Slice

Slice is a custom resource definition that lets you define and manage accelerator slices in Google Kubernetes Engine (GKE). This resource lets you group TPU partitions to form larger slices for distributed training workloads.

When you create or update a Slice custom resource, a validating webhook is triggered to ensure that the resource specification is valid. This validation helps to ensure that only valid Slice definitions are accepted by the Kubernetes API server.

apiVersion: accelerator.gke.io/v1beta1
kind: Slice
metadata:
  name: test-slice
spec:
  type: "tpu7x"
  topology: "4x4x8"
  partitionIds:
    - a9476d1b02bd4f4e75ffffae3bd23c01
    - ba898ffcac0ad0946e8ff036d771ee53
status:
  conditions:
  - type: Ready
    status: "False"
    reason: FAILED
    message: ""
    lastTransitionTime: "2026-01-11T23:45:38Z"

Slice specification

metadata:
  name: string
spec:
  type: string
  topology: string
  partitionIds: []string

Fields
metadata.name required	string The name of the Slice resource. It must adhere to the following rules to ensure compatibility with underlying Compute Engine resource naming conventions: Length: the name must be 49 characters or fewer. The controller appends a hyphen and an 8-character cluster hash to create Compute Engine resource names, which have a 63-character limit. Format: it must match the following regular expression: ^[a-z]([-a-z0-9]*[a-z0-9])?$. This match means the name has the following characteristics: Must start with a lowercase letter. Can contain only lowercase letters, numbers, and hyphens (-). Must end with a lowercase letter or a number (it can't end with a hyphen).
metadata.annotations optional	object Annotations for the Slice resource. slice.gke.io/retry-on-failure: "true" If set to "true", the slice controller will retry the creation of the slice if it fails.
type required	string The type of accelerator for this slice. The type field must be one of the following supported values: tpu7x Any other value will be rejected.
topology required	string The topology for the accelerator slice. Requirements for the tpu7x accelerator topology include the following rules: The topology must be a three-dimensional string in following format: AxBxC. For example, 4x8x8. For dynamic sub-slicing (topologies smaller than 4x4x4), you can specify 2x2x1, 2x2x2, 2x2x4, or 2x4x4. Requires GKE version 1.36.0-gke.3712000 or later. For dynamic super-slicing (topologies greater than or equal to 4x4x4), each dimension of the requested topology must be a multiple of four. Requires GKE version 1.35.2-gke.1842000 or later. The dimensions must be sorted in non-decreasing order: A <= B <= C. For example, 4x8x4 is invalid; it should be 4x4x8. The product of the dimensions (A*B*C) must not exceed 9,216.
partitionIds required	string[] A list of strings that identify the partitions making up the slice. All values within the partitionIds list must be unique. Duplicate partition IDs are not allowed. Requirements include the following: For dynamic sub-slicing (smaller than 4x4x4), you must specify exactly one partition ID. Requires GKE version 1.36.0-gke.3712000 or later. For sub-blocks equal to or larger than 4x4x4, the number of partitions is calculated based on the total number of chips, where each partition consists of 64 chips. The number of items in your spec.partitionIds list must exactly match the calculated number of partitions ((A*B*C) / 64).

Slice status

conditions:
- type: string
  status: string
  reason: string
  message: string
  lastTransitionTime: string

Fields
conditions[]	object List of status conditions for the Slice.
conditions.type	string Condition type.
conditions.status	string Condition status. Possible values are True or False.
conditions.reason	string A short description of the lifecycle state of the slice. Possible values include the following: SliceNotCreated: the slice hasn't been created yet. The slice controller is currently initializing and performing preflight checks for slice formation. SliceCreationFailed: creation failed because prerequisites were not met (for example, required Compute Engine resources are missing) or preflight checks failed. To automatically retry slice formation in this state, configure the slice.gke.io/retry-on-failure: "true" annotation. ACTIVATING: the slice is in the process of being formed (stitched). ACTIVE: the slice is fully formed, healthy, and ready to execute workloads. ACTIVE_DEGRADED: the slice is formed but includes degraded cubes, supported by ICI resilience. Workloads can run, but performance might be impacted. Dynamic super-slicing is resilient to single optical circuit switch (OCS) failures. If a single OCS unit fails, all optical links traversing that switch become unavailable, which causes all cubes within the superpod to operate in a degraded state. This state applies only to the top-level 4x4x4 topology. Smaller topologies don't have a degraded state. DEACTIVATING: the slice is in the process of being dismantled. FAILED: the slice is no longer ready to execute workloads. This state occurs if initial formation failed or if an active slice experienced a critical software or hardware failure. INCOMPLETE: for dynamic sub-slicing, this is the terminal step before the resource is fully deleted. For dynamic super-slicing, there are not enough available cubes to initiate super-slice formation.
conditions.message	string A detailed description of the condition's status.
conditions.lastTransitionTime	string A timestamp of the most recent status change.