates array (PersistentVolumeClaim) volumeClaimTemplates is a list of claims that pods are allowed to reference. The StatefulSet controller is responsible for mapping network identities to claims in a way that maintains the identity of a pod. Every claim in this list must have at least one matching (by name) volumeMount in one container in the template. A claim in this list takes precedence over any volumes in the template, with the same name. 17.1.2. .spec.ordinals Description StatefulSetOrdinals describes the policy used for replica ordinal assignment in this StatefulSet. Type object Property Type Description start integer start is the number representing the first replica's index. It may be used to number replicas from an alternate index (eg: 1-indexed) over the default 0-indexed names, or to orchestrate progressive movement of replicas from one StatefulSet to another. If set, replica indices will be in the range: [.spec.ordinals.start, .spec.ordinals.start + .spec.replicas). If unset, defaults to 0. Replica indices will be in the range: [0, .spec.replicas). 17.1.3. .spec.persistentVolumeClaimRetentionPolicy Description StatefulSetPersistentVolumeClaimRetentionPolicy describes the policy used for PVCs created from the StatefulSet VolumeClaimTemplates. Type object Property Type Description whenDeleted string WhenDeleted specifies what happens to PVCs created from StatefulSet VolumeClaimTemplates when the StatefulSet is deleted. The default policy of Retain causes PVCs to not be affected by StatefulSet deletion. The Delete policy causes those PVCs to be deleted. whenScaled string WhenScaled specifies what happens to PVCs created from StatefulSet VolumeClaimTemplates when the StatefulSet is scaled down. The default policy of Retain causes PVCs to not be affected by a scaledown. The Delete policy causes the associated PVCs for any excess pods above the replica count to be deleted. 17.1.4. .spec.updateStrategy Description StatefulSetUpdateStrategy indicates the strategy that the StatefulSet controller will use to perform updates. It includes any additional parameters necessary to perform the update for the indicated strategy. Type object Property Type Description rollingUpdate object RollingUpdateStatefulSetStrategy is used to communicate parameter for RollingUpdateStatefulSetStrategyType. type string Type indicates the type of the StatefulSetUpdateStrategy. Default is RollingUpdate. Possible enum values: - "OnDelete" triggers the legacy behavior. Version tracking and ordered rolling restarts are disabled. Pods are recreated from the StatefulSetSpec when they are manually deleted. When a scale operation is performed with this strategy,specification version indicated by the StatefulSet's currentRevision. - "RollingUpdate" indicates that update will be applied to all Pods in the StatefulSet with respect to the StatefulSet ordering constraints. When a scale operation is performed with this strategy, new Pods will be created from the specification version indicated by the StatefulSet's updateRevision. 17.1.5. .spec.updateStrategy.rollingUpdate Description RollingUpdateStatefulSetStrategy is used to communicate parameter for RollingUpdateStatefulSetStrategyType. Type object Property Type Description maxUnavailable IntOrString The maximum number of pods that can be unavailable during the update. Value can be an absolute number (ex: 5) or a percentage of desired pods (ex: 10%). Absolute number is calculated from percentage by rounding up. This can not be 0. Defaults to 1. This field is alpha-level and is only honored by servers that enable the MaxUnavailableStatefulSet feature. The field applies to all pods in the range 0 to Replicas-1. That means if there is any unavailable pod in the range 0 to Replicas-1, it will be counted towards MaxUnavailable. partition integer Partition indicates the ordinal at which the StatefulSet should be partitioned for updates. During a rolling update, all pods from ordinal Replicas-1 to Partition are updated. All pods from ordinal Partition-1 to 0 remain untouched. This is helpful in being able to do a canary based deployment. The default value is 0. 