RayService Quickstart#

Prerequisites#

This guide focuses solely on the Ray Serve multi-application API, which is available starting from Ray version 2.4.0.

  • Ray 2.4.0 or newer.

  • KubeRay 0.6.0, KubeRay nightly, or newer.

What’s a RayService?#

A RayService manages these components:

  • RayCluster: Manages resources in a Kubernetes cluster.

  • Ray Serve Applications: Manages users’ applications.

What does the RayService provide?#

  • Kubernetes-native support for Ray clusters and Ray Serve applications: After using a Kubernetes config to define a Ray cluster and its Ray Serve applications, you can use kubectl to create the cluster and its applications.

  • In-place updating for Ray Serve applications: See RayService for more details.

  • Zero downtime upgrading for Ray clusters: See RayService for more details.

  • High-availabilable services: See RayService high availability for more details.

Example: Serve two simple Ray Serve applications using RayService#

Step 1: Create a Kubernetes cluster with Kind#

kind create cluster --image=kindest/node:v1.23.0

Step 2: Install the KubeRay operator#

Follow this document to install the latest stable KubeRay operator via Helm repository. Please note that the YAML file in this example uses serveConfigV2 to specify a multi-application Serve config, which is supported starting from KubeRay v0.6.0.

Step 3: Install a RayService#

# Step 3.1: Download `ray_v1alpha1_rayservice.yaml`
curl -LO https://raw.githubusercontent.com/ray-project/kuberay/v1.0.0/ray-operator/config/samples/ray_v1alpha1_rayservice.yaml

# Step 3.2: Create a RayService
kubectl apply -f ray_v1alpha1_rayservice.yaml

Step 4: Verify the Kubernetes cluster status#

# Step 4.1: List all RayService custom resources in the `default` namespace.
kubectl get rayservice

# [Example output]
# NAME                AGE
# rayservice-sample   2m42s

# Step 4.2: List all RayCluster custom resources in the `default` namespace.
kubectl get raycluster

# [Example output]
# NAME                                 DESIRED WORKERS   AVAILABLE WORKERS   STATUS   AGE
# rayservice-sample-raycluster-6mj28   1                 1                   ready    2m27s

# Step 4.3: List all Ray Pods in the `default` namespace.
kubectl get pods -l=ray.io/is-ray-node=yes

# [Example output]
# ervice-sample-raycluster-6mj28-worker-small-group-kg4v5   1/1     Running   0          3m52s
# rayservice-sample-raycluster-6mj28-head-x77h4             1/1     Running   0          3m52s

# Step 4.4: List services in the `default` namespace.
kubectl get services

# NAME                                          TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)                                                   AGE
# ...
# rayservice-sample-head-svc                    ClusterIP   10.96.34.90     <none>        10001/TCP,8265/TCP,52365/TCP,6379/TCP,8080/TCP,8000/TCP   4m58s
# rayservice-sample-raycluster-6mj28-head-svc   ClusterIP   10.96.171.184   <none>        10001/TCP,8265/TCP,52365/TCP,6379/TCP,8080/TCP,8000/TCP   6m21s
# rayservice-sample-serve-svc                   ClusterIP   10.96.161.84    <none>        8000/TCP                                                  4m58s

When the Ray Serve applications are healthy and ready, KubeRay creates a head service and a Ray Serve service for the RayService custom resource. For example, rayservice-sample-head-svc and rayservice-sample-serve-svc in Step 4.4.

Step 5: Verify the status of the Serve applications#

# (1) Forward the dashboard port to localhost.
# (2) Check the Serve page in the Ray dashboard at http://localhost:8265/#/serve.
kubectl port-forward svc/rayservice-sample-head-svc --address 0.0.0.0 8265:8265
  • Refer to rayservice-troubleshooting.md for more details on RayService observability. Below is a screenshot example of the Serve page in the Ray dashboard. Ray Serve Dashboard

Step 6: Send requests to the Serve applications via the Kubernetes serve service#

# Step 6.1: Run a curl Pod.
# If you already have a curl Pod, you can use `kubectl exec -it <curl-pod> -- sh` to access the Pod.
kubectl run curl --image=radial/busyboxplus:curl -i --tty

# Step 6.2: Send a request to the fruit stand app.
curl -X POST -H 'Content-Type: application/json' rayservice-sample-serve-svc:8000/fruit/ -d '["MANGO", 2]'
# [Expected output]: 6

# Step 6.3: Send a request to the calculator app.
curl -X POST -H 'Content-Type: application/json' rayservice-sample-serve-svc:8000/calc/ -d '["MUL", 3]'
# [Expected output]: "15 pizzas please!"

Step 7: Clean up the Kubernetes cluster#

# Delete the RayService.
kubectl delete -f ray_v1alpha1_rayservice.yaml

# Uninstall the KubeRay operator.
helm uninstall kuberay-operator

# Delete the curl Pod.
kubectl delete pod curl

Next steps#

  • See RayService document for the full list of RayService features, including in-place update, zero downtime upgrade, and high-availability.

  • See RayService troubleshooting guide if you encounter any issues.

  • See Examples for more RayService examples. The MobileNet example is a good example to start with because it does not require GPUs and is easy to run on a local machine.