Serve an LLM with GKE Inference Gateway


This tutorial describes how to deploy a large language model (LLM) on Google Kubernetes Engine (GKE) with the GKE Inference Gateway. The tutorial includes steps for cluster setup, model deployment, GKE Inference Gateway configuration, and handling LLM requests.

This tutorial is for Machine learning (ML) engineers, Platform admins and operators, and Data and AI specialists who want to deploy and manage LLM applications using LLMs on GKE with GKE Inference Gateway.

Before you read this page, familiarize yourself with the following:

Background

This section describes the key technologies used in this tutorial. For more information about model serving concepts and terminology, and how GKE generative AI capabilities can enhance and support your model serving performance, see About model inference on GKE .

vLLM

vLLM is a highly optimized open source LLM serving framework that increases serving throughput on GPUs, with features such as the following:

  • Optimized transformer implementation with PagedAttention
  • Continuous batching that improves the overall serving throughput
  • Tensor parallelism and distributed serving across multiple GPUs

To learn more, refer to the vLLM documentation .

GKE Inference Gateway

GKE Inference Gateway enhances the capabilities of GKE for serving LLMs. It optimizes inference workloads with features such as the following:

  • Inference-optimized load balancing based on load metrics.
  • Support for dense multi-workload serving of LoRA adapters.
  • Model-aware routing for simplified operations.

For more information, see About GKE Inference Gateway .

Objectives

  1. Get access to the model .
  2. Prepare your environment .
  3. Create and configure Google Cloud resources .
  4. Install the InferenceModel and InferencePool CRDs .
  5. Deploy the model server .
  6. Configure observability for your Inference Gateway .

Before you begin

  • Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.
  • In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

    Go to project selector

  • Verify that billing is enabled for your Google Cloud project .

  • Enable the required API.

    Enable the API

  • In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

    Go to project selector

  • Verify that billing is enabled for your Google Cloud project .

  • Enable the required API.

    Enable the API

  • Make sure that you have the following role or roles on the project: roles/container.admin, roles/iam.serviceAccountAdmin

    Check for the roles

    1. In the Google Cloud console, go to the IAM page.

      Go to IAM
    2. Select the project.
    3. In the Principal column, find all rows that identify you or a group that you're included in. To learn which groups you're included in, contact your administrator.

    4. For all rows that specify or include you, check the Role column to see whether the list of roles includes the required roles.

    Grant the roles

    1. In the Google Cloud console, go to the IAM page.

      Go to IAM
    2. Select the project.
    3. Click Grant access .
    4. In the New principals field, enter your user identifier. This is typically the email address for a Google Account.

    5. In the Select a role list, select a role.
    6. To grant additional roles, click Add another role and add each additional role.
    7. Click Save .

Get access to the model

To deploy the Llama3.1 model to GKE, sign the license consent agreement and generate a Hugging Face access token.

You must sign the consent agreement to use the Llama3.1 model. Follow these instructions:

  1. Access consent page and verify consent for using your Hugging Face account.
  2. Accept the model terms.

Generate an access token

To access the model through Hugging Face, you need a Hugging Face token .

Follow these steps to generate a new token if you don't have one already:

  1. Click Your Profile > Settings > Access Tokens.
  2. Select New Token.
  3. Specify a name of your choice and a role of at least Read .
  4. Select Generate a token.
  5. Copy the generated token to your clipboard.

Prepare your environment

In this tutorial, you use Cloud Shell to manage resources hosted on Google Cloud. Cloud Shell comes preinstalled with the software you need for this tutorial, including kubectl and gcloud CLI .

To set up your environment with Cloud Shell, perform the following steps:

  1. In the Google Cloud console, launch a Cloud Shell session by clickingCloud Shell activation icon Activate Cloud Shellin the Google Cloud console . This launches a session in the bottom pane of Google Cloud console.

  2. Set the default environment variables:

     gcloud  
    config  
     set 
      
    project  
     PROJECT_ID 
    gcloud  
    config  
     set 
      
    billing/quota_project  
     PROJECT_ID 
     export 
      
     PROJECT_ID 
     = 
     $( 
    gcloud  
    config  
    get  
    project ) 
     export 
      
     REGION 
     = 
     REGION 
     export 
      
     CLUSTER_NAME 
     = 
     CLUSTER_NAME 
     export 
      
     HF_TOKEN 
     = 
     HF_TOKEN 
     
    

    Replace the following values:

    • PROJECT_ID : your Google Cloud project ID .
    • REGION : a region that supports the accelerator type you want to use, for example, us-central1 for H100 GPU.
    • CLUSTER_NAME : the name of your cluster.
    • HF_TOKEN : the Hugging Face token you generated earlier.

Create and configure Google Cloud resources

To create the required resources, use these instructions.

