Using kubernetes monitoring.coreos.com with traefik

Question

Pulumi · Accepted Answer

To integrate Kubernetes with CoreOS monitoring (via Prometheus Operator) and Traefik, we will create a program using Pulumi and the Kubernetes SDK. This setup will enable you to monitor your Kubernetes cluster workloads and use Traefik as an Ingress controller.

Our Pulumi program will perform the following actions:
1. Deploy the Prometheus Operator, which provides Kubernetes native deployment and management of Prometheus and related monitoring components.
2. Set up a ServiceMonitor, which is a custom resource defined by the Prometheus Operator to specify how groups of Kubernetes services should be monitored.
3. Deploy Traefik as an Ingress controller, which allows you to expose your services to the internet and route traffic accordingly.

Let's first explain the components that will be used:
- **Prometheus Operator**: Automates the configuration of a Prometheus-based monitoring stack.
- **ServiceMonitor**: A custom resource used by Prometheus Operator to configure how Prometheus instances should discover and scrape metrics from Kubernetes services.
- **Traefik**: A modern HTTP reverse proxy and load balancer that makes deploying microservices easy.

Now, let's write the Pulumi program in TypeScript.

```typescript
import * as k8s from '@pulumi/kubernetes';

// Create a namespace for our monitoring components
const monitoringNamespace = new k8s.core.v1.Namespace('monitoring-namespace', {
    metadata: {
        name: 'monitoring',
    },
});

// Deploy the Prometheus Operator
const prometheusOperator = new k8s.helm.v3.Chart('prometheus-operator', {
    namespace: monitoringNamespace.metadata.name,
    chart: 'kube-prometheus-stack',
    fetchOpts: {
        repo: 'https://prometheus-community.github.io/helm-charts',
    },
}, { dependsOn: monitoringNamespace });

// Deploy Traefik as an Ingress controller
const traefik = new k8s.helm.v3.Chart('traefik', {
    namespace: monitoringNamespace.metadata.name,
    chart: 'traefik',
    fetchOpts: {
        repo: 'https://helm.traefik.io/traefik',
    },
    values: {
        service: {
            annotations: {
                // Depending on your cloud provider, you might need other annotations
                // For example, on AWS:
                // "service.beta.kubernetes.io/aws-load-balancer-type": "nlb"
            },
        },
    },
}, { dependsOn: monitoringNamespace });

// The Prometheus Operator automatically creates a ServiceMonitor CRD.
// We can define a ServiceMonitor to monitor services.
const traefikServiceMonitor = new k8s.apiextensions.CustomResource('traefik-service-monitor', {
    apiVersion: 'monitoring.coreos.com/v1',
    kind: 'ServiceMonitor',
    metadata: {
        namespace: monitoringNamespace.metadata.name,
        name: 'traefik',
        labels: {
            'release': 'prometheus-operator',
        },
    },
    spec: {
        selector: {
            matchLabels: {
                // Use the labels from your Traefik service here
            },
        },
        namespaceSelector: {
            matchNames: [monitoringNamespace.metadata.name],
        },
        endpoints: [{
            port: 'web', // The name of the Traefik service port to scrape for metrics
        }],
    },
}, { dependsOn: [prometheusOperator, traefik] });

// Export the namespace name and Traefik load balancer endpoint
export const monitoringNamespaceName = monitoringNamespace.metadata.name;
export const traefikLoadBalancerEndpoint = traefik.getResource('v1/Service', 'traefik', 'traefik').status.loadBalancer.ingress[0].hostname;
```

Explanation of the code:
- We create a namespace named `monitoring` to keep our monitoring-related resources organized.
- We deploy the Prometheus Operator using the `kube-prometheus-stack` Helm chart, ensuring that it's deployed within the `monitoring` namespace.
- We deploy Traefik using its official Helm chart and provide its configurations. Depending on your cloud setup, you may need to add additional service annotations.
- We then define a ServiceMonitor for Traefik. This `ServiceMonitor` tells Prometheus to scrape metrics from the Traefik service.
- Finally, we export the names of the namespace and the Traefik Ingress endpoint for external reference.

To deploy this setup, you'll need to have Pulumi configured with access to your Kubernetes cluster. Once that's set up, running `pulumi up` will apply this configuration to your cluster.

Keep in mind that monitoring configurations and requirements may vary depending on your specific use case and deployment environment. This code sets up a basic integration that should work in most cases but may need to be adjusted for more complex scenarios.