(kuberay-batch-inference-example)= # RayJob Batch Inference Example This example demonstrates how to use the RayJob custom resource to run a batch inference job for an image classification workload on a Ray cluster. See [Image Classification Batch Inference with HuggingFace Vision Transformer](https://docs.ray.io/en/latest/data/examples/huggingface_vit_batch_prediction.html) for a full explanation of the code. ## Prerequisites You must have a Kubernetes cluster running,`kubectl` configured to use it, and GPUs available. This example provides a brief tutorial for setting up the necessary GPUs on Google Kubernetes Engine (GKE), but you can use any Kubernetes cluster with GPUs. ## Step 0: Create a Kubernetes cluster on GKE (Optional) If you already have a Kubernetes cluster with GPUs, you can skip this step. Otherwise, follow [this tutorial](kuberay-gke-gpu-cluster-setup), but substitute the following GPU node pool creation command to create a Kubernetes cluster on GKE with four Nvidia T4 GPUs: ```sh gcloud container node-pools create gpu-node-pool \ --accelerator type=nvidia-tesla-t4,count=4,gpu-driver-version=default \ --zone us-west1-b \ --cluster kuberay-gpu-cluster \ --num-nodes 1 \ --min-nodes 0 \ --max-nodes 1 \ --enable-autoscaling \ --machine-type n1-standard-64 ``` This example uses four [Nvidia T4](https://cloud.google.com/compute/docs/gpus#nvidia_t4_gpus) GPUs. The machine type is `n1-standard-64`, which has [64 vCPUs and 240 GB RAM](https://cloud.google.com/compute/docs/general-purpose-machines#n1_machine_types). ## Step 1: Install the KubeRay Operator Follow [this document](kuberay-operator-deploy) to install the latest stable KubeRay operator from the Helm repository. The KubeRay operator Pod must be on the CPU node if you have set up the taint for the GPU node pool correctly. ## Step 2: Submit the RayJob Create the RayJob custom resource with [ray-job.batch-inference.yaml](https://github.com/ray-project/kuberay/blob/v1.3.0/ray-operator/config/samples/ray-job.batch-inference.yaml). Download the file with `curl`: ```bash curl -LO https://raw.githubusercontent.com/ray-project/kuberay/v1.3.0/ray-operator/config/samples/ray-job.batch-inference.yaml ``` Note that the `RayJob` spec contains a spec for the `RayCluster`. This tutorial uses a single-node cluster with 4 GPUs. For production use cases, use a multi-node cluster where the head node doesn't have GPUs, so that Ray can automatically schedule GPU workloads on worker nodes which won't interfere with critical Ray processes on the head node. Note the following fields in the `RayJob` spec, which specify the Ray image and the GPU resources for the Ray node: ```yaml spec: containers: - name: ray-head image: rayproject/ray-ml:2.6.3-gpu resources: limits: nvidia.com/gpu: "4" cpu: "54" memory: "54Gi" requests: nvidia.com/gpu: "4" cpu: "54" memory: "54Gi" volumeMounts: - mountPath: /home/ray/samples name: code-sample nodeSelector: cloud.google.com/gke-accelerator: nvidia-tesla-t4 # This is the GPU type we used in the GPU node pool. ``` To submit the job, run the following command: ```bash kubectl apply -f ray-job.batch-inference.yaml ``` Check the status with `kubectl describe rayjob rayjob-sample`. Sample output: ``` [...] Status: Dashboard URL: rayjob-sample-raycluster-j6t8n-head-svc.default.svc.cluster.local:8265 End Time: ... Job Deployment Status: Complete Job Id: rayjob-sample-ft8lh Job Status: SUCCEEDED Message: Job finished successfully. Observed Generation: 2 ... ``` To view the logs, first find the name of the pod running the job with `kubectl get pods`. Sample output: ```bash NAME READY STATUS RESTARTS AGE kuberay-operator-8b86754c-r4rc2 1/1 Running 0 25h rayjob-sample-raycluster-j6t8n-head-kx2gz 1/1 Running 0 35m rayjob-sample-w98c7 0/1 Completed 0 30m ``` The Ray cluster is still running because `shutdownAfterJobFinishes` isn't set in the `RayJob` spec. If you set `shutdownAfterJobFinishes` to `true`, the cluster is shut down after the job finishes. Next, run: ```text kubectl logs rayjob-sample-w98c7 ``` to get the standard output of the `entrypoint` command for the `RayJob`. Sample output: ```text [...] Running: 62.0/64.0 CPU, 4.0/4.0 GPU, 955.57 MiB/12.83 GiB object_store_memory: 0%| | 0/200 [00:05 Label: tench, Tinca tinca Label: tench, Tinca tinca Label: tench, Tinca tinca Label: tench, Tinca tinca Label: tench, Tinca tinca 2023-08-22 15:48:36,522 SUCC cli.py:33 -- ----------------------------------- 2023-08-22 15:48:36,522 SUCC cli.py:34 -- Job 'rayjob-sample-ft8lh' succeeded 2023-08-22 15:48:36,522 SUCC cli.py:35 -- ----------------------------------- ```