--- title: Access DRA Device Metadata content_type: task min-kubernetes-server-version: v1.36 weight: 30 --- {{< feature-state state="alpha" for_k8s_version="v1.36" >}} This page shows you how to access [device metadata](/docs/concepts/scheduling-eviction/dynamic-resource-allocation/#device-metadata) from containers that use _dynamic resource allocation (DRA)_. Device metadata lets workloads discover information about allocated devices such as device attributes or network interface details — by reading JSON files at well-known paths inside the container. Before reading this page, familiarize yourself with [Dynamic Resource Allocation (DRA)](/docs/concepts/scheduling-eviction/dynamic-resource-allocation/) and how to [allocate devices to workloads](/docs/tasks/configure-pod-container/assign-resources/allocate-devices-dra/). ## {{% heading "prerequisites" %}} {{< include "task-tutorial-prereqs.md" >}} {{< version-check >}} * Ensure that your cluster admin has set up DRA, attached devices, and installed drivers. For more information, see [Set Up DRA in a Cluster](/docs/tasks/configure-pod-container/assign-resources/set-up-dra-cluster). * Ensure that the DRA driver deployed in your cluster supports device metadata. Drivers that use the [DRA kubelet plugin](https://pkg.go.dev/k8s.io/dynamic-resource-allocation/kubeletplugin) enable the `EnableDeviceMetadata` and `MetadataVersions` options when starting the plugin. Check the driver's documentation for details. ## Access device metadata with a ResourceClaim {#access-metadata-resourceclaim} When you use a directly referenced ResourceClaim to allocate devices, the device metadata files appear inside the container at: ``` /var/run/kubernetes.io/dra-device-attributes/resourceclaims///-metadata.json ``` 1. Review the following example manifest: {{% code_sample file="dra/dra-device-metadata-pod.yaml" %}} This manifest creates a ResourceClaim named `gpu-claim` that requests a device from the `gpu.example.com` DeviceClass, and a Pod that reads the device metadata. 1. Create the ResourceClaim and Pod: ```shell kubectl apply -f https://k8s.io/examples/dra/dra-device-metadata-pod.yaml ``` 1. After the Pod is running, view the container logs to see the metadata: ```shell kubectl logs gpu-metadata-reader ``` The output is similar to: ``` === DRA device metadata === /var/run/kubernetes.io/dra-device-attributes/resourceclaims/gpu-claim/gpu/gpu.example.com-metadata.json { "kind": "DeviceMetadata", "apiVersion": "metadata.resource.k8s.io/v1alpha1", ... } ``` 1. To inspect the full metadata file, exec into the container: ```shell kubectl exec gpu-metadata-reader -- \ cat /var/run/kubernetes.io/dra-device-attributes/resourceclaims/gpu-claim/gpu/gpu.example.com-metadata.json ``` The output is a JSON object containing device attributes like the model, driver version, and device UUID. See [metadata schema](/docs/concepts/scheduling-eviction/dynamic-resource-allocation/#device-metadata-schema) for details on the JSON structure. ## Access device metadata with a ResourceClaimTemplate {#access-metadata-template} When you use a ResourceClaimTemplate, Kubernetes generates a ResourceClaim for each Pod. Because the generated claim name is not predictable, the metadata files appear at a path that uses the Pod's claim reference name instead: ``` /var/run/kubernetes.io/dra-device-attributes/resourceclaimtemplates///-metadata.json ``` The `` corresponds to the `name` field in the Pod's `spec.resourceClaims[]` entry. The JSON metadata also includes a `podClaimName` field that records this mapping. 1. Review the following example manifest: {{% code_sample file="dra/dra-device-metadata-template-pod.yaml" %}} This manifest creates a ResourceClaimTemplate and a Pod. Each Pod gets its own generated ResourceClaim. The metadata path uses the Pod's claim reference name `my-gpu`. 1. Create the ResourceClaimTemplate and Pod: ```shell kubectl apply -f https://k8s.io/examples/dra/dra-device-metadata-template-pod.yaml ``` 1. After the Pod is running, view the metadata: ```shell kubectl exec gpu-metadata-template-reader -- \ cat /var/run/kubernetes.io/dra-device-attributes/resourceclaimtemplates/my-gpu/gpu/gpu.example.com-metadata.json ``` ## Read metadata in your application {#read-metadata-application} ### Go applications The `k8s.io/dynamic-resource-allocation/devicemetadata` package provides ready-made functions for reading metadata files. These functions handle version negotiation automatically, decoding the metadata stream and converting it to internal types so your code works across schema versions without manual version checks. For a directly referenced ResourceClaim: ```go import "k8s.io/dynamic-resource-allocation/devicemetadata" dm, err := devicemetadata.ReadResourceClaimMetadata("gpu-claim", "gpu") ``` For a template-generated claim (using the Pod's claim reference name): ```go dm, err := devicemetadata.ReadResourceClaimTemplateMetadata("my-gpu", "gpu") ``` If you know the specific driver name, you can read a single driver's metadata file: ```go dm, err := devicemetadata.ReadResourceClaimMetadataWithDriverName("gpu.example.com", "gpu-claim", "gpu") ``` The returned `*metadata.DeviceMetadata` contains the claim metadata, requests, and per-device attributes. Applications in other languages can read the JSON file directly and inspect the `apiVersion` field to determine the schema version before parsing. ## Clean up {#clean-up} Delete the resources that you created: ```shell kubectl delete -f https://k8s.io/examples/dra/dra-device-metadata-pod.yaml kubectl delete -f https://k8s.io/examples/dra/dra-device-metadata-template-pod.yaml ``` ## {{% heading "whatsnext" %}} * [Learn more about DRA device metadata](/docs/concepts/scheduling-eviction/dynamic-resource-allocation/#device-metadata) * [Allocate devices to workloads with DRA](/docs/tasks/configure-pod-container/assign-resources/allocate-devices-dra/) * For more information on the design, see [KEP-5304](https://github.com/kubernetes/enhancements/tree/master/keps/sig-node/5304-dra-attributes-downward-api).