> ## Documentation Index > Fetch the complete documentation index at: https://docs.ornn.com/llms.txt > Use this file to discover all available pages before exploring further. # Add a physical worker > Adds one host to an owned cluster that is not failed or being torn down. The host must be in bare-metal status, not in another cluster, and on an active reservation your organization owns; it can come from a different reservation than the one the cluster launched on. A VM and its host cannot both be cluster workers. A new host normally returns state cleaning. Ornn first prepares the host - running processes are stopped, the tenant home directory is wiped, and any VM on that host is removed - and the host then appears in the cluster's nodes in listClusters with state joining, then ready. Repeating the request is safe. It returns cleaning while preparation is pending, or the current membership state once the host is a member. For Kubernetes, adding a worker does not raise the GPU quota of the namespace Ornn configured, which is sized when the cluster first becomes active. A host from another reservation is labeled and tainted with its own reservation, while pods in that namespace are pinned to the reservation the cluster launched on. Verify Node readiness, allocatable GPUs, and the namespace quota through the Kubernetes API before scheduling more work. See [Scale workers up or down](/guides/kubernetes-api#6-scale-workers-up-or-down) for polling and Kubernetes checks. CLI equivalent, after `ornn login`: ```bash theme={null} ornn clusters add-node CLUSTER_ID NODE_ID ``` ## OpenAPI ````yaml openapi.yaml POST /v1/orchestrator/controllers/{controller_id}/nodes/{node_id} openapi: 3.1.0 info: title: Ornn compute API version: 1.0.0 description: >- Customer HTTP API for Ornn GPU capacity. It covers reserved capacity and nodes, VM and Bare Metal access, Kubernetes and Slurm clusters, SSH keys, storage volumes and GitHub repositories, private networks, monitoring, buying and selling capacity (Reserve, Market, Spot, and Relist), and billing. API keys are scoped to one organization and act with their creator's access there; account, team, and API-key management stay in the console. Most operations require an approved organization. See https://docs.ornn.com/api-keys to create a key and https://docs.ornn.com/guides/kubernetes-api for an end-to-end Kubernetes integration. Examples use fictional IDs and credentials. The info.version field identifies the contract revision, not a shared API path version. contact: email: support@ornn.com servers: - url: https://api.ornn.com description: Production security: - OrnnApiKey: [] tags: - name: Authentication - name: Reservations - name: GPU nodes - name: Clusters - name: Workers - name: Virtual machines description: >- Choose a VM disk, launch VM access on a reservation, and read each VM's status, launch progress, and SSH connection details. - name: Bare Metal description: >- Launch Bare Metal access on a reservation, read a host's readiness and SSH connection details, and reboot or hard reset it. - name: SSH keys description: >- Register public keys for your organization, choose which keys a VM or Bare Metal reservation uses, and queue key delivery to machines. Slurm clusters take organization key IDs at launch. Kubernetes API access does not use SSH keys. - name: Reserve description: >- Browse reserved-capacity listings and their terms, and post, cancel, or accept offers. Reserve listings are visible to approved organizations. - name: Market description: >- Browse relisted capacity and buy windows at the asking price, paid up front. Open to every member of your organization. - name: Spot description: >- Hourly order books for VMs with 1, 2, 4, or 8 GPUs on one node: read books, trades, and quotes, place and cancel bids, and follow fills. - name: Relist description: >- Sell whole nodes from a reservation you hold at your asking price, and manage those listings. - name: Storage description: >- Managed volumes, their files, and GitHub repository pulls. Volumes belong to the API key's creator in the key's organization. - name: Networks description: >- Organization private networks and the WireGuard configs you use to reach private machines and clusters. - name: Monitoring description: >- Machine telemetry and console logs for capacity your organization holds. Reads are limited to your reservation window. - name: Billing description: >- Invoices, billing summary, usage cost, Ornn credits, and account statements. Saving a card and paying invoices stay in the console. externalDocs: description: REST integration walkthrough url: >- https://docs.ornn.com/guides/kubernetes-access#provision-and-manage-through-rest paths: /v1/orchestrator/controllers/{controller_id}/nodes/{node_id}: post: tags: - Workers summary: Add a physical worker description: >- Adds one host to an owned cluster that is not failed or being torn down. The host must be in bare-metal status, not in another cluster, and on an active reservation your organization owns; it can come from a different reservation