Decoupled Model Serving on Kubernetes with FluxCD

Question

Pulumi · Accepted Answer

Sure, I can help you set up a decoupled model serving infrastructure on Kubernetes using FluxCD with Pulumi in Python.

To accomplish this goal, we will perform the following steps:

1. **Provision a Kubernetes cluster**: This will be the environment where our model-serving application will run. Depending on your preference and the cloud provider you are using, you may already have a cluster, or we'll need to create one using Pulumi's Kubernetes provider.

2. **Install FluxCD on the Kubernetes cluster**: FluxCD is a tool that allows you to manage your Kubernetes infrastructure and applications through declarative configuration files stored in a Git repository. It will watch for changes in this repository and apply the changes to the cluster. We can automate this with Pulumi using the `flux.FluxBootstrapGit` resource.

3. **Deploy model-serving components**: Finally, we will define the Kubernetes manifests required for model serving (e.g., Deployments, Services) and create a Git repository where FluxCD can watch for changes. This will typically involve setting up a system such as Seldon Core or NVIDIA Triton Inference Server, which are both popular for serving machine learning models.

Here's an example of how you might set this up using Pulumi and Python. Note that this is a simplified explanation and code block for the purpose of demonstration, and real-world applications might require more configuration and handling of edge cases.

```python
import pulumi
import pulumi_kubernetes as k8s
import pulumi_flux as flux

# Step 1: Provision a Kubernetes cluster (this might be different based on your cloud provider)
# Assuming you have a cluster ready, you will be working with the kubeconfig of that cluster

# Step 2: Install FluxCD in the Kubernetes cluster
# We will be using the flux.FluxBootstrapGit resource from the Pulumi Registry Results provided
flux_operator = flux.FluxBootstrapGit("flux-operator",
                                      version="1.0.1",
                                      interval="1m",
                                      logLevel="info",
                                      namespace="flux-system",
                                      components=["source-controller", "kustomize-controller"],
                                      secretName="flux-git-deploy",
                                      clusterDomain="cluster.local",
                                      watchAllNamespaces=True,
                                      path="./clusters/my-cluster")

# Step 3: Deploy additional resources for model-serving
# This is an example and will need to be adapted to the specifics of your model-serving app.
# In a real-world scenario, you would define your model-serving components here.
# For example, you could define a Deployment for a Seldon Core inference graph.

# Sample Deployment object definition
model_serving_deployment = {
    "apiVersion": "apps/v1",
    "kind": "Deployment",
    "metadata": {
        "name": "model-serving-deployment"
    },
    "spec": {
        "replicas": 3,
        "selector": {
            "matchLabels": {
                "app": "model-serving"
            }
        },
        "template": {
            "metadata": {
                "labels": {
                    "app": "model-serving"
                }
            },
            "spec": {
                "containers": [{
                    "name": "model",
                    "image": "your-model-serving-image",
                    # Define ports, environment variables, resources, etc.
                }]
            }
        }
    }
}

# Define the Kubernetes resources with Pulumi
app_deployment = k8s.yaml.ConfigGroup("model-serving-deployment",
                                      resource_prefix="model-serving",
                                      files=[model_serving_deployment])

# Export the FluxCD operator Git repository URL
pulumi.export("git_repository_url", flux_operator.url)
```

In this code:

- We provision a Kubernetes cluster (this step is assumed to be completed outside this snippet).
- We install FluxCD using `flux.FluxBootstrapGit`. This resource from Pulumi's library sets up FluxCD in our Kubernetes cluster, pointing to a Git repository that will hold our infrastructure and application definitions.
- We define a model-serving deployment (as a dictionary, which is then passed to `k8s.yaml.ConfigGroup` to be applied). This should be replaced with your actual model-serving deployment configuration.
- We export the URL of the Git repository that FluxCD will monitor for changes.

Remember that this is a high-level example, and you will need to adjust it according to your exact requirements, including setting up the Git repository, defining the appropriate service configurations, and tailoring the model-serving deployment specifications to match your application's needs.