Create a GKE cluster and node pool

Serve LLMs on GPUs in a GKE Autopilot or Standard cluster. We recommend that you use a Autopilot cluster for a fully managed Kubernetes experience. To choose the GKE mode of operation that's the best fit for your workloads, see Choose a GKE mode of operation .

Autopilot

In Cloud Shell, run the following command:

 gcloud  
container  
clusters  
create-auto  
 CLUSTER_NAME 
  
 \ 
  
--project = 
 PROJECT_ID 
  
 \ 
  
--location = 
 CONTROL_PLANE_LOCATION 
  
 \ 
  
--release-channel = 
rapid 

Replace the following values:

  • PROJECT_ID : your Google Cloud project ID .
  • CONTROL_PLANE_LOCATION : the Compute Engine region of the control plane of your cluster. Provide a region that supports the accelerator type you want to use, for example, us-central1 for H100 GPU.
  • CLUSTER_NAME : the name of your cluster.

GKE creates an Autopilot cluster with CPU and GPU nodes as requested by the deployed workloads.

Standard

  1. In Cloud Shell, run the following command to create a Standard cluster:

     gcloud  
    container  
    clusters  
    create  
     CLUSTER_NAME 
      
     \ 
      
    --project = 
     PROJECT_ID 
      
     \ 
      
    --location = 
     CONTROL_PLANE_LOCATION 
      
     \ 
      
    --workload-pool = 
     PROJECT_ID 
    .svc.id.goog  
     \ 
      
    --release-channel = 
    rapid  
     \ 
      
    --num-nodes = 
     1 
      
     \ 
      
    --enable-managed-prometheus  
     \ 
      
    --monitoring = 
    SYSTEM,DCGM  
     \ 
      
    --gateway-api = 
    standard 
    

    Replace the following values:

    • PROJECT_ID : your Google Cloud project ID .
    • CONTROL_PLANE_LOCATION : the Compute Engine region of the control plane of your cluster. Provide a region that supports the accelerator type you want to use, for example, us-central1 for H100 GPU.
    • CLUSTER_NAME : the name of your cluster.

    The cluster creation might take several minutes.

  2. To create a node pool with the appropriate disk size for running Llama-3.1-8B-Instruct model, run the following command:

     gcloud  
    container  
    node-pools  
    create  
    gpupool  
     \ 
      
    --accelerator  
     type 
     = 
    nvidia-h100-80gb,count = 
     2 
    ,gpu-driver-version = 
    latest  
     \ 
      
    --project = 
     PROJECT_ID 
      
     \ 
      
    --location = 
     CONTROL_PLANE_LOCATION 
      
     \ 
      
    --node-locations = 
     CONTROL_PLANE_LOCATION 
    -a  
     \ 
      
    --cluster = 
     CLUSTER_NAME 
      
     \ 
      
    --machine-type = 
    a3-highgpu-2g  
     \ 
      
    --num-nodes = 
     1 
      
     \ 
      
    --disk-type = 
     "pd-standard" 
     
    

    GKE creates a single node pool containing a H100 GPU.

  1. To set up authorization to scrape metrics, create the inference-gateway-sa-metrics-reader-secret secret:

      kubectl apply -f - <<EOF 
     --- 
     apiVersion 
     : 
      
     rbac.authorization.k8s.io/v1 
     kind 
     : 
      
     ClusterRole 
     metadata 
     : 
      
     name 
     : 
      
     inference-gateway-metrics-reader 
     rules 
     : 
     - 
      
     nonResourceURLs 
     : 
      
     - 
      
     /metrics 
      
     verbs 
     : 
      
     - 
      
     get 
     --- 
     apiVersion 
     : 
      
     v1 
     kind 
     : 
      
     ServiceAccount 
     metadata 
     : 
      
     name 
     : 
      
     inference-gateway-sa-metrics-reader 
      
     namespace 
     : 
      
     default 
     --- 
     apiVersion 
     : 
      
     rbac.authorization.k8s.io/v1 
     kind 
     : 
      
     ClusterRoleBinding 
     metadata 
     : 
      
     name 
     : 
      
     inference-gateway-sa-metrics-reader-role-binding 
      
     namespace 
     : 
      
     default 
     subjects 
     : 
     - 
      
     kind 
     : 
      
     ServiceAccount 
      
     name 
     : 
      
     inference-gateway-sa-metrics-reader 
      
     namespace 
     : 
      
     default 
     roleRef 
     : 
      
     kind 
     : 
      
     ClusterRole 
      
     name 
     : 
      
     inference-gateway-metrics-reader 
      
     apiGroup 
     : 
      
     rbac.authorization.k8s.io 
     --- 
     apiVersion 
     : 
      
     v1 
     kind 
     : 
      
