> ## Documentation Index > Fetch the complete documentation index at: https://docs.idyl.network/llms.txt > Use this file to discover all available pages before exploring further. # HostPodSet > YAML manifest fields for IDYL HostPodSet resources. A HostPodSet keeps a counted set of host Pods. A host Pod runs no workload of its own: it reserves a CPU and memory envelope on a node for isolated units that a node agent creates inside it later, through the node's own contract. The HostPodSet decides how many hosts exist, where they may be placed, and the isolation class of the units they hold; it says nothing about what those units run or for whom beyond its opaque owner. A HostPodSet is reconciled like a ReplicaSet: the platform creates and removes host Pods until the placed set matches the desired count, and when the template changes it replaces hosts according to the strategy, draining each host before it is removed. ## Minimal manifest ```yaml theme={null} kind: HostPodSet metadata: name: sandbox-hosts subnet: "100000000001" spec: owner: example.com/sandboxes hosts: max: 4 strategy: type: RollingUpdate template: isolation: secure-container capacity: cpu: "2" memory: 4Gi ``` ## Example manifest ```yaml theme={null} kind: HostPodSet metadata: name: sandbox-hosts subnet: "100000000001" labels: app: sandbox-hosts spec: owner: example.com/sandboxes hosts: count: 2 min: 1 max: 8 strategy: type: RollingUpdate rollingUpdate: maxUnavailable: 1 maxSurge: 1 template: isolation: microvm capacity: cpu: "4" memory: 8Gi placement: fleet: "391742608215" ``` ## Field reference kind string Required Resource kind. The value is case-sensitive.Value `HostPodSet` metadata object Required Top-level workload metadata. metadata.namespace object Optional Namespace scope embedded in the manifest. Scoped SDK clients populate it when omitted and refuse a manifest that states a different scope.Format Explicit scope or SDK client scope metadata.namespace.accountId string Optional Account that owns the Namespace.Format 12-digit account ID metadata.namespace.namespace string Optional Namespace name within the Account. metadata.subnet string Optional Canonical subnet identifier where the workload should run.Format Explicit scope or SDK placement metadata.name string Required Stable workload name within the namespace. metadata.labels map\[string]string Optional User-defined labels for grouping, filtering, and ownership metadata. metadata.annotations map\[string]string Optional User-defined annotations for descriptive metadata that is not used for identity. spec object Required Desired HostPodSet configuration. spec.owner string Required Names whom the hosts serve. The platform treats it as an opaque label: it is set at creation and never changes. It is 1 to 128 characters of lowercase letters, digits, `-`, `.`, and `/`, beginning and ending with a letter or digit. spec.controller object Optional The resource that controls this HostPodSet. It is set only at creation, only by a caller the platform authorizes as that controller, and never changes afterwards; the platform never adopts a HostPodSet by matching its name or labels. The hosts are served by the DaemonSet that carries the same controller. spec.controller.kind string Required Kind of the controlling resource, as its lowercase resource kind token.Example `supervisor` spec.controller.id string Required ID of the controlling resource: the identity it keeps for its whole life.Format Canonical UUID spec.hosts object Required Desired host count and the bounds it must stay within. spec.hosts.count integer Optional Number of hosts to keep placed, between min and max.Default `0` spec.hosts.min integer Optional Fewest hosts the set may be scaled to. A value above zero is a warm reservation: that many hosts stay placed while they hold nothing.Default `0` spec.hosts.max integer Required Most hosts the set may be scaled to.Requirement At least `1` spec.strategy object Required Host replacement strategy. spec.strategy.type string Required Replacement strategy type.Value `RollingUpdate` spec.strategy.rollingUpdate object Optional Rolling update controls. When omitted, the documented defaults of each control apply. spec.strategy.rollingUpdate.maxUnavailable integer Optional Maximum number of hosts that may be out of service because of the replacement, counting a host while it drains.Default `1` spec.strategy.rollingUpdate.maxSurge integer Optional Maximum number of hosts that may be placed above the desired count while replacements are made.Default `0` spec.template object Required Template every host is made from. spec.template.isolation string Required Isolation class of the units the host holds. Possible enum values: spec.template.gpu quantity string Optional GPU devices one host reserves for the units it holds.Examples `h100`, `2:h100`, `nvidia:24Gi` spec.template.capacity object Required CPU and memory one host reserves. spec.template.capacity.cpu quantity string Required CPU one host reserves.Examples `500m`, `2` spec.template.capacity.memory quantity string Required Memory one host reserves.Examples `512Mi`, `4Gi` spec.template.placement object Optional Restricts hosts to the nodes of one fleet inside the subnet. If omitted, a host may be placed on any eligible node of the subnet. spec.template.placement.fleet string Required Restricts placement to eligible members of this fleet.Format 12-digit fleet ID ## Read-only fields IDYL can return these fields when you inspect a workload. Do not include them in authored manifests. | Field | Description | | - | - | | `metadata.id` | IDYL-assigned resource ID. | | `metadata.namespace.id` | IDYL-assigned namespace ID. | | `metadata.ownerReferences` | Parent workload relationship, such as a ReplicaSet owned by a Deployment. | | `metadata.createdAt` | Creation timestamp. | | `metadata.updatedAt` | Last update timestamp. | | `metadata.deletedAt` | Deletion timestamp, when present. | | `metadata.revision` | Revision information returned by IDYL. | | `status` | Current observed state returned by IDYL. | ## Validation notes * `kind` values are case-sensitive. * At least one container is required in every pod spec. * At least one container must specify CPU or memory in `resources.requests` or `resources.limits`, unless the CLI fills those values from configured defaults before sending the workload. * GPU requirements belong at the pod spec `gpu` path, not under per-container resources. * Environment variable names must be unique within a container and must match `[a-zA-Z_][a-zA-Z0-9_]*`. 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