17.1.6. .status Description StatefulSetStatus represents the current state of a StatefulSet. Type object Required replicas Property Type Description availableReplicas integer Total number of available pods (ready for at least minReadySeconds) targeted by this statefulset. collisionCount integer collisionCount is the count of hash collisions for the StatefulSet. The StatefulSet controller uses this field as a collision avoidance mechanism when it needs to create the name for the newest ControllerRevision. conditions array Represents the latest available observations of a statefulset's current state. conditions[] object StatefulSetCondition describes the state of a statefulset at a certain point. currentReplicas integer currentReplicas is the number of Pods created by the StatefulSet controller from the StatefulSet version indicated by currentRevision. currentRevision string currentRevision, if not empty, indicates the version of the StatefulSet used to generate Pods in the sequence [0,currentReplicas). observedGeneration integer observedGeneration is the most recent generation observed for this StatefulSet. It corresponds to the StatefulSet's generation, which is updated on mutation by the API Server. readyReplicas integer readyReplicas is the number of pods created for this StatefulSet with a Ready Condition. replicas integer replicas is the number of Pods created by the StatefulSet controller. updateRevision string updateRevision, if not empty, indicates the version of the StatefulSet used to generate Pods in the sequence [replicas-updatedReplicas,replicas) updatedReplicas integer updatedReplicas is the number of Pods created by the StatefulSet controller from the StatefulSet version indicated by updateRevision. 17.1.7. .status.conditions Description Represents the latest available observations of a statefulset's current state. Type array 17.1.8. .status.conditions[] Description StatefulSetCondition describes the state of a statefulset at a certain point. Type object Required type status Property Type Description lastTransitionTime Time Last time the condition transitioned from one status to another. message string A human readable message indicating details about the transition. reason string The reason for the condition's last transition. status string Status of the condition, one of True, False, Unknown. type string Type of statefulset condition. 17.2. API endpoints The following API endpoints are available: /apis/apps/v1/statefulsets GET : list or watch objects of kind StatefulSet /apis/apps/v1/watch/statefulsets GET : watch individual changes to a list of StatefulSet. deprecated: use the 'watch' parameter with a list operation instead. /apis/apps/v1/namespaces/{namespace}/statefulsets DELETE : delete collection of StatefulSet GET : list or watch objects of kind StatefulSet POST : create a StatefulSet /apis/apps/v1/watch/namespaces/{namespace}/statefulsets GET : watch individual changes to a list of StatefulSet. deprecated: use the 'watch' parameter with a list operation instead. /apis/apps/v1/namespaces/{namespace}/statefulsets/{name} DELETE : delete a StatefulSet GET : read the specified StatefulSet PATCH : partially update the specified StatefulSet PUT : replace the specified StatefulSet /apis/apps/v1/watch/namespaces/{namespace}/statefulsets/{name} GET : watch changes to an object of kind StatefulSet. deprecated: use the 'watch' parameter with a list operation instead, filtered to a single item with the 'fieldSelector' parameter. /apis/apps/v1/namespaces/{namespace}/statefulsets/{name}/status GET : read status of the specified StatefulSet PATCH : partially update status of the specified StatefulSet PUT : replace status of the specified StatefulSet 17.2.1. /apis/apps/v1/statefulsets HTTP method GET Description list or watch objects of kind StatefulSet Table 17.1. HTTP responses HTTP code Reponse body 200 - OK StatefulSetList schema 401 - Unauthorized Empty 17.2.2. /apis/apps/v1/watch/statefulsets HTTP method GET Description watch individual changes to a list of StatefulSet. deprecated: use the 'watch' parameter with a list operation instead. Table 17.2. HTTP responses HTTP code Reponse body 200 - OK WatchEvent schema 401 - Unauthorized Empty 17.2.3. /apis/apps/v1/namespaces/{namespace}/statefulsets HTTP method DELETE Description delete collection of StatefulSet Table 17.3. Query parameters Parameter Type Description dryRun string When present, indicates that modifications should not be persisted. An invalid or unrecognized dryRun directive will result in an error response and no further processing of the request. Valid values are: - All: all dry run stages will be processed Table 17.4. HTTP responses HTTP code Reponse body 200 - OK Status schema 401 - Unauthorized Empty HTTP method GET Description list or watch objects of kind StatefulSet Table 17.5. HTTP responses HTTP code Reponse body 200 - OK StatefulSetList schema 401 - Unauthorized Empty HTTP method POST Description create a StatefulSet Table 17.6. Query parameters Parameter Type Description dryRun string When present, indicates that modifications should not be persisted. An invalid or unrecognized dryRun directive will result in an error response and no further processing of the