     Secret 
     metadata 
     : 
      
     name 
     : 
      
     inference-gateway-sa-metrics-reader-secret 
      
     namespace 
     : 
      
     default 
      
     annotations 
     : 
      
     kubernetes.io/service-account.name 
     : 
      
     inference-gateway-sa-metrics-reader 
     type 
     : 
      
     kubernetes.io/service-account-token 
     --- 
     apiVersion 
     : 
      
     rbac.authorization.k8s.io/v1 
     kind 
     : 
      
     ClusterRole 
     metadata 
     : 
      
     name 
     : 
      
     inference-gateway-sa-metrics-reader-secret-read 
     rules 
     : 
     - 
      
     resources 
     : 
      
     - 
      
     secrets 
      
     apiGroups 
     : 
      
     [ 
     "" 
     ] 
      
     verbs 
     : 
      
     [ 
     "get" 
     , 
      
     "list" 
     , 
      
     "watch" 
     ] 
      
     resourceNames 
     : 
      
     [ 
     "inference-gateway-sa-metrics-reader-secret" 
     ] 
     --- 
     apiVersion 
     : 
      
     rbac.authorization.k8s.io/v1 
     kind 
     : 
      
     ClusterRoleBinding 
     metadata 
     : 
      
     name 
     : 
      
     gmp-system:collector:inference-gateway-sa-metrics-reader-secret-read 
      
     namespace 
     : 
      
     default 
     roleRef 
     : 
      
     name 
     : 
      
     inference-gateway-sa-metrics-reader-secret-read 
      
     kind 
     : 
      
     ClusterRole 
      
     apiGroup 
     : 
      
     rbac.authorization.k8s.io 
     subjects 
     : 
     - 
      
     name 
     : 
      
     collector 
      
     namespace 
     : 
      
     gmp-system 
      
     kind 
     : 
      
     ServiceAccount 
     EOF 
     
    

Create a Kubernetes secret for Hugging Face credentials

In Cloud Shell, do the following:

  1. To communicate with your cluster, configure kubectl :

       
    gcloud  
    container  
    clusters  
    get-credentials  
     CLUSTER_NAME 
      
     \ 
      
    --location = 
     CONTROL_PLANE_LOCATION 
     
    

    Replace the following values:

    • CONTROL_PLANE_LOCATION : the Compute Engine region of the control plane of your cluster.
    • CLUSTER_NAME : the name of your cluster.
  2. Create a Kubernetes Secret that contains the Hugging Face token:

       
    kubectl  
    create  
    secret  
    generic  
     HF_SECRET 
      
     \ 
      
    --from-literal = 
     token 
     = 
     HF_TOKEN 
      
     \ 
      
    --dry-run = 
    client  
    -o  
    yaml  
     | 
      
    kubectl  
    apply  
    -f  
    - 
    

    Replace the following:

    • HF_TOKEN : the Hugging Face token you generated earlier.
    • HF_SECRET : the name for your Kubernetes secret. For example, hf-secret .

Install the InferenceModel and InferencePool CRDs

In this section, you install the necessary Custom Resource Definitions (CRDs) for GKE Inference Gateway.

CRDs extend the Kubernetes API. This lets you define new resource types. To use GKE Inference Gateway, install the InferencePool and InferenceModel CRDs in your GKE cluster by running the following command:

 kubectl  
apply  
-f  
https://github.com/kubernetes-sigs/gateway-api-inference-extension/releases/download/v0.3.0/manifests.yaml 

Deploy the model server

This example deploys a Llama3.1 model using a vLLM model server. The deployment is labeled as app:vllm-llama3-8b-instruct . This deployment also uses two LoRA adapters named food-review and cad-fabricator from Hugging Face. You can update this deployment with your own model server and model container, serving port, and deployment name. You can optionally configure LoRA adapters in the deployment, or deploy the base model.

  1. To deploy on a nvidia-h100-80gb accelerator type, save the following manifest as vllm-llama3-8b-instruct.yaml . This manifest defines a Kubernetes Deployment with your model and model server:

      apiVersion 
     : 
      
     apps/v1 
     kind 
     : 
      
     Deployment 
     metadata 
     : 
      
     name 
     : 
      
     vllm-llama3-8b-instruct 
     spec 
     : 
      
     replicas 
     : 
      
     3 
      
     selector 
     : 
      
     matchLabels 
     : 
      
     app 
     : 
      
     vllm-llama3-8b-instruct 
      
     template 
     : 
      
     metadata 
     : 
      
     labels 
     : 
      
     app 
     : 
      
     vllm-llama3-8b-instruct 
      
     spec 
     : 
      
     containers 
     : 
      
     - 
      
     name 
     : 
      
     vllm 
      
     image 
     : 
      
     "vllm/vllm-openai:latest" 
      
     imagePullPolicy 
     : 
      
     Always 
      
     command 
     : 
      
     [ 
     "python3" 
     , 
      
     "-m" 
     , 
      
     "vllm.entrypoints.openai.api_server" 
     ] 
      
     args 
     : 
      
     - 
      
     "--model" 
      
