Traefik as Edge Router for Kubernetes-hosted LLMs

Question

Pulumi · Accepted Answer

To deploy Traefik as an edge router for Kubernetes-hosted Low Latency Microservices (LLMs), we can use Pulumi to automate the creation and configuration of the necessary Kubernetes resources. Traefik is a modern HTTP reverse proxy and load balancer that makes deploying microservices easy.

Here’s a step-by-step explanation followed by a Pulumi Python program:

1. **Namespace**: We'll create a dedicated Kubernetes namespace for Traefik to keep its resources isolated from other services.

2. **ServiceAccount**: Traefik requires a service account with the necessary permissions to watch and manage resources in the Kubernetes cluster.

3. **ClusterRole** and **ClusterRoleBinding**: These will give Traefik the permissions needed to function as an ingress controller, allowing it to observe changes to ingress resources and make necessary adjustments.

4. **Deployment**: This is where we define the Traefik deployment, specifying the Docker image to use and the desired number of replicas.

5. **Service**: We need a service to expose Traefik to the outside world. This could be a `LoadBalancer` service if you’re on a cloud provider that supports it, or a `NodePort` service if you’re not.

Please note that for this program, you will need to have `pulumi` and `pulumi_kubernetes` packages installed and have access to a Kubernetes cluster where Pulumi can create resources.

Let's start with the Pulumi program that accomplishes the above steps:

```python
import pulumi
from pulumi_kubernetes.apps.v1 import Deployment
from pulumi_kubernetes.core.v1 import ServiceAccount, Service
from pulumi_kubernetes.rbac.v1 import ClusterRole, ClusterRoleBinding
from pulumi_kubernetes import Provider
from pulumi_kubernetes.meta.v1 import Namespace

# Create a new Kubernetes provider instance using the current context
k8s_provider = Provider("k8s_provider")

# Create a namespace for Traefik
ns = Namespace("traefik-ns",
    metadata={"name": "traefik"},
    opts=pulumi.ResourceOptions(provider=k8s_provider))

# Create a service account for Traefik within the namespace
service_account = ServiceAccount("traefik-service-account",
    metadata={
        "namespace": ns.metadata["name"]
    },
    opts=pulumi.ResourceOptions(provider=k8s_provider))

# Create the ClusterRole necessary for Traefik
cluster_role = ClusterRole("traefik-cluster-role",
    rules=[{
        "apiGroups": ["", "extensions", "apps"],
        "resources": ["services", "endpoints", "pods", "ingresses"],
        "verbs": ["get", "list", "watch"]
    }],
    opts=pulumi.ResourceOptions(provider=k8s_provider))

# Bind the service account to the ClusterRole
cluster_role_binding = ClusterRoleBinding("traefik-cluster-role-binding",
    subjects=[{
        "kind": "ServiceAccount",
        "name": service_account.metadata["name"],
        "namespace": ns.metadata["name"],
    }],
    role_ref={
        "kind": "ClusterRole",
        "name": cluster_role.metadata["name"],
        "apiGroup": "rbac.authorization.k8s.io"
    },
    opts=pulumi.ResourceOptions(provider=k8s_provider))

# Create the Traefik deployment
deployment = Deployment("traefik-deployment",
    spec={
        "selector": {"matchLabels": {"app": "traefik"}},
        "replicas": 2,
        "template": {
            "metadata": {"labels": {"app": "traefik"}},
            "spec": {
                "serviceAccountName": service_account.metadata["name"],
                "containers": [{
                    "name": "traefik",
                    "image": "traefik:v2.3",
                    "args": [
                        "--api.insecure=true",
                        "--accesslog",
                        "--entrypoints.web.Address=:80",
                        "--entrypoints.websecure.Address=:443",
                        "--providers.kubernetescrd"
                    ],
                    "ports": [
                        {"name": "web", "containerPort": 80},
                        {"name": "websecure", "containerPort": 443},
                        {"name": "admin", "containerPort": 8080}
                    ]
                }]
            }
        }
    },
    opts=pulumi.ResourceOptions(provider=k8s_provider))

# Create a service to expose the Traefik deployment
service = Service("traefik-service",
    spec={
        "type": "LoadBalancer",
        "ports": [
            {"name": "web", "port": 80},
            {"name": "websecure", "port": 443},
            {"name": "admin", "port": 8080}
        ],
        "selector": {"app": "traefik"}
    },
    metadata={"namespace": ns.metadata["name"]},
    opts=pulumi.ResourceOptions(provider=k8s_provider))

# Export the Traefik Service endpoint to access the Traefik dashboard
pulumi.export('traefik_service_endpoint', pulumi.Output.concat("http://", service.status["load_balancer"]["ingress"][0]["ip"]))
```

This program sets up Traefik in a Kubernetes cluster and exposes it so that it can receive traffic. The Traefik deployment is configured to run 2 replicas for redundancy. The service account, cluster role, and role binding grant the necessary permissions to the Traefik pods to manage ingress resources in the cluster.

Once you deploy this program with Pulumi (using `pulumi up`), it will create all of these resources in your Kubernetes cluster. You can then access the Traefik dashboard using the service endpoint URL exported at the end of the program.