Using kubernetes opentelemetry.io with cronjobber.hidde.co

Question

Pulumi · Accepted Answer

If you're looking to instrument Kubernetes cron jobs with OpenTelemetry and manage them using the CronJobber tool, you're dealing with a couple of different technologies that integrate to improve observability and scheduling in a Kubernetes cluster.

Here's an overview of the concepts you'll be working with:

- **Kubernetes Cron Jobs**: These are jobs in a Kubernetes cluster that run on a time-based schedule, which is specified with the Cron format. They are useful for creating recurring tasks like backups, reports, and sending emails.

- **OpenTelemetry.io**: This is an observability framework for cloud-native software. It provides a single set of APIs, libraries, agents, and instrumentation to capture distributed traces and metrics from your applications.

- **CronJobber**: It is an open-source tool that extends the functionality of Kubernetes CronJobs by supporting time zones and daylight saving time changes.

In Pulumi, to create Kubernetes cron jobs, you'd typically use the `@pulumi/kubernetes` package. For CronJobber functionality, which extends Kubernetes cron jobs, you'd look to see if there's a Custom Resource Definition (CRD) that you could apply to your cluster, and then use that CRD with Pulumi. However, since the registry results don't show a direct resource for CronJobber, you would likely need to manually apply CronJobber's CRD to your cluster out of band or use Pulumi to apply that CRD YAML if you have it.

OpenTelemetry instrumentation would typically be handled within the application code or by deploying OpenTelemetry agents onto your cluster. So, you'd look for Kubernetes DaemonSets or Deployments related to OpenTelemetry and ensure your cron jobs export the necessary telemetry data.

While a Pulumi TypeScript program can handle the creation of Kubernetes resources, integrating OpenTelemetry within those resources (such as a cron job) can vary depending on how CronJobber and OpenTelemetry are set up in your cluster.

Here's a basic TypeScript Pulumi program to create a simple Kubernetes `CronJob`. But note that integrating OpenTelemetry and CronJobber specifics will depend on available CRDs, configurations, and your application code:

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

const namespace = "default"; // Ensure this is the namespace you want to use

// A simple example of a Kubernetes CronJob resource
const cronJob = new k8s.batch.v1beta1.CronJob("myCronJob", {
    metadata: {
        namespace: namespace,
    },
    spec: {
        schedule: "*/5 * * * *", // Execute every 5 minutes
        jobTemplate: {
            spec: {
                template: {
                    spec: {
                        restartPolicy: "OnFailure", // Job Restart policy
                        containers: [
                            {
                                name: "mycontainer",
                                image: "myimage", // Replace with the real container image
                                // Here you may set up environment variables or volume mounts necessary
                                // for OpenTelemetry instrumentation
                                env: [
                                    {
                                        name: "OTEL_EXPORTER_OTLP_ENDPOINT",
                                        value: "http://otel-collector:4317",
                                    },
                                    // ... other necessary OpenTelemetry environment variables
                                ],
                            },
                        ],
                    },
                },
            },
        },
    },
}, { provider: {/*... Your Kubernetes provider if not using the default ...*/}});

export const cronJobName = cronJob.metadata.name;
```

This program will create a CronJob in Kubernetes that runs every 5 minutes. The environment variable `OTEL_EXPORTER_OTLP_ENDPOINT` is presumed to point to an OpenTelemetry collector service that's already set up within your cluster. You'd have to adapt this to your specific environment and OpenTelemetry configuration.

Remember to replace `"myimage"` with the actual container image you want to run as part of your job, and set up any additional env vars required by OpenTelemetry.

As for CronJobber, given that it not a standard resource within Kubernetes, you would need to have the CronJobber CRD applied to your cluster before Pulumi can manage resources of that type.

Ideally, you'd pull in the relevant CRD YAML either from a file or directly as a string, and manage it with `k8s.yaml.ConfigFile` or `k8s.yaml.ConfigGroup` in Pulumi. Once the CRD is applied, and if it's properly set up in your Pulumi program, you can create instances of that CRD (i.e., timezone-aware cron jobs) in a similar manner to the native Kubernetes CronJobs.

Unfortunately, without a specific CRD reference in the registry result, it's not feasible to write a precise Pulumi program for working with CronJobber. If you provide the CRD definition for CronJobber, I can help you incorporate it into the Pulumi program. For OpenTelemetry, ensure your jobs include the necessary instrumentation according to the OpenTelemetry documentation for Kubernetes.