     - 
      
     "meta-llama/Llama-3.1-8B-Instruct" 
      
     - 
      
     "--tensor-parallel-size" 
      
     - 
      
     "1" 
      
     - 
      
     "--port" 
      
     - 
      
     "8000" 
      
     - 
      
     "--enable-lora" 
      
     - 
      
     "--max-loras" 
      
     - 
      
     "2" 
      
     - 
      
     "--max-cpu-loras" 
      
     - 
      
     "12" 
      
     env 
     : 
      
     # Enabling LoRA support temporarily disables automatic v1, we want to force it on 
      
     # until 0.8.3 vLLM is released. 
      
     - 
      
     name 
     : 
      
     VLLM_USE_V1 
      
     value 
     : 
      
     "1" 
      
     - 
      
     name 
     : 
      
     PORT 
      
     value 
     : 
      
     "8000" 
      
     - 
      
     name 
     : 
      
     HUGGING_FACE_HUB_TOKEN 
      
     valueFrom 
     : 
      
     secretKeyRef 
     : 
      
     name 
     : 
      
     hf-token 
      
     key 
     : 
      
     token 
      
     - 
      
     name 
     : 
      
     VLLM_ALLOW_RUNTIME_LORA_UPDATING 
      
     value 
     : 
      
     "true" 
      
     ports 
     : 
      
     - 
      
     containerPort 
     : 
      
     8000 
      
     name 
     : 
      
     http 
      
     protocol 
     : 
      
     TCP 
      
     lifecycle 
     : 
      
     preStop 
     : 
      
     # vLLM stops accepting connections when it receives SIGTERM, so we need to sleep 
      
     # to give upstream gateways a chance to take us out of rotation. The time we wait 
      
     # is dependent on the time it takes for all upstreams to completely remove us from 
      
     # rotation. Older or simpler load balancers might take upwards of 30s, but we expect 
      
     # our deployment to run behind a modern gateway like Envoy which is designed to 
      
     # probe for readiness aggressively. 
      
     sleep 
     : 
      
     # Upstream gateway probers for health should be set on a low period, such as 5s, 
      
     # and the shorter we can tighten that bound the faster that we release 
      
     # accelerators during controlled shutdowns. However, we should expect variance, 
      
     # as load balancers may have internal delays, and we don't want to drop requests 
      
     # normally, so we're often aiming to set this value to a p99 propagation latency 
      
     # of readiness -> load balancer taking backend out of rotation, not the average. 
      
     # 
      
     # This value is generally stable and must often be experimentally determined on 
      
     # for a given load balancer and health check period. We set the value here to 
      
     # the highest value we observe on a supported load balancer, and we recommend 
      
     # tuning this value down and verifying no requests are dropped. 
      
     # 
      
     # If this value is updated, be sure to update terminationGracePeriodSeconds. 
      
     # 
      
     seconds 
     : 
      
     30 
      
     # 
      
     # IMPORTANT: preStop.sleep is beta as of Kubernetes 1.30 - for older versions 
      
     # replace with this exec action. 
      
     #exec: 
      
     #  command: 
      
     #  - /usr/bin/sleep 
      
     #  - 30 
      
     livenessProbe 
     : 
      
     httpGet 
     : 
      
     path 
     : 
      
     /health 
      
     port 
     : 
      
     http 
      
     scheme 
     : 
      
     HTTP 
      
     # vLLM's health check is simple, so we can more aggressively probe it.  Liveness 
      
     # check endpoints should always be suitable for aggressive probing. 
      
     periodSeconds 
     : 
      
     1 
      
     successThreshold 
     : 
      
     1 
      
     # vLLM has a very simple health implementation, which means that any failure is 
      
     # likely significant. However, any liveness triggered restart requires the very 
      
     # large core model to be reloaded, and so we should bias towards ensuring the 
      
     # server is definitely unhealthy vs immediately restarting. Use 5 attempts as 
      
     # evidence of a serious problem. 
      
     failureThreshold 
     : 
      
     5 
      
     timeoutSeconds 
     : 
      
     1 
      
     readinessProbe 
     : 
      
     httpGet 
     : 
      
     path 
     : 
      
     /health 
      
     port 
     : 
      
     http 
      
     scheme 
     : 
      
     HTTP 
      
     # vLLM's health check is simple, so we can more aggressively probe it.  Readiness 
      
     # check endpoints should always be suitable for aggressive probing, but may be 
      
     # slightly more expensive than readiness probes. 
      
     periodSeconds 
     : 
      
     1 
      
     successThreshold 
     : 
      
     1 
      
     # vLLM has a very simple health implementation, which means that any failure is 
      
     # likely significant, 
      
     failureThreshold 
     : 
      
     1 
      
     timeoutSeconds 
     : 
      
     1 
      
     # We set a startup probe so that we don't begin directing traffic or checking 
      
     # liveness to this instance until the model is loaded. 
      
     startupProbe 
     : 
      