than the one the cluster launched on. A VM and its host cannot both be cluster workers. A new host normally returns state cleaning. Ornn first prepares the host - running processes are stopped, the tenant home directory is wiped, and any VM on that host is removed - and the host then appears in the cluster's nodes in listClusters with state joining, then ready. Repeating the request is safe. It returns cleaning while preparation is pending, or the current membership state once the host is a member. For Kubernetes, adding a worker does not raise the GPU quota of the namespace Ornn configured, which is sized when the cluster first becomes active. A host from another reservation is labeled and tainted with its own reservation, while pods in that namespace are pinned to the reservation the cluster launched on. Verify Node readiness, allocatable GPUs, and the namespace quota through the Kubernetes API before scheduling more work. operationId: addNode parameters: - name: controller_id in: path required: true description: Cluster id returned by create or list; not a reservation ID. schema: type: string format: uuid example: 44444444-4444-4444-8444-444444444444 - name: node_id in: path required: true description: An existing owned physical worker ID. schema: type: string format: uuid example: 33333333-3333-4333-8333-333333333333 responses: '202': description: >- Addition accepted, or the host is already a member. Preparation and joining continue asynchronously. content: application/json: schema: $ref: '#/components/schemas/WorkerChange' example: controller_id: 44444444-4444-4444-8444-444444444444 node_id: 33333333-3333-4333-8333-333333333333 state: cleaning '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '404': description: >- The cluster is absent, failed, or being torn down, or the host is not owned. content: application/json: schema: $ref: '#/components/schemas/Error' examples: cluster: summary: Cluster absent, failed, or being torn down value: detail: code: controller_not_found message: >- Ornn could not find that cluster. It may already be torn down. node: summary: Host not owned or not found value: detail: code: node_not_found message: Ornn could not find that node in this cluster. '409': description: >- The host cannot join. A 409 with an empty JSON object means the host already belongs to another cluster or runs another workload. content: application/json: schema: $ref: '#/components/schemas/Error' examples: notBareMetal: summary: The host or an existing member is not in bare-metal status value: detail: code: cluster_nodes_not_available message: >- One or more selected nodes are no longer available. Refresh the node list and try again. reservationEnded: summary: >- The host's reservation ended, was cancelled, or has a pending change value: detail: code: reservation_not_launchable message: This reservation cannot launch in its current state. noReservation: summary: The host is not on a reservation value: detail: code: node_reservation_missing message: >- This node is not part of a reservation, so it cannot join a cluster. inUse: summary: The host belongs to another cluster value: {} default: $ref: '#/components/responses/Error' components: schemas: WorkerChange: type: object required: - controller_id - state properties: controller_id: type: string format: uuid node_id: type: string format: uuid virtual_machine_id: type: string format: uuid state: type: string description: >- On a new addition, cleaning while Ornn prepares the host or joining when it attaches directly. On a repeated addition, the current membership state, such as joining or ready, or cleaning while preparation is still pending. On removal, draining. Error: type: object properties: code: type: string detail: oneOf: - type: string - type: object required: - code - message properties: code: type: string message: type: string responses: Unauthorized: description: >- The credential is missing, invalid, revoked, or no longer belongs to a current organization member. Check the HTTP status before parsing the body. content: application/json: schema: $ref: '#/components/schemas/Error' Forbidden: description: >- The credential lacks access to this operation, or the organization requires approval. An API key does not bypass these checks. content: application/json: schema: $ref: '#/components/schemas/Error' Error: description: >- Unsuccessful request. Check HTTP status first. Errors may have detail.code/detail.message, a string detail and optional top-level code, or an empty/non-JSON body. 401: invalid credential; 403: access or approval required; 404: not visible or credentials not ready; 409: lifecycle conflict; 429: back off; 5xx: service failure. Inspect current state before retrying mutations. content: application/json: schema: $ref: '#/components/schemas/Error' securitySchemes: OrnnApiKey: type: http scheme: bearer bearerFormat: ornn_sk_... description: >- Create an organization API key in Account Settings > Developer. Do not send this key to the Kubernetes API server. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.