Managing VictoriaMetrics scrape configurations with custom resources

Question

Pulumi · Accepted Answer

To manage VictoriaMetrics scrape configurations with custom resources in Kubernetes, we will define a Custom Resource Definition (CRD) that represents the scrape configurations. This will allow you to create, update, and delete scrape configurations using Kubernetes API just like any other built-in resources.

Below is an example of how you might define a custom resource in Pulumi using TypeScript. This example assumes you are familiar with Kubernetes concepts such as CRDs and you have the necessary permissions to create CRDs in your Kubernetes cluster.

First, we will define a CRD for a VictoriaMetrics scrape configuration. We will create a simple CRD with the minimum required fields for demonstrating the concept. It will include the `group`, `versions`, and `scope` which are mandatory fields for defining a CRD, as well as a `kind` which categorizes the custom resource, and `plural` specifying the plural name of the custom resource.

In this example, we name our custom resource 'VMScrapeConfig' (short for VictoriaMetrics Scrape Configuration) and define a property `scrapeConfig` that stores the configuration details.

Here's the code for setting up the CRD:

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

const vmScrapeConfigCRD = new k8s.apiextensions.v1.CustomResourceDefinition("vmScrapeConfigCrd", {
    metadata: { name: "vmscrapeconfigs.metrics.example.com" },
    spec: {
        group: "metrics.example.com",
        versions: [{
            name: "v1",
            served: true,
            storage: true,
            schema: {
                openAPIV3Schema: {
                    type: "object",
                    properties: {
                        spec: {
                            type: "object",
                            properties: {
                                scrapeConfig: {
                                    // Define the structure of your scrape configuration according to your requirements.
                                    // Example structure shown below, but this would vary according to how you want to
                                    // define the scrape configuration for VictoriaMetrics.
                                    type: "object",
                                    properties: {
                                        jobName: { type: "string" },
                                        staticConfigs: {
                                            type: "array",
                                            items: {
                                                type: "object",
                                                properties: {
                                                    targets: {
                                                        type: "array",
                                                        items: { type: "string" }
                                                    },
                                                    labels: {
                                                        type: "object",
                                                        additionalProperties: { type: "string" }
                                                    }
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }],
        scope: "Namespaced",
        names: {
            plural: "vmscrapeconfigs",
            singular: "vmscrapeconfig",
            kind: "VMScrapeConfig",
            shortNames: ["vmsc"]
        }
    }
});

// Now that we have defined the CRD, we can create instances of this custom resource.
const exampleScrapeConfig = new k8s.apiextensions.CustomResource("exampleScrapeConfig", {
    apiVersion: "metrics.example.com/v1",
    kind: "VMScrapeConfig",
    metadata: {
        namespace: "default",
        name: "example-scrape-config",
    },
    spec: {
        scrapeConfig: {
            jobName: "my-app",
            staticConfigs: [{
                targets: ["my-app-service:80"],
                labels: {
                    "service": "my-app",
                    "environment": "production"
                }
            }]
        }
    }
}, { dependsOn: [vmScrapeConfigCRD] });

export const vmScrapeConfigName = vmScrapeConfigCRD.metadata.name;
export const exampleScrapeConfigName = exampleScrapeConfig.metadata.name;
```

This Pulumi program does the following:
* Defines a CRD for VictoriaMetrics scrape configurations with a `scrapeConfig` property.
* Creates an instance of this custom resource named `exampleScrapeConfig` with a sample scrape configuration.
* Exports the names of the CRD and the custom resource instance for easy reference.

Before you run this program, ensure you have the Pulumi CLI installed and are authenticated with a Kubernetes cluster where you have permission to create CRD resources.

After defining and creating CRDs, you can manage your scrape configurations by applying changes to custom resources and the Kubernetes API will ensure to reconcile the state accordingly. This declarative approach is the essence of Kubernetes - you define the desired state of your resources and let Kubernetes handle the convergence.

Remember that you'll need to have Pulumi installed and configured for your Kubernetes cluster to run this program. Once you apply it with Pulumi, the CRD and the custom resource instance will be created in your cluster.