     # Failure threshold is when we believe startup will not happen at all, and is set 
      
     # to the maximum possible time we believe loading a model will take. In our 
      
     # default configuration we are downloading a model from HuggingFace, which may 
      
     # take a long time, then the model must load into the accelerator. We choose 
      
     # 10 minutes as a reasonable maximum startup time before giving up and attempting 
      
     # to restart the pod. 
      
     # 
      
     # IMPORTANT: If the core model takes more than 10 minutes to load, pods will crash 
      
     # loop forever. Be sure to set this appropriately. 
      
     failureThreshold 
     : 
      
     3600 
      
     # Set delay to start low so that if the base model changes to something smaller 
      
     # or an optimization is deployed, we don't wait unnecessarily. 
      
     initialDelaySeconds 
     : 
      
     2 
      
     # As a startup probe, this stops running and so we can more aggressively probe 
      
     # even a moderately complex startup - this is a very important workload. 
      
     periodSeconds 
     : 
      
     1 
      
     httpGet 
     : 
      
     # vLLM does not start the OpenAI server (and hence make /health available) 
      
     # until models are loaded. This may not be true for all model servers. 
      
     path 
     : 
      
     /health 
      
     port 
     : 
      
     http 
      
     scheme 
     : 
      
     HTTP 
      
     resources 
     : 
      
     limits 
     : 
      
     nvidia.com/gpu 
     : 
      
     1 
      
     requests 
     : 
      
     nvidia.com/gpu 
     : 
      
     1 
      
     volumeMounts 
     : 
      
     - 
      
     mountPath 
     : 
      
     /data 
      
     name 
     : 
      
     data 
      
     - 
      
     mountPath 
     : 
      
     /dev/shm 
      
     name 
     : 
      
     shm 
      
     - 
      
     name 
     : 
      
     adapters 
      
     mountPath 
     : 
      
     "/adapters" 
      
     initContainers 
     : 
      
     - 
      
     name 
     : 
      
     lora-adapter-syncer 
      
     tty 
     : 
      
     true 
      
     stdin 
     : 
      
     true 
      
     image 
     : 
      
     us-central1-docker.pkg.dev/k8s-staging-images/gateway-api-inference-extension/lora-syncer:main 
      
     restartPolicy 
     : 
      
     Always 
      
     imagePullPolicy 
     : 
      
     Always 
      
     env 
     : 
      
     - 
      
     name 
     : 
      
     DYNAMIC_LORA_ROLLOUT_CONFIG 
      
     value 
     : 
      
     "/config/configmap.yaml" 
      
     volumeMounts 
     : 
      
     # DO NOT USE subPath, dynamic configmap updates don't work on subPaths 
      
     - 
      
     name 
     : 
      
     config-volume 
      
     mountPath 
     : 
      
     /config 
      
     restartPolicy 
     : 
      
     Always 
      
     # vLLM allows VLLM_PORT to be specified as an environment variable, but a user might 
      
     # create a 'vllm' service in their namespace. That auto-injects VLLM_PORT in docker 
      
     # compatible form as `tcp://<IP>:<PORT>` instead of the numeric value vLLM accepts 
      
     # causing CrashLoopBackoff. Set service environment injection off by default. 
      
     enableServiceLinks 
     : 
      