request. Valid values are: - All: all dry run stages will be processed fieldValidation string fieldValidation instructs the server on how to handle objects in the request (POST/PUT/PATCH) containing unknown or duplicate fields. Valid values are: - Ignore: This will ignore any unknown fields that are silently dropped from the object, and will ignore all but the last duplicate field that the decoder encounters. This is the default behavior prior to v1.23. - Warn: This will send a warning via the standard warning response header for each unknown field that is dropped from the object, and for each duplicate field that is encountered. The request will still succeed if there are no other errors, and will only persist the last of any duplicate fields. This is the default in v1.23+ - Strict: This will fail the request with a BadRequest error if any unknown fields would be dropped from the object, or if any duplicate fields are present. The error returned from the server will contain all unknown and duplicate fields encountered. Table 17.7. Body parameters Parameter Type Description body StatefulSet schema Table 17.8. HTTP responses HTTP code Reponse body 200 - OK StatefulSet schema 201 - Created StatefulSet schema 202 - Accepted StatefulSet schema 401 - Unauthorized Empty 17.2.4. /apis/apps/v1/watch/namespaces/{namespace}/statefulsets HTTP method GET Description watch individual changes to a list of StatefulSet. deprecated: use the 'watch' parameter with a list operation instead. Table 17.9. HTTP responses HTTP code Reponse body 200 - OK WatchEvent schema 401 - Unauthorized Empty 17.2.5. /apis/apps/v1/namespaces/{namespace}/statefulsets/{name} Table 17.10. Global path parameters Parameter Type Description name string name of the StatefulSet HTTP method DELETE Description delete a StatefulSet Table 17.11. Query parameters Parameter Type Description dryRun string When present, indicates that modifications should not be persisted. An invalid or unrecognized dryRun directive will result in an error response and no further processing of the request. Valid values are: - All: all dry run stages will be processed Table 17.12. HTTP responses HTTP code Reponse body 200 - OK Status schema 202 - Accepted Status schema 401 - Unauthorized Empty HTTP method GET Description read the specified StatefulSet Table 17.13. HTTP responses HTTP code Reponse body 200 - OK StatefulSet schema 401 - Unauthorized Empty HTTP method PATCH Description partially update the specified StatefulSet Table 17.14. Query parameters Parameter Type Description dryRun string When present, indicates that modifications should not be persisted. An invalid or unrecognized dryRun directive will result in an error response and no further processing of the request. Valid values are: - All: all dry run stages will be processed fieldValidation string fieldValidation instructs the server on how to handle objects in the request (POST/PUT/PATCH) containing unknown or duplicate fields. Valid values are: - Ignore: This will ignore any unknown fields that are silently dropped from the object, and will ignore all but the last duplicate field that the decoder encounters. This is the default behavior prior to v1.23. - Warn: This will send a warning via the standard warning response header for each unknown field that is dropped from the object, and for each duplicate field that is encountered. The request will still succeed if there are no other errors, and will only persist the last of any duplicate fields. This is the default in v1.23+ - Strict: This will fail the request with a BadRequest error if any unknown fields would be dropped from the object, or if any duplicate fields are present. The error returned from the server will contain all unknown and duplicate fields encountered. Table 17.15. HTTP responses HTTP code Reponse body 200 - OK StatefulSet schema 201 - Created StatefulSet schema 401 - Unauthorized Empty HTTP method PUT Description replace the specified StatefulSet Table 17.16. Query parameters Parameter Type Description dryRun string When present, indicates that modifications should not be persisted. An invalid or unrecognized dryRun directive will result in an error response and no further processing of the request. Valid values are: - All: all dry run stages will be processed fieldValidation string fieldValidation instructs the server on how to handle objects in the request (POST/PUT/PATCH) containing unknown or duplicate fields. Valid values are: - Ignore: This will ignore any unknown fields that are silently dropped from the object, and will ignore all but the last duplicate field that the decoder encounters. This is the default behavior prior to v1.23. - Warn: This