     false 
      
     # Generally, the termination grace period needs to last longer than the slowest request 
      
     # we expect to serve plus any extra time spent waiting for load balancers to take the 
      
     # model server out of rotation. 
      
     # 
      
     # An easy starting point is the p99 or max request latency measured for your workload, 
      
     # although LLM request latencies vary significantly if clients send longer inputs or 
      
     # trigger longer outputs. Since steady state p99 will be higher than the latency 
      
     # to drain a server, you may wish to slightly this value either experimentally or 
      
     # via the calculation below. 
      
     # 
      
     # For most models you can derive an upper bound for the maximum drain latency as 
      
     # follows: 
      
     # 
      
     #   1. Identify the maximum context length the model was trained on, or the maximum 
      
     #      allowed length of output tokens configured on vLLM (llama2-7b was trained to 
      
     #      4k context length, while llama3-8b was trained to 128k). 
      
     #   2. Output tokens are the more compute intensive to calculate and the accelerator 
      
     #      will have a maximum concurrency (batch size) - the time per output token at 
      
     #      maximum batch with no prompt tokens being processed is the slowest an output 
      
     #      token can be generated (for this model it would be about 100ms TPOT at a max 
      
     #      batch size around 50) 
      
     #   3. Calculate the worst case request duration if a request starts immediately 
      
     #      before the server stops accepting new connections - generally when it receives 
      
     #      SIGTERM (for this model that is about 4096 / 10 ~ 40s) 
      
     #   4. If there are any requests generating prompt tokens that will delay when those 
      
     #      output tokens start, and prompt token generation is roughly 6x faster than 
      
     #      compute-bound output token generation, so add 20% to the time from above (40s + 
      
     #      16s ~ 55s) 
      
     # 
      
     # Thus we think it will take us at worst about 55s to complete the longest possible 
      
     # request the model is likely to receive at maximum concurrency (highest latency) 
      
     # once requests stop being sent. 
      
     # 
      
     # NOTE: This number will be lower than steady state p99 latency since we stop       receiving 
      
     #       new requests which require continuous prompt token computation. 
      
     # NOTE: The max timeout for backend connections from gateway to model servers should 
      
     #       be configured based on steady state p99 latency, not drain p99 latency 
      
     # 
      
     #   5. Add the time the pod takes in its preStop hook to allow the load balancers have 
      
     #      stopped sending us new requests (55s + 30s ~ 85s) 
      
     # 
      
     # Because the termination grace period controls when the Kubelet forcibly terminates a 
      
     # stuck or hung process (a possibility due to a GPU crash), there is operational safety 
      
     # in keeping the value roughly proportional to the time to finish serving. There is also 
      
     # value in adding a bit of extra time to deal with unexpectedly long workloads. 
      
     # 
      
     #   6. Add a 50% safety buffer to this time since the operational impact should be low 
      
     #      (85s * 1.5 ~ 130s) 
      
     # 
      
     # One additional source of drain latency is that some workloads may run close to 
      
     # saturation and have queued requests on each server. Since traffic in excess of the 
      
     # max sustainable QPS will result in timeouts as the queues grow, we assume that failure 
      
     # to drain in time due to excess queues at the time of shutdown is an expected failure 
      
     # mode of server overload. If your workload occasionally experiences high queue depths 
      
     # due to periodic traffic, consider increasing the safety margin above to account for 
      
     # time to drain queued requests. 
      
     terminationGracePeriodSeconds 
     : 
      
     130 
      
     nodeSelector 
     : 
      
     cloud.google.com/gke-accelerator 
     : 
      
     "nvidia-h100-80gb" 
      
     volumes 
     : 
      
     - 
      
     name 
     : 
      
     data 
      
     emptyDir 
     : 
      
     {} 
      
     - 
      
     name 
     : 
      
     shm 
      
     emptyDir 
     : 
      
     medium 
     : 
      
     Memory 
      
     - 
      
     name 
     : 
      
     adapters 
      
     emptyDir 
     : 
      
     {} 
      
     - 
      
     name 
     : 
      
     config-volume 
      
     configMap 
     : 
      
     name 
     : 
      
     vllm-llama3-8b-adapters 
     --- 
     apiVersion 
     : 
      
     v1 
     kind 
     : 
      
     ConfigMap 
     metadata 
     : 
      
     name 
     : 
      
     vllm-llama3-8b-adapters 
     data 
     : 
      
     configmap.yaml 
     : 
      
     | 
      
     vLLMLoRAConfig: 
      
     name: vllm-llama3.1-8b-instruct 
      
     port: 8000 
      
     defaultBaseModel: meta-llama/Llama-3.1-8B-Instruct 
      
     ensureExist: 
      
     models: 
      
     - id: food-review 
      
     source: Kawon/llama3.1-food-finetune_v14_r8 
      
     - id: cad-fabricator 
      
     source: redcathode/fabricator 
     --- 
     kind 
     : 
      
     HealthCheckPolicy 
     apiVersion 
     : 
      
     networking.gke.io/v1 
     metadata 
     : 
      
     name 
     : 
      
     health-check-policy 
      
     namespace 
     : 
      
     default 
     spec 
     : 
      
     targetRef 
     : 
      
     group 
     : 
      
     "inference.networking.x-k8s.io" 
      
     kind 
     : 
      
     InferencePool 
      
     name 
     : 
      
     vllm-llama3-8b-instruct 
      
     default 
     : 
      
     config 
     : 
      
     type 
     : 
      
     HTTP 
      
     httpHealthCheck 
     : 
      
     requestPath 
     : 
      
     /health 
      
     port 
     : 
      
     8000 
     
    
  2. Apply the manifest to your cluster:

     kubectl  
    apply  
    -f  
    vllm-llama3-8b-instruct.yaml 
    

Create an InferencePool resource

The InferencePool Kubernetes custom resource defines a group of Pods with a common base LLM and compute configuration.

The InferencePool custom resource includes the following key fields:

  • selector : specifies which Pods belong to this pool. The labels in this selector must exactly match the labels applied to your model server Pods.
  • targetPort : defines the ports used by the model server within the Pods.

The InferencePool resource enables GKE Inference Gateway to route traffic to your model server Pods.

To create an InferencePool using Helm, perform the following steps:

 helm  
install  
vllm-llama3-8b-instruct  
 \ 
  
--set  
inferencePool.modelServers.matchLabels.app = 
vllm-llama3-8b-instruct  
 \ 
  
--set  
provider.name = 
gke  
 \ 
  
--set  
healthCheckPolicy.create = 
 false 
  
 \ 
  
--version  
v0.3.0  
 \ 
  
oci://registry.k8s.io/gateway-api-inference-extension/charts/inferencepool 

Change the following field to match your Deployment:

  • inferencePool.modelServers.matchLabels.app : the key of the label used to select your model server Pods.

This command creates an InferencePool object that logically represents your model server deployment and references the model endpoint services within the Pods that the Selector selects.

Create an InferenceModel resource with a serving criticality

The InferenceModel Kubernetes custom resource defines a specific model, including LoRA-tuned models, and its serving criticality.

The InferenceModel custom resource includes the following key fields:

  • modelName : specifies the name of the base model or LoRA adapter.
  • Criticality : specifies the serving criticality of the model.
  • poolRef : references the InferencePool that the model is served on.

The InferenceModel enables the GKE Inference Gateway to route traffic to your model server Pods based on the model name and criticality.

To create an InferenceModel , perform the following steps:

  1. Save the following sample manifest as inferencemodel.yaml :

      apiVersion 
     : 
      
     inference.networking.x-k8s.io/v1alpha2 
     kind 
     : 
      
     InferenceModel 
     metadata 
     : 
      
     name 
     : 
      
     inferencemodel-sample 
     spec 
     : 
      
     modelName 
     : 
      
      MODEL_NAME 
     
      
     criticality 
     : 
      
      CRITICALITY 
     
      
     poolRef 
     : 
      
     name 
     : 
      
      INFERENCE_POOL_NAME 
     
     
    

    Replace the following:

    • MODEL_NAME : the name of your base model or LoRA adapter. For example, food-review .
    • CRITICALITY : the chosen serving criticality. Choose from Critical , Standard , or Sheddable . For example, Standard .
    • INFERENCE_POOL_NAME : the name of the InferencePool you created in the previous step. For example, vllm-llama3-8b-instruct .
  2. Apply the sample manifest to your cluster:

     kubectl  
    apply  
    -f  
    inferencemodel.yaml 
    

The following example creates an InferenceModel object that configures the food-review LoRA model on the vllm-llama3-8b-instruct InferencePool with a Standard serving criticality. The InferenceModel object also configures the base model to be served with a Critical priority level.

  apiVersion 
 : 
  
 inference.networking.x-k8s.io/v1alpha2 
 kind 
 : 
  
 InferenceModel 
 metadata 
 : 
  
 name 
 : 
  
 food-review 
 spec 
 : 
  
 modelName 
 : 
  
 food-review 
  
 criticality 
 : 
  
 Standard 
  
 poolRef 
 : 
  
 name 
 : 
  
 vllm-llama3-8b-instruct 
  
 targetModels 
 : 
  
 - 
  
 name 
 : 
  
 food-review 
  
 weight 
 : 
  
 100 
 --- 
 apiVersion 
 : 
  
 inference.networking.x-k8s.io/v1alpha2 
 kind 
 : 
  
 InferenceModel 
 metadata 
 : 
  
 name 
 : 
  
 llama3-base-model 
 spec 
 : 
  
 modelName 
 : 
  
 meta-llama/Llama-3.1-8B-Instruct 
  
 criticality 
 : 
  
 Critical 
  
 poolRef 
 : 
  
 name 
 : 
  
 vllm-llama3-8b-instruct 
 

Create the Gateway

The Gateway resource acts as the entry point for external traffic into your Kubernetes cluster. It defines the listeners that accept incoming connections.

GKE Inference Gateway supports the gke-l7-rilb and gke-l7-regional-external-managed Gateway Class. For more information, see the GKE documentation on Gateway Classes .

To create a Gateway, perform the following steps:

  1. Save the following sample manifest as gateway.yaml :

      apiVersion 
     : 
      
     gateway.networking.k8s.io/v1 
     kind 
     : 
      
     Gateway 
     metadata 
     : 
      
     name 
     : 
      
      GATEWAY_NAME 
     
     spec 
     : 
      
     gatewayClassName 
     : 
      
     gke-l7-regional-external-managed 
      
     listeners 
     : 
      
     - 
      
     protocol 
     : 
      
     HTTP 
      
     # Or HTTPS for production 
      
     port 
     : 
      
     80 
      
     # Or 443 for HTTPS 
      
     name 
     : 
      
     http 
     
    

    Replace GATEWAY_NAME with a unique name for your Gateway resource. For example, inference-gateway .

  2. Apply the manifest to your cluster:

     kubectl  
    apply  
    -f  
    gateway.yaml 
    

Create the HTTPRoute resource

In this section, you create an HTTPRoute resource to define how the Gateway routes incoming HTTP requests to your InferencePool .

The HTTPRoute resource defines how the GKE Gateway routes incoming HTTP requests to backend services, which is your InferencePool . It specifies matching rules (for example, headers, or paths) and the backend to which traffic should be forwarded.

To create an HTTPRoute, perform the following steps:

  1. Save the following sample manifest as httproute.yaml :

      apiVersion 
     : 
      
     gateway.networking.k8s.io/v1 
     kind 
     : 
      
     HTTPRoute 
     metadata 
     : 
      
     name 
     : 
      
      HTTPROUTE_NAME 
     
     spec 
     : 
      
     parentRefs 
     : 
      
     - 
      
     name 
     : 
      
      GATEWAY_NAME 
     
      
     rules 
     : 
      
     - 
      
     matches 
     : 
      
     - 
      
     path 
     : 
      
     type 
     : 
      
     PathPrefix 
      
     value 
     : 
      
      PATH_PREFIX 
     
      
     backendRefs 
     : 
      
     - 
      
     name 
     : 
      
      INFERENCE_POOL_NAME 
     
      
     group 
     : 
      
     inference.networking.x-k8s.io 
      
     kind 
     : 
      
     InferencePool 
     
    

    Replace the following:

    • HTTPROUTE_NAME : a unique name for your HTTPRoute resource. For example, my-route .
    • GATEWAY_NAME : the name of the Gateway resource that you created. For example, inference-gateway .
    • PATH_PREFIX : the path prefix that you use to match incoming requests. For example, / to match all.
    • INFERENCE_POOL_NAME : the name of the InferencePool resource that you want to route traffic to. For example, vllm-llama3-8b-instruct .
  2. Apply the manifest to your cluster:

     kubectl  
    apply  
    -f  
    httproute.yaml 
    

Send an inference request

After you have configured GKE Inference Gateway, you can send inference requests to your deployed model.

To send inference requests, perform the following steps:

  • Retrieve the Gateway endpoint.
  • Construct a properly formatted JSON request.
  • Use curl to send the request to the /v1/completions endpoint.

This lets you generate text based on your input prompt and specified parameters.

  1. To get the Gateway endpoint, run the following command:

      IP 
     = 
     $( 
    kubectl  
    get  
    gateway/ GATEWAY_NAME 
      
    -o  
     jsonpath 
     = 
     '{.status.addresses[0].value}' 
     ) 
     PORT 
     = 
     PORT_NUMBER 
      
     # Use 443 for HTTPS, or 80 for HTTP 
     
    

    Replace the following:

    • GATEWAY_NAME : the name of your Gateway resource.
    • PORT_NUMBER : the port number you configured in the Gateway.
  2. To send a request to the /v1/completions endpoint using curl , run the following command:

     curl  
    -i  
    -X  
    POST  
    https:// ${ 
     IP 
     } 
    : ${ 
     PORT 
     } 
    /v1/completions  
     \ 
    -H  
     'Content-Type: application/json' 
      
     \ 
    -H  
     'Authorization: Bearer $(gcloud auth print-access-token)' 
      
     \ 
    -d  
     '{ 
     "model": " MODEL_NAME 
    ", 
     "prompt": " PROMPT_TEXT 
    ", 
     "max_tokens": MAX_TOKENS 
    , 
     "temperature": " TEMPERATURE 
    " 
     }' 
     
    

    Replace the following:

    • MODEL_NAME : the name of the model or LoRA adapter to use.
    • PROMPT_TEXT : the input prompt for the model.
    • MAX_TOKENS : the maximum number of tokens to generate in the response.
    • TEMPERATURE : controls the randomness of the output. Use the value 0 for deterministic output, or a higher number for more creative output.

Be aware of the following behaviors:

  • Request body: the request body can include additional parameters like stop and top_p . Refer to the OpenAI API specification for a complete list of options.
  • Error handling: implement proper error handling in your client code to handle potential errors in the response. For example, check the HTTP status code in the curl response. A non-200 status code generally indicates an error.
  • Authentication and authorization: for production deployments, secure your API endpoint with authentication and authorization mechanisms. Include the appropriate headers (for example, Authorization ) in your requests.

Configure observability for your Inference Gateway

GKE Inference Gateway provides observability into the health, performance, and behavior of your inference workloads. This helps you to identify and resolve issues, optimize resource utilization, and ensure the reliability of your applications. You can view these observability metrics in Cloud Monitoring through the Metrics Explorer .

To configure observability for GKE Inference Gateway, see Configure observability .

Delete the deployed resources

To avoid incurring charges to your Google Cloud account for the resources that you created from this guide, run the following command:

 gcloud  
container  
clusters  
delete  
 CLUSTER_NAME 
  
 \ 
  
--location = 
 CONTROL_PLANE_LOCATION 
 

Replace the following values:

  • CONTROL_PLANE_LOCATION : the Compute Engine region of the control plane of your cluster.
  • CLUSTER_NAME : the name of your cluster.

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