will send a warning via the standard warning response header for each unknown field that is dropped from the object, and for each duplicate field that is encountered. The request will still succeed if there are no other errors, and will only persist the last of any duplicate fields. This is the default in v1.23+ - Strict: This will fail the request with a BadRequest error if any unknown fields would be dropped from the object, or if any duplicate fields are present. The error returned from the server will contain all unknown and duplicate fields encountered. Table 17.17. Body parameters Parameter Type Description body StatefulSet schema Table 17.18. HTTP responses HTTP code Reponse body 200 - OK StatefulSet schema 201 - Created StatefulSet schema 401 - Unauthorized Empty 17.2.6. /apis/apps/v1/watch/namespaces/{namespace}/statefulsets/{name} Table 17.19. Global path parameters Parameter Type Description name string name of the StatefulSet HTTP method GET Description watch changes to an object of kind StatefulSet. deprecated: use the 'watch' parameter with a list operation instead, filtered to a single item with the 'fieldSelector' parameter. Table 17.20. HTTP responses HTTP code Reponse body 200 - OK WatchEvent schema 401 - Unauthorized Empty 17.2.7. /apis/apps/v1/namespaces/{namespace}/statefulsets/{name}/status Table 17.21. Global path parameters Parameter Type Description name string name of the StatefulSet HTTP method GET Description read status of the specified StatefulSet Table 17.22. HTTP responses HTTP code Reponse body 200 - OK StatefulSet schema 401 - Unauthorized Empty HTTP method PATCH Description partially update status of the specified StatefulSet Table 17.23. Query parameters Parameter Type Description dryRun string When present, indicates that modifications should not be persisted. An invalid or unrecognized dryRun directive will result in an error response and no further processing of the request. Valid values are: - All: all dry run stages will be processed fieldValidation string fieldValidation instructs the server on how to handle objects in the request (POST/PUT/PATCH) containing unknown or duplicate fields. Valid values are: - Ignore: This will ignore any unknown fields that are silently dropped from the object, and will ignore all but the last duplicate field that the decoder encounters. This is the default behavior prior to v1.23. - Warn: This will send a warning via the standard warning response header for each unknown field that is dropped from the object, and for each duplicate field that is encountered. The request will still succeed if there are no other errors, and will only persist the last of any duplicate fields. This is the default in v1.23+ - Strict: This will fail the request with a BadRequest error if any unknown fields would be dropped from the object, or if any duplicate fields are present. The error returned from the server will contain all unknown and duplicate fields encountered. Table 17.24. HTTP responses HTTP code Reponse body 200 - OK StatefulSet schema 201 - Created StatefulSet schema 401 - Unauthorized Empty HTTP method PUT Description replace status of the specified StatefulSet Table 17.25. Query parameters Parameter Type Description dryRun string When present, indicates that modifications should not be persisted. An invalid or unrecognized dryRun directive will result in an error response and no further processing of the request. Valid values are: - All: all dry run stages will be processed fieldValidation string fieldValidation instructs the server on how to handle objects in the request (POST/PUT/PATCH) containing unknown or duplicate fields. Valid values are: - Ignore: This will ignore any unknown fields that are silently dropped from the object, and will ignore all but the last duplicate field that the decoder encounters. This is the default behavior prior to v1.23. - Warn: This will send a warning via the standard warning response header for each unknown field that is dropped from the object, and for each duplicate field that is encountered. The request will still succeed if there are no other errors, and will only persist the last of any duplicate fields. This is the default in v1.23+ - Strict: This will fail the request with a BadRequest error if any unknown fields would be dropped from the object, or if any duplicate fields are present. The error returned from the server will contain all unknown and duplicate fields encountered. Table 17.26. Body parameters Parameter Type Description body StatefulSet schema Table 17.27. HTTP responses HTTP code Reponse body 200 - OK StatefulSet schema 201 - Created StatefulSet schema 401 - Unauthorized Empty

Commands: